bluuebunny/crossref_metadata_2025 huggingface dataset:
5-Lipoxygenase expression in Langerhans cells of normal human epidermis
Authors: Spanbroek Rainer , Stark Hans-Jürgen , Janßen-Timmen Uwe , Kraft Stefan , Hildner Markus , Andl Thomas , Bosch Franz-Xaver , Fusenig Norbert E. , Bieber Thomas , Rådmark Olof , Samuelsson Bengt , Habenicht Andreas J. R.
Published: July 2002

We studied expression of the 5-lipoxygenase (5-LO) pathway in normal human skin.
In situ
hybridization revealed a 5-LO mRNA-containing epidermal cell (EC) population that was predominantly located in the midportion of the spinous layer, in outer hair root sheaths, and in the epithelial compartment of sebaceous glands. Examination of skin specimens by immunohistochemistry and of primary ECs by flow cytometry mapped the 5-LO protein exclusively to Langerhans cells (LCs). The LC 5-LO protein was largely found in the nuclear matrix, in nuclear envelopes, and perinuclear regions as indicated by
in situ
confocal laser scan microscopy. Reverse transcription–PCR and immunoblot analyses of purified primary EC populations further indicated that LCs are major 5-LO expressing cells. Enriched primary LCs were also found to contain 5-LO activating protein (FLAP), leukotriene (LT) C
4
synthase, and LTA
4
hydrolase. By contrast, 5-LO, FLAP, and LTC
4
synthase were undetectable or largely reduced, but LTA
4
hydrolase transcripts and protein were identified in ECs depleted of LCs. These data show that naïve LCs are major, and possibly the sole, 5-LO pathway expressing cells in the normal human epidermis.
Opposing actions of prostaglandins and oxytocin determine the onset of murine labor
Authors: Gross Gil A. , Imamura Takuji , Luedke Christina , Vogt Sherri K. , Olson Lisa M. , Nelson D. Michael , Sadovsky Yoel , Muglia Louis J.
Published: July 2002

Prostaglandins (PGs) have been recently proven essential for parturition in mice. To dissect the contributions of the two cyclooxygenase (COX) isoforms to the synthesis of PGs during pregnancy, we have characterized the parturition phenotype of COX-1-deficient mice. We find that mice with targeted disruption of the COX-1 gene have delayed parturition resulting in neonatal death. Results of matings of COX-1-deficient females with COX-1 intact males, and blastocyst transfer of COX-1-deficient or -intact embryos into wild-type foster mothers, proved necessity and sufficiency of maternal COX-1 for the normal onset of labor. COX-1 expression is induced in gravid murine uterus and by
in situ
hybridization; this induction is localized to the decidua. Measurement of uterine PGs further confirmed that COX-1 accounted for the majority of PGF2α production. To evaluate the interaction of PGs with oxytocin during murine labor, we generated mice deficient in both oxytocin and COX-1. Surprisingly, the combined oxytocin and COX-1-deficient mice initiated labor at the normal time. COX-1-deficient mice demonstrated impaired luteolysis, as evidenced by elevated serum progesterone concentration and ovarian histology late in gestation, and delayed induction of uterine oxytocin receptors. In contrast, simultaneous oxytocin and COX-1 deficiency restored the normal onset of labor by allowing luteolysis in the absence of elevated PGF2α production. These findings demonstrate that COX-1 is essential for normal labor in the mouse, with a critical function being to overcome the luteotrophic action of oxytocin in late gestation.
A peptide that inhibits hydroxyapatite growth is in an extended conformation on the crystal surface
Authors: Long Joanna R. , Dindot John L. , Zebroski Henry , Kiihne Suzanne , Clark Rutilio H. , Campbell Allison A. , Stayton Patrick S. , Drobny Gary P.
Published: July 2002

