bluuebunny/crossref_metadata_2025 huggingface dataset:
Review Article: Cystic Degeneration/Spongiosis Hepatis in Rats
Authors: Karbe Eberhard , Kerlin Roy L.
Published: July 2002

Cystic degeneration/spongiosis hepatis in rats has been proposed to be a preneoplastic and/or neoplastic lesion by some authors, because of its proliferative properties and persistent increased cell turnover rate in stop experiments using hepatocarcinogens , and the assumption that it can develop into a sarcoma. The neoplastic potential of cystic degeneration is questioned in this review article. Cystic degeneration, which appears to derive from altered Ito cells, does not have neoplastic histomorphologi c characteristics, although it may be composed of cells with an increased mitotic index. In this regard, persistent proliferation is also seen with other nonneoplastic lesions. Arguments are presented to show that the induced, probably extremely rare sarcoma that was associated with cystic degeneration most likely derives from the very rare induced spherical Ito-cell aggregate with an unusually high cellular turnover rate in rats treated with hepatocarcinogens , and not from cystic degeneration. Also, in none of 12 referenced standard oncogenicity studies with chemically induced cystic degeneration was the lesion associated with mesenchymal (Ito-cell) tumors. Consequently, evidence is lacking that cystic degeneration in rats should be classifi ed as a preneoplastic or neoplastic lesion.

The 12 oncogenicity studies in rats with induced cystic degeneration showed a marked sex predilection, with males more likely to develop either spontaneous or chemically induced lesions. In these 12 studies, cystic degeneration was more often associated with hepatocellular hypertrophy or hepatotoxicity, rather than hepatocarcinogenicity. Thus, it is concluded that hepatocarcinogens induce cystic degeneration, not because they are carcinogenic, but because they have other effects on the liver, and that cystic degeneration may be a secondary/reparative change. Cystic degeneration in fi sh parallels the situation in rats in many respects, yet the existence of the lesion in other species, including man, is not as well supported. Based on the data presented in this review, spontaneous and induced cystic degeneration in rats and fi sh is not a preneoplastic or neoplastic lesion and risk assessment for man can be based on no-effect levels and safety margins, as for other nonneoplasti c adverse effects that have no counterpart in man.
The pharmacological profile of ovalbumin‐induced paw oedema in rats
Authors: Feitosa R. F. G. , Melcíades G. B. , Assreuy A. M. S. , Rocha M. F. G. , Ribeiro R. A. , Lima A. A. M.
Published: July 2002

Rats are commonly used in anaphylaxis models, mainly in intestinal anaphylaxis. Hypersensitivity mechanisms are complex and they are not clearly defined. Ovalbumin (OVA) is commonly used for studies on the hypersensitivity mechanism. However, the potential pro‐inflammatory mediators induced by this antigen in the model of paw oedema in immunized rats are still not completely understood. This work examines the pharmacological modulation of several mediators involved in rat hind paw immune oedema induced by OVA. Wistar rats were previously immunized (14‐18 days) with OVA (30 μg, intraperitoneally) or sham‐sensitized with aluminum hydroxide (control). The paw volumes were measured before the antigenic stimuli and 1, 2, 3 and 4 h after the intraplantar injection of OVA (10 μg/paw). Subcutaneous injection of dexamethasone, diphenhydramine, cyproheptadine, chlorpromazine or methysergide significantly inhibited (p < 0.05) the allergic paw oedema. The dual inhibitor of cyclooxygenase and lipoxygenase (NDGA), the cyclooxygenase inhibitor (indomethacin), the lipoxygenase inhibitor (MK‐886), the PAF antagonist (WEB 2086), the mast cell stabilizer (ketotifen), and the anti‐histamine (meclizine) did not inhibit the immune oedema. In addition, thalidomide and pentoxifylline (anti‐tumour necrosis factor drugs) were ineffective against OVA‐induced oedema. The fact that indomethacin, MK‐886, NDGA and WEB 2086 are unable to inhibit this allergic oedema indicates that the dexamethasone action seems not to be via phospholipase A2, but possibly due to the synthesis and/or the inhibitory activity of cytokines. The paw oedema inhibition by diphenhydramine, but not by meclizine, may suggest a different mechanism, which is independent of the effect of histamine. These data indicate that allergic oedema is more sensitive to anti‐serotonin drugs, mainly anti‐5‐HT2, suggesting that the principal mediator of this inflammatory response is serotonin.
The effect of trinitrobenzene sulfonic acid on gut‐derived smooth muscle cell arachidonic acid metabolism: role of endogenous prostanoids
Authors: Longo W. E. , Smith G. S. , Deshpande Y. , Reickenberg C. , Kaminski D. L.
Published: July 2002

The contribution of smooth muscle cells as a potential source of eicosanoid production during inflammatory states remains to be elucidated. We investigated the effect of trinitrobenzene sulfonic acid (TNB), a known pro‐inflammatory agent, on jejunal smooth muscle cell eicosanoid production. Human gut‐derived smooth muscle cells (HISM) were incubated with TNB for 1 hour. Additionally, some cells were preincubated with either dimethylthiourea, or indomethacin for 1 hour before exposure to identical concentrations of TNB. Incubation with TNB led to significant increases in PGE2 and
6‐keto PGF‐1α release, but not leukotriene B4 release; responses which were both inhibited by dimethylthiourea and indomethacin treatment. Our results suggest that gutderived smooth muscle cells may represent an important source of proinflammatory prostanoids but not leukotrienes during inflammatory states of the intestine. The inhibition of prostanoid activity by thiourea may be mediated by suppression of cyclooxygenase activity in this cell line.
Arachidonic Acid and Freshly Isolated Human Bone Marrow Mononuclear Cells
Authors: Denizot Y. , Desplat V. , Dulery C. , Trimoreau F. , Praloran V.
Published: July 2002