Proteins play an important role in the biological mechanisms controlling hard tissue development, but the details of molecular recognition at inorganic crystal interfaces remain poorly characterized. We have applied a recently developed homonuclear dipolar recoupling solid-state NMR technique, dipolar recoupling with a windowless sequence (DRAWS), to directly probe the conformation of an acidic peptide adsorbed to hydroxyapatite (HAP) crystals. The phosphorylated hexapeptide, DpSpSEEK (N6, where pS denotes phosphorylated serine), was derived from the N terminus of the salivary protein statherin. Constant-composition kinetic characterization demonstrated that, like the native statherin, this peptide inhibits the growth of HAP seed crystals when preadsorbed to the crystal surface. The DRAWS technique was used to measure the internuclear distance between two
13
C labels at the carbonyl positions of the adjacent phosphoserine residues. Dipolar dephasing measured at short mixing times yielded a mean separation distance of 3.2 ± 0.1 Å. Data obtained by using longer mixing times suggest a broad distribution of conformations about this average distance. Using a more complex model with discrete α-helical and extended conformations did not yield a better fit to the data and was not consistent with chemical shift analysis. These results suggest that the peptide is predominantly in an extended conformation rather than an α-helical state on the HAP surface. Solid-state NMR approaches can thus be used to determine directly the conformation of biologically relevant peptides on HAP surfaces. A better understanding of peptide and protein conformation on biomineral surfaces may provide design principles useful for the modification of orthopedic and dental implants with coatings and biological growth factors that are designed to enhance biocompatibility with surrounding tissue.
Omega images at the active zone may be endocytotic rather than exocytotic: Implications for the vesicle hypothesis of transmitter release
Authors: Koenig Jane H. , Yamaoka Kageyuki , Ikeda Kazuo
Published: July 2002

A Ca
2+
-dependent synaptic vesicle-recycling pathway emanating from the plasma membrane adjacent to the dense body at the active zone has been demonstrated by blocking pinch-off of recycling membrane by using the
Drosophila
mutant,
shibire
. Exposure of wild-type
Drosophila
synapses to low Ca
2+
/high Mg
2+
saline is shown here to block this active zone recycling pathway at the stage in which invaginations of the plasma membrane develop adjacent to the dense body. These observations, in combination with our previous demonstration that exposure to high Ca
2+
causes “docked” vesicles to accumulate in the identical location where active zone endocytosis occurs, suggest the possibility that a vesicle-recycling pathway emanating from the active zone may exist that is stimulated by exposure to elevated Ca
2+
, thereby causing an increase in vesicle recycling, and is suppressed by exposure to low Ca
2+
saline, thereby blocking newly forming vesicles at the invagination stage. The presence of a Ca
2+
-dependent endocytotic pathway at the active zone opens up the following possibilities: (
i
) electron microscopic omega-shaped images (and their equivalent, freeze fracture dimples) observed at the active zone adjacent to the dense body could represent endocytotic images (newly forming vesicles) rather than exocytotic images; (
ii
) vesicles observed attached to the plasma membrane adjacent to the dense body could represent newly formed vesicles rather than vesicles “docked” for release of transmitter.
The Akt kinase: Molecular determinants of oncogenicity
Authors: Aoki Masahiro , Batista Osvaldo , Bellacosa Alfonso , Tsichlis Philip , Vogt Peter K.
Published: July 2002

The serine-threonine kinase Akt is a downstream target of phosphoinositide 3-kinase (PI 3-kinase); it is activated by the phosphoinositide 3-phosphate-dependent kinases PDK1 and PDK2. Certain mutated forms of Akt induce oncogenic transformation in chicken embryo fibroblast cultures and hemangiosarcomas in young chickens. This ability to transform cells depends on localization of Akt at the plasma membrane and on the kinase activity of Akt. A transdominant negative form of Akt interferes with oncogenic transformation induced by the
p3k
oncogene, which codes for an activated form of PI 3-kinase. Akt is therefore an essential mediator of
p3k
-induced oncogenicity.
Coatomer, but not P200/myosin II, is required for the
in vitro
formation of trans-Golgi network-derived vesicles containing the envelope glycoprotein of vesicular stomatitis virus
Authors: Simon Jean-Pierre , Shen Tian-Huai , Ivanov Ivan E. , Gravotta Diego , Morimoto Takashi , Adesnik Milton , Sabatini David D.
Published: July 2002