Arachidonic acid (AA), a fatty acid found in the human bone marrow plasma, is the precursor of eicosanoids that modulate bone marrow haematopoiesis. To further our understanding of the role of AA in the bone marrow physiology, we have assessed its incorporation in human bone marrow mononuclear cells. Gas chromatography analysis indicates the presence of AA in their fatty acid composition. In bone marrow mononuclear cells, [3H]‐AA is incorporated into triglycerides and is later delivered into phospholipids, a result not observed with blood mononuclear cells. Prelabelling‐chase experiments indicate a trafficking of labelled AA from phosphatidylcholine to phosphatidylethanolamine. Stimulation of prelabelled bone marrow mononuclear cells with granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) results in the release of a part of the incorporated labelled AA. Finally, exogenous AA (up to 1 μM) has no significant effect on cell growth. In conclusion, human bone marrow mononuclear cells participate to the control of marrow AA concentrations by incorporating AA into phospholipids and triglycerides. In turn, bone marrow mononuclear cells can release AA in response to the potent haematopoietic growth factor GM‐CSF.
A Randomized Comparison of two Short Intensive Chemotherapy Regimens in Children and Young Adults With Osteosarcoma: Results in Patients With Metastases: A Study of the European Osteosarcoma Intergroup
Authors: Bramwell Vivien H. C. , Burgers Marion V. , Souhami Robert L. , Taminiau Antonie H. M. , Van Der Eijken Jan W. , Craft Alan W. , Malcolm Archie J. , Uscinska Barbara , Kirkpatrick Anna L. , Machin David , Van Glabbeke Martine M.
Published: July 2002

Purpose. To report the outcome of 37 patients with metastatic osteosarcoma entered into a large randomized trial (EOI
80831/MRC B002) comparing two different regimens of chemotherapy in patients with osteosarcoma.

Methods. Patients with biopsy‐proven osteosarcoma localized and metastatic, age 40 years or younger, were randomized
to receive either two‐drug treatment with doxorubicin/cisplatin (DOX 25 mg m−2
day−1 × 3 + DDP 100 mg m−2 on
day 1 q 3 weeks × 6 courses) or three‐drug treatment comprising high‐dose methotrexate (HDMTX 8 mg m−2
administered every weeks × 4 courses) given 10 days before DOX/DDP.

Results. Twenty‐four patients with metastatic disease received the two‐drug arm treatment and 13 received three‐drug
treatment. Despite chance imbalance in numbers, there were no major differences in age, sex, primary site or performance
status. Baseline alkaline phosphatase (AP) was elevated more frequently (96 vs 42%) in the two‐drug arm. Twenty‐one
of 24 patients in the two‐drug arm and 11/13 patients in the three‐drug arm had evaluable primary tumors concurrent with
metastases. Respective clinical response rates for the two‐ and three‐drug arms were 48% and 40% for primary tumors,
and 33% and 55% for metastases. Respective survivals at 2 and 4 years were 36% and 9% for the two‐drug arm, and 69%
and 52% for the three‐drug arm, and survival was better for patients with normal AP at presentation. When adjusted for
AP, survival was not significantly different between the two treatments (hazard ratio 0.52, 95% confidence interval
0.22–1.23, p = 0.14). There were three long‐term survivors among the metastatic patients, all of whom received the
three‐drug therapy.

Discussion. It is likely that random bias in the population (small numbers, imbalance in size of groups, uneven distribution
of AP) accounts for the difference in outcome favoring the three‐drug treatment in patients with metastatic disease. More
reliance can be placed on the finding that disease‐free and overall survival in the adjuvant component of this study
(Bramwell et al., J Clin Oncol 1992; 10: 1579–91) were better after two‐drug treatment.
Enhanced MDM2 Oncoprotein Expression in Soft Tissue Sarcoma: Several Possible Regulatory Mechanisms
Authors: Pollock Raphael E. , Lang Aiquing , El-Naggar Adel K. , Radinsky Robert , Hung Mien Chie
Published: July 2002

Purpose. MDM2 is an oncogene whose protein product may promote tumorigenesis by blocking
wild‐type p53 tumor suppressor mediated G0/G1 cell cycle arrest, thereby inhibiting repair of damaged DNA prior to cell division. While
MDM2 DNA amplification is frequently observed in human sarcoma, the mechanisms linking this amplification to MDM2
oncoprotein over‐production as well as its functional significance have not been well characterized in patients with soft
tissue sarcoma.

Methods. A tissue bank of resected soft tissue sarcomas and autologous normal tissues was assembled; all specimens were
snap frozen within 15 min of resection. DNA and RNA were extracted from tissues using isoamyl alcohol and phenol
chloroform extraction methods, respectively; cell lysates were prepared using PBSTDS lysis buffer. DNA and mRNA were
confirmed as being non‐degraded and were then examined for MDM2 DNA amplification (Southern blots) and mRNA
over‐expression (Northern blots) using actin (DNA) and glyceraldehyde‐3‐phosphate dehydrogenase (mRNA) as loading
controls. The MDM2 protein was examined on Western blots using the MDM2‐specific monoclonal antibody IF2
(Oncogene Science, Inc). The presence of p53 DNA and expression of p53 mRNA was examined by rehybridizing the
Southern and Northern filters using a p53‐specific cDNA probe.

Results. Soft tissue sarcomas and autologous normal tissues were screened for MDM2 DNA amplification, which was
detected in 10 of 30 tumors screened. After screening, there was sufficient biomaterials from six specimens for subsequent
Northern and Western analysis to see whether MDM2 gene amplification correlated with over‐expression of MDM2
mRNA and MDM2 protein. In addition, we examined whether other mechanisms may lead to over‐expression of the
MDM2 oncoprotein. Several possible mechanisms of MDM2 oncoprotein over‐expression were identified. These most
commonly included MDM2 DNA amplification, MDM2 mRNA over‐expression and MDM2 oncoprotein over‐expression.
However, some soft tissue sarcoma patient specimens had no evidence of MDM2 mRNA over‐expression yet had
MDM2 oncoprotein over‐production in the tumor relative to autologous normal tissue, implying possible post‐transcriptional
regulation. Of functional relevance, MDM2 oncoprotein over‐production by tumors was associated with large
decreases in the percentage of cells in the G0/G1 cell cycle interface compared with autologous normal tissue cells.

Discussion. It is likely that there are multiple mechanisms underlying human soft tissue sarcoma MDM2 oncoprotein
over‐production. Consequently, strategies that decrease MDM2 over‐production, such as transcriptional repression to
inhibit MDM2 promoter activity or RNA antisense approaches, may ultimately offer the best therapeutic efficacy.
Role of LIM Domains in Mediating Signaling Protein Interactions
Authors: Brown Susan , Coghill Imogen D. , McGrath Meagan J. , Robinson Paul A.
Published: July 2002

LIM domains are double zinc‐finger motifs that mediate protein interactions between transcription factors, cytoskeletal and signaling proteins. This review outlines the protein interactions mediated by LIM domains with signaling proteins including tyrosine and serine/threonine kinases and phosphatases.
Bcl-2 Lies Downstream of Parathyroid Hormone–related Peptide in a Signaling Pathway That Regulates Chondrocyte Maturation during Skeletal Development
Authors: Amling Michael , Neff Lynn , Tanaka Sakae , Inoue Daisuke , Kuida Keisuke , Weir Eleanor , Philbrick William M. , Broadus Arthur E. , Baron Roland
Published: July 2002

Parathyroid hormone–related peptide (PTHrP) appears to play a major role in skeletal development. Targeted disruption of the PTHrP gene in mice causes skeletal dysplasia with accelerated chondrocyte maturation (Amizuka, N., H. Warshawsky, J.E. Henderson, D. Goltzman, and A.C. Karaplis. 1994. J. Cell Biol. 126:1611–1623; Karaplis, A.C., A. Luz, J. Glowacki, R.T. Bronson, V.L.J. Tybulewicz, H.M. Kronenberg, and R.C. Mulligan. 1994. Genes Dev. 8: 277–289). A constitutively active mutant PTH/PTHrP receptor has been found in Jansen-type human metaphyseal chondrodysplasia, a disease characterized by delayed skeletal maturation (Schipani, E., K. Kruse, and H. Jüppner. 1995. Science (Wash. DC). 268:98– 100). The molecular mechanisms by which PTHrP affects this developmental program remain, however, poorly understood. We report here that PTHrP increases the expression of Bcl-2, a protein that controls programmed cell death in several cell types, in growth plate chondrocytes both in vitro and in vivo, leading to delays in their maturation towards hypertrophy and apoptotic cell death. Consequently, overexpression of PTHrP under the control of the collagen II promoter in transgenic mice resulted in marked delays in skeletal development. As anticipated from these results, deletion of the gene encoding Bcl-2 leads to accelerated maturation of chondrocytes and shortening of long bones. Thus, Bcl-2 lies downstream of PTHrP in a pathway that controls chondrocyte maturation and skeletal development.
Spindle Dynamics during Meiosis in Drosophila Oocytes
Authors: Endow Sharyn A. , Komma Donald J.
Published: July 2002

Mature oocytes of Drosophila are arrested in metaphase of meiosis I. Upon activation by ovulation or fertilization, oocytes undergo a series of rapid changes that have not been directly visualized previously. We report here the use of the Nonclaret disjunctional (Ncd) microtubule motor protein fused to the green fluorescent protein (GFP) to monitor changes in the meiotic spindle of live oocytes after activation in vitro. Meiotic spindles of metaphase-arrested oocytes are relatively stable, however, meiotic spindles of in vitro–activated oocytes are highly dynamic: the spindles elongate, rotate around their long axis, and undergo an acute pivoting movement to reorient perpendicular to the oocyte surface. Many oocytes spontaneously complete the meiotic divisions, permitting visualization of progression from meiosis I to II. The movements of the spindle after oocyte activation provide new information about the dynamic changes in the spindle that occur upon re-entry into meiosis and completion of the meiotic divisions. Spindles in live oocytes mutant for a lossof-function ncd allele fused to gfp were also imaged. The genesis of spindle defects in the live mutant oocytes provides new insights into the mechanism of Ncd function in the spindle during the meiotic divisions.
Integrin α2β1 Is a Receptor for the Cartilage Matrix Protein Chondroadherin
Authors: Camper Lisbet , Heinegård Dick , Lundgren-Åkerlund Evy
Published: July 2002

Chondroadherin (the 36-kD protein) is a leucine-rich, cartilage matrix protein known to mediate adhesion of isolated chondrocytes. In the present study we investigated cell surface proteins involved in the interaction of cells with chondroadherin in cell adhesion and by affinity purification. Adhesion of bovine articular chondrocytes to chondroadherin-coated dishes was dependent on Mg2+ or Mn2+ but not Ca2+. Adhesion was partially inhibited by an antibody recognizing β1 integrin subunit. Chondroadherin-binding proteins from chondrocyte lysates were affinity purified on chondroadherin-Sepharose. The β1 integrin antibody immunoprecipitated two proteins with molecular mass ∼110 and 140 kD (nonreduced) from the EDTA-eluted material. These results indicate that a β1 integrin on chondrocytes interacts with chondroadherin. To identify the α integrin subunit(s) involved in interaction of cells with the protein, we affinity purified chondroadherin-binding membrane proteins from human fibroblasts. Immunoprecipitation of the EDTA-eluted material from the affinity column identified α2β1 as a chondroadherin-binding integrin. These results are in agreement with cell adhesion experiments where antibodies against the integrin subunit α2 partially inhibited adhesion of human fibroblast and human chondrocytes to chondroadherin. Since α2β1 also is a receptor for collagen type II, we tested the ability of different antibodies against the α2 subunit to inhibit adhesion of T47D cells to collagen type II and chondroadherin. The results suggested that adhesion to collagen type II and chondroadherin involves similar or nearby sites on the α2β1 integrin. Although α2β1 is a receptor for both collagen type II and chondroadherin, only adhesion of cells to collagen type II was found to mediate spreading.
ERM (Ezrin/Radixin/Moesin)-based Molecular Mechanism of Microvillar Breakdown at an Early Stage of Apoptosis
Authors: Kondo Takahisa , Takeuchi Kosei , Doi Yoshinori , Yonemura Shigenobu , Nagata Shigekazu , Tsukita Shoichiro , Tsukita Sachiko
Published: July 2002