Using a cytosol and nucleotide dependent assay that we previously developed, we have investigated the requirement for coat proteins in the
in vitro
production of trans-Golgi network (TGN)-derived vesicles from a Madin-Darby canine kidney (MDCK) cell Golgi fraction that contains the
35
S-labeled, terminally glycosylated, envelope glycoprotein of vesicular stomatitis virus (VSV-G) accumulated in the TGN. We found that the TGN-derived vesicles, like those involved in intra-Golgi transport and in retrograde transport to the endoplasmic reticulum, contain a coatomer coat and that coatomer is required for their formation. Thus, after they are produced with GTPγS, the coated vesicles could be captured on beads containing anticoatomer antibody. Moreover, a cytosolic protein fraction depleted of coatomer could not support vesicle formation but it did so after purified coatomer was added. We also determined that P200/myosin II does not play an essential role in the
in vitro
generation of TGN-derived vesicles. Thus, removal of this protein from the cytosol, by differential salt precipitation or binding to phalloidin-induced actin filaments, had no effect on vesicle generation. Nevertheless, immunodepletion of cytosol using the anti-P200/myosin II AD7 antibody abolished vesicle generation and that antibody was capable of effectively immunocapturing coated vesicles, even when these were generated in the absence of P200/myosin II. These effects, however, are explained by the unexpected finding that the AD7 antibody interacts with undenatured coatomer.
Subcellular metabolic transients and mitochondrial redox waves in heart cells
Authors: Romashko Dmitry N. , Marban Eduardo , O’Rourke Brian
Published: July 2002

Precise matching of energy supply with demand requires delicately balanced control of the enzymes involved in substrate metabolism. In response to a change in substrate supply, the nonlinear properties of metabolic control may induce complex dynamic behavior. Using confocal imaging of flavoprotein redox potential and mitochondrial membrane potential, we show that substrate deprivation leads to subcellular heterogeneity of mitochondrial energization in intact cells. The complex spatiotemporal patterns of redox and matrix potential included local metabolic transients, cell-wide coordinated redox transitions, and propagated metabolic waves both within and between coupled cells. Loss of metabolic synchrony during mild metabolic stress reveals that intra- and intercellular control of mitochondrial function involves diffusible cytoplasmic messengers.
Activity-dependent regulation of Neu differentiation factor/neuregulin expression in rat brain
Authors: Eilam Raya , Pinkas-Kramarski Ronit , Ratzkin Barry J. , Segal Menahem , Yarden Yosef
Published: July 2002

Neu differentiation factor (NDF/neuregulin) is widely expressed in the central and peripheral nervous systems, where it functions as a mediator of the interactions between nerve cells and Schwann, glia, oligodendrocyte, and muscle cells, to control cellular proliferation, differentiation, and migration. NDF binds to two receptor tyrosine kinases, ErbB-3 and ErbB-4. Here we demonstrate that NDF and its ErbB-4 receptor are highly reactive to changes in ambient neuronal activity in the rodent brain in a region-selective manner. Generation of epileptic seizures by using kainic acid, a potent glutamate analog, elevated levels of NDF transcripts in limbic cortical areas, hippocampus, and amygdala. Concomitantly, ErbB-4 mRNA was increased with a similar spatial distribution, but transcription of the other NDF receptor, ErbB-3, did not change. A more moderate stimulation, forced locomotion, was accompanied by an increase in NDF transcripts and protein in the hippocampus and in the motor cortex. Similar changes were found with ErbB-4, but not ErbB-3. Last, a pathway-specific tetanic stimulation of the perforant path, which produced long-term potentiation, was followed by induction of NDF expression in the ipsilateral dentate gyrus and CA3 area of the hippocampus. Taken together, these results indicate that NDF is regulated by physiological activity and may play a role in neural plasticity.
Junction ribonuclease: An activity in Okazaki fragment processing
Authors: Murante Richard S. , Henricksen Leigh A. , Bambara Robert A.
Published: July 2002