Breakdown of microvilli is a common early event in various types of apoptosis, but its molecular mechanism and implications remain unclear. ERM (ezrin/radixin/moesin) proteins are ubiquitously expressed microvillar proteins that are activated in the cytoplasm, translocate to the plasma membrane, and function as general actin filament/plasma membrane cross-linkers to form microvilli. Immunofluorescence microscopic and biochemical analyses revealed that, at the early phase of Fas ligand (FasL)–induced apoptosis in L cells expressing Fas (LHF), ERM proteins translocate from the plasma membranes of microvilli to the cytoplasm concomitant with dephosphorylation. When the FasL-induced dephosphorylation of ERM proteins was suppressed by calyculin A, a serine/threonine protein phosphatase inhibitor, the cytoplasmic translocation of ERM proteins was blocked. The interleukin-1β–converting enzyme (ICE) protease inhibitors suppressed the dephosphorylation as well as the cytoplasmic translocation of ERM proteins. These findings indicate that during FasL-induced apoptosis, the ICE protease cascade was first activated, and then ERM proteins were dephosphorylated followed by their cytoplasmic translocation, i.e., microvillar breakdown. Next, to examine the subsequent events in microvillar breakdown, we prepared DiO-labeled single-layered plasma membranes with the cytoplasmic surface freely exposed from FasL-treated or nontreated LHF cells. On single-layered plasma membranes from nontreated cells, ERM proteins and actin filaments were densely detected, whereas those from FasL-treated cells were free from ERM proteins or actin filaments. We thus concluded that the cytoplasmic translocation of ERM proteins is responsible for the microvillar breakdown at an early phase of apoptosis and that the depletion of ERM proteins from plasma membranes results in the gross dissociation of actin-based cytoskeleton from plasma membranes. The physiological relevance of this ERM protein–based microvillar breakdown in apoptosis will be discussed.
Golgi Vesiculation and Lysosome Dispersion in Cells Lacking Cytoplasmic Dynein
Authors: Harada A. , Takei Y. , Kanai Y. , Tanaka Y. , Nonaka S. , Hirokawa N.
Published: July 2002

Cytoplasmic dynein, a minus end–directed, microtubule-based motor protein, is thought to drive the movement of membranous organelles and chromosomes. It is a massive complex that consists of multiple polypeptides. Among these polypeptides, the cytoplasmic dynein heavy chain (cDHC) constitutes the major part of this complex. To elucidate the function of cytoplasmic dynein, we have produced mice lacking cDHC by gene targeting. cDHC−/− embryos were indistinguishable from cDHC+/−or cDHC+/+ littermates at the blastocyst stage. However, no cDHC−/− embryos were found at 8.5 d postcoitum. When cDHC−/− blastocysts were cultured in vitro, they showed interesting phenotypes. First, the Golgi complex became highly vesiculated and distributed throughout the cytoplasm. Second, endosomes and lysosomes were not concentrated near the nucleus but were distributed evenly throughout the cytoplasm. Interestingly, the Golgi “fragments” and lysosomes were still found to be attached to microtubules.

These results show that cDHC is essential for the formation and positioning of the Golgi complex. Moreover, cDHC is required for cell proliferation and proper distribution of endosomes and lysosomes. However, molecules other than cDHC might mediate attachment of the Golgi complex and endosomes/lysosomes to microtubules.
Structure and Assembly of the Nup84p Complex
Authors: Siniossoglou Symeon , Lutzmann Malik , Santos-Rosa Helena , Leonard Kevin , Mueller Shirley , Aebi Ueli , Hurt Ed
Published: July 2002

The Nup84p complex consists of five nucleoporins (Nup84p, Nup85p, Nup120p, Nup145p-C, and Seh1p) and Sec13p, a bona fide subunit of the COPII coat complex. We show that a pool of green fluorescent protein–tagged Sec13p localizes to the nuclear pores in vivo, and identify sec13 mutant alleles that are synthetically lethal with nup85Δ and affect the localization of a green fluorescent protein–Nup49p reporter protein. In the electron microscope, sec13 mutants exhibit structural defects in nuclear pore complex (NPC) and nuclear envelope organization. For the assembly of the complex, Nup85p, Nup120p, and Nup145p-C are essential. A highly purified Nup84p complex was isolated from yeast under native conditions and its molecular mass was determined to be 375 kD by quantitative scanning transmission electron microscopy and analytical ultracentrifugation, consistent with a monomeric complex. Furthermore, the Nup84p complex exhibits a Y-shaped, triskelion-like morphology 25 nm in diameter in the transmission electron microscope. Thus, the Nup84p complex constitutes a paradigm of an NPC structural module with distinct composition, structure, and a role in nuclear mRNA export and NPC bio- genesis.
The Reversible Modification Regulates the Membrane-Binding State of Apg8/Aut7 Essential for Autophagy and the Cytoplasm to Vacuole Targeting Pathway
Authors: Kirisako Takayoshi , Ichimura Yoshinobu , Okada Hisashi , Kabeya Yukiko , Mizushima Noboru , Yoshimori Tamotsu , Ohsumi Mariko , Takao Toshifumi , Noda Takeshi , Ohsumi Yoshinori
Published: July 2002

Autophagy and the Cvt pathway are examples of nonclassical vesicular transport from the cytoplasm to the vacuole via double-membrane vesicles. Apg8/Aut7, which plays an important role in the formation of such vesicles, tends to bind to membranes in spite of its hydrophilic nature. We show here that the nature of the association of Apg8 with membranes changes depending on a series of modifications of the protein itself. First, the carboxy-terminal Arg residue of newly synthesized Apg8 is removed by Apg4/Aut2, a novel cysteine protease, and a Gly residue becomes the carboxy-terminal residue of the protein that is now designated Apg8FG. Subsequently, Apg8FG forms a conjugate with an unidentified molecule “X” and thereby binds tightly to membranes. This modification requires the carboxy-terminal Gly residue of Apg8FG and Apg7, a ubiquitin E1-like enzyme. Finally, the adduct Apg8FG-X is reversed to soluble or loosely membrane-bound Apg8FG by cleavage by Apg4. The mode of action of Apg4, which cleaves both newly synthesized Apg8 and modified Apg8FG, resembles that of deubiquitinating enzymes. A reaction similar to ubiquitination is probably involved in the second modification. The reversible modification of Apg8 appears to be coupled to the membrane dynamics of autophagy and the Cvt pathway.
Membrane-Type 1 Matrix Metalloproteinase Cleaves Cd44 and Promotes Cell Migration
Authors: Kajita Masahiro , Itoh Yoshifumi , Chiba Tadashige , Mori Hidetoshi , Okada Akiko , Kinoh Hiroaki , Seiki Motoharu
Published: July 2002

Migratory cells including invasive tumor cells frequently express CD44, a major receptor for hyaluronan and membrane-type 1 matrix metalloproteinase (MT1-MMP) that degrades extracellular matrix at the pericellular region. In this study, we demonstrate that MT1-MMP acts as a processing enzyme for CD44H, releasing it into the medium as a soluble 70-kD fragment. Furthermore, this processing event stimulates cell motility; however, expression of either CD44H or MT1-MMP alone did not stimulate cell motility. Coexpression of MT1-MMP and mutant CD44H lacking the MT1-MMP–processing site did not result in shedding and did not promote cell migration, suggesting that the processing of CD44H by MT1-MMP is critical in the migratory stimulation. Moreover, expression of the mutant CD44H inhibited the cell migration promoted by CD44H and MT1-MMP in a dominant-negative manner. The pancreatic tumor cell line, MIA PaCa-2, was found to shed the 70-kD CD44H fragment in a MT1-MMP–dependent manner. Expression of the mutant CD44H in the cells as well as MMP inhibitor treatment effectively inhibited the migration, suggesting that MIA PaCa-2 cells indeed use the CD44H and MT1-MMP as migratory devices. These findings revealed a novel interaction of the two molecules that have each been implicated in tumor cell migration and invasion.
Lipopolysaccharide Induces Disseminated Endothelial Apoptosis Requiring Ceramide Generation
Authors: Haimovitz-Friedman Adriana , Cordon-Cardo Carlos , Bayoumy Shariff , Garzotto Mark , McLoughlin Maureen , Gallily Ruth , Edwards Carl K. , Schuchman Edward H. , Fuks Zvi , Kolesnick Richard
Published: July 2002

The endotoxic shock syndrome is characterized by systemic inflammation, multiple organ damage, circulatory collapse and death. Systemic release of tumor necrosis factor (TNF)-α and other cytokines purportedly mediates this process. However, the primary tissue target remains unidentified. The present studies provide evidence that endotoxic shock results from disseminated endothelial apoptosis. Injection of lipopolysaccharide (LPS), and its putative effector TNF-α, into C57BL/6 mice induced apoptosis in endothelium of intestine, lung, fat and thymus after 6 h, preceding nonendothelial tissue damage. LPS or TNF-α injection was followed within 1 h by tissue generation of the pro-apoptotic lipid ceramide. TNF-binding protein, which protects against LPS-induced death, blocked LPS-induced ceramide generation and endothelial apoptosis, suggesting systemic TNF is required for both responses. Acid sphingomyelinase knockout mice displayed a normal increase in serum TNF-α in response to LPS, yet were protected against endothelial apoptosis and animal death, defining a role for ceramide in mediating the endotoxic response. Furthermore, intravenous injection of basic fibroblast growth factor, which acts as an intravascular survival factor for endothelial cells, blocked LPS-induced ceramide elevation, endothelial apoptosis and animal death, but did not affect LPS-induced elevation of serum TNF-α. These investigations demonstrate that LPS induces a disseminated form of endothelial apoptosis, mediated sequentially by TNF and ceramide generation, and suggest that this cascade is mandatory for evolution of the endotoxic syndrome.
Protection against Invasive Amebiasis by a Single Monoclonal Antibody Directed against a Lipophosphoglycan Antigen Localized on the Surface of Entamoeba histolytica
Authors: Marinets Alexandra , Zhang Tonghai , Guillén Nancy , Gounon Pierre , Bohle Barbara , Vollmann Ute , Scheiner Otto , Wiedermann Gerhard , Stanley Samuel L. , Duchêne Michael
Published: July 2002