The initiator RNAs of mammalian Okazaki fragments are thought to be removed by RNase HI and the 5′-3′ flap endonuclease (FEN1). Earlier evidence indicated that the cleavage site of RNase HI is 5′ of the last ribonucleotide at the RNA-DNA junction on an Okazaki substrate. In current work, highly purified calf RNase HI makes this exact cleavage in Okazaki fragments containing mismatches that distort the hybrid structure of the heteroduplex. Furthermore, even fully unannealed Okazaki fragments were cleaved. Clearly, the enzyme recognizes the transition from RNA to DNA on a single-stranded substrate and not the RNA/DNA heteroduplex structure. We have named this junction RNase activity. This activity exactly comigrates with RNase HI activity during purification strongly suggesting that both activities reside in the same enzyme. After junction cleavage, FEN1 removes the remaining ribonucleotide. Because FEN1 prefers a substrate with a single-stranded 5′-flap structure, the single-stranded activity of junction RNase suggests that Okazaki fragments are displaced to form a 5′-tail prior to cleavage by both nucleases.
The transmembrane domain in viral fusion: Essential role for a conserved glycine residue in vesicular stomatitis virus G protein
Authors: Cleverley Diane Z. , Lenard John
Published: July 2002

The transmembrane (TM) domains of viral fusion proteins are required for fusion, but their precise role is unknown. G protein, the fusion protein of vesicular stomatitis virus, was previously shown to lose syncytia-forming ability if six residues (GLIIGL) were deleted from its TM domain. The 20-residue TM domain of wild-type (TM20) G protein was thus changed into a TM domain of 14 residues (TM14). To assess possible sequence specificity for this loss of function, the two Gly residues in TM20 were replaced with either Ala or Leu. Both mutations resulted in complete loss of fusion activity, as measured by fusion-dependent reporter gene transfer. Single substitutions decreased activity by about half. TM14 was weakly active (15%) but reintroduction of a Gly residue into TM14 by a single Ile → Gly substitution increased activity to 80%. All mutants retained normal hemifusion activity, i.e., lipid mixing between the outer leaflets of the reacting membranes. Thus, at least one TM Gly residue is required for a late step in fusion mediated by G protein. Gly residues were significantly (2.6-fold;
P
= 0.004) more abundant in the TM domains of viral fusion proteins than in those of nonfusion proteins and were distributed differently within the TM domain. Thus, Gly residues in the TM domain of other viral fusion proteins may also prove to be important for fusion activity.
The role of peptides in thymic positive selection of class II major histocompatibility complex-restricted T cells
Authors: Wang Rongfang , Nelson Andrew , Kimachi Kazuhiko , Grey Howard M. , Farr Andrew G.
Published: July 2002

A thymic epithelial cell line transfected with I-Ekwas used in reaggregate cultures to study the role of peptides in positive selection of T cell receptor transgenic thymocytes. In this system, positive selection of CD4 SP cells occurred only after the addition of exogenous peptide. Analysis of antigen analogs indicated an inverse relationship between the antigenicity for peripheral T cells and the concentration of peptide required for positive selection. These data are most consistent with an avidity (rather than an affinity) model of positive selection, in which ligand density and the affinity of T cell receptor act in concert to determine the fate of developing thymocytes.
Release of caspase-9 from mitochondria during neuronal apoptosis and cerebral ischemia
Authors: Krajewski Stanislaw , Krajewska Maryla , Ellerby Lisa M. , Welsh Kate , Xie Zhihua , Deveraux Quinn L. , Salvesen Guy S. , Bredesen Dale E. , Rosenthal Robert E. , Fiskum Gary , Reed John C.
Published: July 2002

Caspase-9 is critical for cytochrome
c
(cyto-c)-dependent apoptosis and normal brain development. We determined that this apical protease in the cyto-c pathway for apoptosis resides inside mitochondria in several types of cells, including cardiomyocytes and many neurons. Caspase-9 is released from isolated mitochondria on treatment with Ca
2+
or Bax, stimuli implicated in ischemic neuronal cell death that are known to induce cyto-c release from mitochondria. In neuronal cell culture models, apoptosis-inducing agents trigger translocation of caspase-9 from mitochondria to the nucleus, which is inhibitable by Bcl-2. Similarly, in an animal model of transient global cerebral ischemia, caspase-9 release from mitochondria and accumulation in nuclei was observed in hippocampal and other vulnerable neurons exhibiting early postischemic changes preceding apoptosis. Loss of mitochondrial barrier function during neuronal damage from ischemia or other insults therefore may play an important role in making certain caspases available to participate in apoptosis.
Causalgia, pathological pain, and adrenergic receptors
Authors: Perl Edward R.
Published: July 2002