A panel of monoclonal antibodies was raised from mice immunized with a membrane preparation from Entamoeba histolytica, the pathogenic species causing invasive amebiasis in humans. Antibody EH5 gave a polydisperse band in immunoblots from membrane preparations from different E. histolytica strains, and a much weaker signal from two strains of the nonpathogenic species Entamoeba dispar. Although the exact chemical structure of the EH5 antigen is not yet known, the ability of the antigen to be metabolically radiolabeled with [32P]phosphate or [3H]glucose, its sensitivity to digestion by mild acid and phosphatidylinositol-specific phospholipase C, and its specific extraction from E. histolytica trophozoites by a method used to prepare lipophosphoglycans from Leishmania showed that it could be classified as an amebal lipophosphoglycan. Confocal immunofluorescence and immunogold labeling of trophozoites localized the antigen on the outer face of the plasma membrane and on the inner face of internal vesicle membranes. Antibody EH5 strongly agglutinated amebas in a similar way to concanavalin A (Con A), and Con A bound to immunoaffinity-purified EH5 antigen. Therefore, surface lipophosphoglycans may play an important role in the preferential agglutination of pathogenic amebas by Con A. The protective ability of antibody EH5 was tested in a passive immunization experiment in a severe combined immunodeficient (SCID) mouse model. Intrahepatic challenge of animals after administration of an isotype-matched control antibody or without treatment led to the development of a liver abscess in all cases, whereas 11 out of 12 animals immunized with the EH5 antibody developed no liver abscess. Our results demonstrate the importance and, for the first time, the protective capacity of glycan antigens on the surface of the amebas.
Facilitation of β Selection and Modification of Positive Selection in the Thymus of Pd-1–Deficient Mice
Authors: Nishimura Hiroyuki , Honjo Tasuku , Minato Nagahiro
Published: July 2002

PD-1 is an immunoglobulin superfamily member bearing an immunoreceptor tyrosine-based inhibitory motif, and disruption of the PD-1 gene results in the development of lupus-like autoimmune diseases. In this study, we examined effects of the PD-1 deficiency on the thymocyte differentiation at the clonal level using T cell receptor (TCR)-β (Vβ8) and TCR-α/β (H-Y and 2C) transgenic mice. In these TCR transgenic lines, PD-1 expression in the thymus was variably augmented, but as in the normal mice, confined largely to the CD4−CD8− thymocytes. The transgenic mice crossed with PD-1−/− mice in the neutral genetic backgrounds exhibited selective increase in the CD4+CD8+ (DP) population with little effect on other thymocytes subsets. Similarly, the absence of PD-1 facilitated expansion of DP thymocytes in recombination activating gene (RAG)-2−/− mice by anti-CD3ε antibody injection. On the other hand, H-Y or 2C transgenic PD-1−/− mice with the positively selecting background showed significantly reduced efficiency for the generation of CD8+ single positive cells bearing the transgenic TCR-α/β in spite of the increased DP population. These results collectively indicate that PD-1 negatively regulates the β selection and modulates the positive selection, and suggest that PD-1 deficiency may lead to the significant alteration of mature T cell repertoire.
Depletion of Cd4+ T Cells Causes Reactivation of Murine Persistent Tuberculosis despite Continued Expression of Interferon γ and Nitric Oxide Synthase 2
Authors: Scanga Charles A. , Mohan V.P. , Yu Keming , Joseph Heather , Tanaka Kathryn , Chan John , Flynn JoAnne L.
Published: July 2002

Tuberculosis is a major cause of death in much of the world. Current estimates are that one-third of the world's population is infected with Mycobacterium tuberculosis. Most infected persons control the infection but in many cases may not eliminate the organism. Reactivation of this clinically latent infection is responsible for a large proportion of active tuberculosis cases. A major risk factor for reactivation of latent tuberculosis is HIV infection, suggesting a role for the CD4+ T cell subset in maintaining the latent persistent infection. In this study, we tested the requirement for CD4+ T cells in preventing reactivation in a murine model of latent tuberculosis. Antibody-mediated depletion of CD4+ T cells resulted in rapid reactivation of a persistent infection, with dramatically increased bacterial numbers in the organs, increased pathology in the lungs, and decreased survival. Although CD4+ T cells are believed to be a major source of interferon (IFN)-γ, expression of the gene for IFN-γ in the lungs of CD4+ T cell–depleted mice was similar to that in control mice. In addition, inducible nitric oxide synthase production and activity was unimpaired after CD4+ T cell depletion, indicating that macrophage activation was present even during CD4+ T cell deficiency. These data indicate that CD4+ T cells are necessary to prevent reactivation but may have roles in addition to IFN-γ production and macrophage activation in controlling a persistent tuberculous infection.
Fist/Hipk3
Authors: Rochat-Steiner Véronique , Becker Karin , Micheau Olivier , Schneider Pascal , Burns Kim , Tschopp Jürg
Published: July 2002

Fas is a cell surface death receptor that signals apoptosis. Several proteins have been identified that bind to the cytoplasmic death domain of Fas. Fas-associated death domain (FADD), which couples Fas to procaspase-8, and Daxx, which couples Fas to the Jun NH2-terminal kinase pathway, bind independently to the Fas death domain. We have identified a 130-kD kinase designated Fas-interacting serine/threonine kinase/homeodomain-interacting protein kinase (FIST/HIPK3) as a novel Fas-interacting protein. Binding to Fas is mediated by a conserved sequence in the COOH terminus of the protein. FIST/HIPK3 is widely expressed in mammalian tissues and is localized both in the nucleus and in the cytoplasm. In transfected cell lines, FIST/HIPK3 causes FADD phosphorylation, thereby promoting FIST/HIPK3–FADD–Fas interaction. Although Fas ligand–induced activation of Jun NH2-terminal kinase is impaired by overexpressed active FIST/HIPK3, cell death is not affected. These results suggest that Fas-associated FIST/HIPK3 modulates one of the two major signaling pathways of Fas.
Kinetics of Acute Hepatitis B Virus Infection in Humans
Authors: Whalley Simon A. , Murray John M. , Brown Dave , Webster George J.M. , Emery Vincent C. , Dusheiko Geoffrey M. , Perelson Alan S.
Published: July 2002

Using patient data from a unique single source outbreak of hepatitis B virus (HBV) infection, we have characterized the kinetics of acute HBV infection by monitoring viral turnover in the serum during the late incubation and clinical phases of the disease in humans. HBV replicates rapidly with minimally estimated doubling times ranging between 2.2 and 5.8 d (mean 3.7 ± 1.5 d). After a peak viral load in serum of nearly 1010 HBV DNA copies/ml is attained, clearance of HBV DNA follows a two or three phase decay pattern with an initial rapid decline characterized by mean half-life (t1/2) of 3.7 ± 1.2 d, similar to the t1/2 observed in the noncytolytic clearance of covalently closed circular DNA for other hepadnaviruses. The final phase of virion clearance occurs at a variable rate (t1/2 of 4.8 to 284 d) and may relate to the rate of loss of infected hepatocytes. Free virus has a mean t1/2 of at most 1.2 ± 0.6 d. We estimate a peak HBV production rate of at least 1013 virions/day and a maximum production rate of an infected hepatocyte of 200–1,000 virions/day, on average. At this peak rate of virion production we estimate that every possible single and most double mutations would be created each day.
RECENT OBSERVATIONS OF SOME OF THE NOVÆ
Authors: Barnard E. E.
Published: July 2002

Observations of Nova Cygni 1920, Nova Aquilae 1918, Nova Ophiuchi 1919 and Nova Persei 1901 are reported.
Deuterium, Lithium, and the Hubble Deep Field
Authors: Casuso E. , Beckman J. E.
Published: July 2002

This article presents a theoretical framework for the evolution of the light-element nuclides in the Galactic disk. By understanding this evolution correctly, we can reliably obtain the primordial abundances of the nuclides D, 4He, and 7Li. We use two key assumptions, those of (1) infall of metal-poor gas to the disk at an increasing rate and (2) destruction, as well as production (except for D), of fragile nuclides in hot, relatively dense supergiant envelopes. Light nuclides are accelerated by supernova shocks, and many are confined to hot interstellar zones by magnetic fields. Their repeated passage through the hot envelopes causes depletion, which peaked during the main star-forming phase of Galaxy evolution around z ≈ 1, as measured from the Hubble Deep Field. This mechanism has dominated stellar depletion in reducing the D/H abundance from its primordial value of ≃2 × 10-4 to its solar system value of ≃2.5 × 10-5 and subsequently to the current interstellar medium value of 1.5 × 10-5. The model accounts well for the solar system and the current ratios of 7Li/6Li and 11B/10B. It fits extremely well a standard big bang nucleosynthesis model with baryon density ≃0.05.
Spectropolarimetric Clues to the Structure and Evolutionary Status of MWC 349A
Authors: Bellovary Jillian M. , Nordsieck Kenneth H. , Hoffman Jennifer L.
Published: July 2002

We present visible wavelength spectropolarimetric measurements of the emission-line star MWC 349A and its close optical companion MWC 349B, conducted with the HPOL spectropolarimeter on both the 0.9 m telescope at the University of Wisconsin's Pine Bluff Observatory and the 3.5 m WIYN telescope on Kitt Peak. Our measurements allow us to estimate the interstellar polarization contribution and thus constrain the intrinsic polarization of MWC 349A, which we find to be consistent in position angle with the dusty disk seen perpendicular to the bipolar outflow. Our analysis reopens the possibility that MWC 349A may be part of the Cyg OB2 association, suggests that it is not a physical companion to MWC 349B, and supports the classification of MWC 349A as a pre–main-sequence B[e] star.
Direct and charge-exchange inelastic processes in ion-atom collisions. III. He+-Ar
Authors: V Sidis  , J C Brenot  , J Pommier  , M Barat  , O Bernardini  , D C Lorents  , F T Smith
Published: July 2002

For pt.II see ibid., vol.9, p.269 (1976). The He+-Ar collision is studied experimentally in the 100-2000 eV laboratory energy range. Differential cross sections sigma ( theta ) are determined for the main inelastic processes. Direct excitations of Ar are identified by the electrostatic energy analysis of the scattered ions and charge-exchange processes are investigated by a time-of-flight technique. The He+-Ar system differs markedly from the He+-He and He+-Ne collisions previously studied by the importance of the charge-exchange processes into excited states of Ar+and by the weakness of the charge exchange in the ground state. Ab initio potential energy curves and differential cross section calculations confirm the proposed excitation mechanism, at least for moderate-energy collisions.
Scattering matrix for curve-crossing collisions
Authors: A Barany
Published: July 2002

The Stueckelberg approximate two-state curve-crossing partial-wave scattering matrix is discussed and found to be a good approximation provided the parameters are correctly computed and the coupling region is well separated from the classical turning points. A novel parametrisation of the close-curve-crossing reduced scattering matrix for the BNO or DT model has been found. There are only two non-trivial parameters, but analytical results and preliminary numerical calculations show these to be slowly varying smooth functions of L.
Atomic transition probabilities from the relativistic pseudopotential approach
Authors: P Hafner  , W H E Schwarz
Published: July 2002

The 'relativistic pseudopotential approach' is applied to the calculation of electric-dipole transition probabilities in the valence shell of heavy atoms. An adequate transition operator is derived. The lowest spin-allowed and spin-forbidden transitions of the heavier group I and II elements and a series of higher transitions of Ca I and II, Cs, I, Ba I and II, Au I and Hg I are calculated. The influence of the core-valence correlation is investigated with Hameed's core-polarisation correction.
Auger electron emission from target ions under heavy-ion impact after molecular dissociation
Authors: R Mann  , F Folkmann  , R S Peterson  , Gy Szabo  , K -O Groeneveld
Published: July 2002

The line shape of the (1s2s2p)4P (metastable) to (1s2)1S+e-Auger electron transition from heavy-ion impact is measured for targets containing carbon, nitrogen, oxygen and neon. The angular distribution of this transition is also measured for molecular gas targets containing carbon. Ar, Kr, Xe and U projectiles from the UNILAC were used with energy 1.4 MeV amu-1. It is found that the line shape depends strongly on the initial molecular target. Kinematic effects such as projectile-induced target recoil do not account well for these changes. A simple model is proposed that assumes the creation of a highly ionised molecule. The line shape is due to Doppler broadening from the velocity acquired by the dissociation of the molecule. Reasonable agreement between this Coulomb explosion model and the experimental results is found, allowing dissociation velocities to be calculated from the experimental line shapes.
Model-potential method for the calculation of atom-rare-gas interactions: application to the Na-Ne system
Authors: M Philippe  , F Masnou-Seeuws  , P Valiron
Published: July 2002

Results of model-potential calculations for the ground-state and the first nine excited-state molecular curves of the Na-Ne system are presented. A two-parameter model potential for the electron-neon interaction can be fitted to scattering data. The molecular curves are not affected by the uncertainty of the data. The introduction of a non-local orthogonality condition to the neon core orbitals is discussed. For internuclear distances R>or=5 au, the authors' results agree within 5% with the laser spectroscopy determination of the well in the X2Sigma and A2Pi potential curves, and with the far wing profile determined by York et al., (1975). A blue satellite is predicted at 1224 cm-1. The accuracy at smaller internuclear distances is limited by the lack of precision in the NaNe+core-core repulsion. In contrast with pseudopotential calculations, a 450 cm-1well is obtained in the delta 3d curve at 4.5 au. The sigma 4s, sigma 3d and sigma 4p states present a barrier at 10 au and a well at 4.5 au.
Multiple scattering effect on electron mobilities in dense gases
Authors: T F O'Malley
Published: July 2002

A simple model is found for the anomalous density dependence of electron mobilities by applying the energy shift and broadening of multiple scattering theory plus the uncertainty principle to the transport equations. The shift alone when properly applied immediately predicts the observed positive and negative effects in Ar. The exponential decrease observed in H2, CO2, and He is found to result from a combination of their negative energy shift plus the broadening, which together push the electron distribution function down to localised negative energy states. Possible application of the model to amorphous semiconductors is also discussed.
Application of ab-initio optical potentials to low-energy electron-H2scattering
Authors: B I Schneider  , L A Collins
Published: July 2002

The linear algebraic technique is extended from the static-exchange level to treat correlation and polarisation effects in electron-molecule collisions by means of an optical potential. The technique is applied to e-H2scattering.
Triple and double differential cross sections for electron impact ionisation of helium for 'energy-sharing' kinematics
Authors: J T N Kimman  , Pan Guang-Yan  , C W McCurdy  , F J de Heer
Published: July 2002

The triple differential cross sections for electron impact ionisation of helium are investigated for 'energy-sharing' kinematics. A comparison is made with results of the simplified eikonal impulse approximation (EIA). Over the electron impact energy range from 200-2000 eV the authors also present absolute double differential cross sections for electron impact ionisation, in which only one existing electron is detected. It is shown that these cross sections are closely related to triple differential cross sections, in which two electrons are detected, for some scattering geometries. A model, which includes Rutherford scattering by the nucleus, is suggested, in order to explain the large discrepancy between the integrated EIA and the experimental data for very asymmetric energy disposition between the outgoing electrons.
L X-ray anisotropy and L3-subshell alignment of heavy atoms induced by ion impact
Authors: W Jitschin  , R Hippler  , R Shanker  , H Kleinpoppen  , R Schuch  , H O Lutz
Published: July 2002

The anisotropy emission of the Ll X-ray line from heavy atoms (54<or=Z2<or=92) has been investigated experimentally for ion impact (1<or=Z1<or=79) in the energy range 0.15 to 10 MeV amu-1. In the case of single ionisation, the collisionally induced alignment of the L3subshell can be derived. The data for H and He projectiles are reasonably well described by direct Coulomb ionisation theories. With increasing Z1, the measured anisotropy becomes considerably smaller than for H impact. No pronounced dependence on the projectile nuclear charge is found although for different projectiles different ionisation mechanisms (direct ionisation, promotion of molecular orbitals) dominate.
An analysis of the exchange correlation effects in the isoelectronic series of the2S ground state of lithium in terms of the interelectronic distance
Authors: J M Ugalde
Published: July 2002

The hole formalism has been used to elucidate exchange correlation effects in the2S state of the lithium isoelectronic series. This approach provides a very simple physical picture of the effects of electron correlation from the point of view of the reference electron. In particular the calculations demonstrate that the probability of finding any two electrons with the same spin is reduced at both small and large interelectronic distances with a concomitant increase of the probability of their being at intermediate distances. Also a general tendency for the radius of the Fermi hole to increase as a function of r1has been shown together with the existence of a non-zero limit. Finally the authors have found that the polarisation of the Fermi hole is spherically symmetric with respect to the nucleus and has very little dependence on the distance of the reference electron from the nucleus.
New forbidden lines in the L emission spectrum of64Gd
Authors: G B Deodhar  , P P Varma
Published: July 2002

A systematic study of the L emission spectrum of gadolinium reveals the existence of the quadrupole lines λλ 1502·01 and 1616·22 X.U. corresponding to the transitions LINIV,Vand LIINIII, respectively, and the octupole line LIIMV(λ 1834·77 X.U.). The presence of the dipole line LIIOI(γ8) and that of the quadrupole line corresponding to the transition LIOIV,V, reported for this element by Sakellaridis, have been confirmed. Also the discrepancy between the wavelength values reported for the dipole line LIIIOI(β7) by Coster and Sakellaridis has been removed.