Control of expression of molecular receptors for chemical
messengers and modulation of these receptors’ activity are now
established as ways to alter cellular reaction. This paper extends
these mechanisms to the arena of pathological pain by presenting the
hypothesis that increased expression of α-adrenergic receptors in
primary afferent neurons is part of the etiology of pain in classical
causalgia. It is argued that partial denervation by lesion of
peripheral nerve or by tissue destruction induces a change in
peripheral nociceptors, making them excitable by sympathetic activity
and adrenergic substances. This excitation is mediated by
α-adrenergic receptors and has a time course reminiscent of
experimental denervation supersensitivity. The change in neuronal
phenotype is demonstrable after lesions of mixed nerves or of the
sympathetic postganglionic supply. Similar partial denervations also
produce a substantial increase in the number of dorsal root ganglion
neurons evidencing the presence of α-adrenergic receptors. The
hypothesis proposes the increased presence of α-adrenergic receptors
in primary afferent neurons to result from an altered gene expression
triggered by cytokines/growth factors produced by disconnection of
peripheral nerve fibers from their cell bodies. These additional
adrenergic receptors are suggested to make nociceptors and other
primary afferent neurons excitable by local or circulating
norepinephrine and epinephrine. For central pathways, the adrenergic
excitation would be equivalent to that produced by noxious events and
would consequently evoke pain. In support, evidence is cited for a form
of denervation supersensitivity in causalgia and for increased
expression of human α-adrenergic receptors after loss of sympathetic
activity.
Long-term survival and function of intrahepatic islet allografts in rhesus monkeys treated with humanized anti-CD154
Authors: Kenyon Norma S. , Chatzipetrou Maria , Masetti Michele , Ranuncoli Alessandra , Oliveira Maria , Wagner Joseph L. , Kirk Allan D. , Harlan David M. , Burkly Linda C. , Ricordi Camillo
Published: July 2002

Reported effects of anti-CD154 treatment on autoimmunity, alloreactivity, and inflammatory events mediated by macrophages and endothelial cells indicated that it might be an ideal agent for the prevention of intrahepatic islet allograft failure. This hypothesis was tested in MHC-mismatched rhesus monkeys. Transplantation of an adequate number of viable islets resulted in engraftment and insulin independence in six of six recipients treated with anti-CD154 (hu5c8) induction plus monthly maintenance therapy (post-operative day >125, >246, >266, >405, >419, >476). Anti-CD154 (hu5c8) displayed no inhibitory effect on islet cell function. For monkeys followed for >100 days, continued improvement in graft function, as determined by first phase insulin release in response to intravenous glucose, was observed after the first 100 days post-transplant. No evidence of toxicity or infectious complications has been observed. All recipients treated with anti-CD154 became specifically nonresponsive to donor cells in mixed lymphocyte reactions. Furthermore, three monkeys are now off therapy (>113, >67, and >54 days off anti-CD154), with continued insulin independence and donor-specific mixed lymphocyte reaction hyporeactivity. In striking contrast to all previously tested strategies, transplantation of an adequate number of functional islets under the cover of anti-CD154 (hu5c8) monotherapy consistently allows for allogeneic islet engraftment and long-term insulin independence in this highly relevant preclinical model.
A phenotype for enigmatic DNA polymerase II: A pivotal role for pol II in replication restart in UV-irradiated
Escherichia
coli
Authors: Rangarajan Savithri , Woodgate Roger , Goodman Myron F.
Published: July 2002

DNA synthesis in
Escherichia coli
is inhibited transiently after UV irradiation. Induced replisome reactivation or “replication restart” occurs shortly thereafter, allowing cells to complete replication of damaged genomes. At the present time, the molecular mechanism underlying replication restart is not understood. DNA polymerase II (pol II), encoded by the
dinA
(
polB
) gene, is induced as part of the global SOS response to DNA damage. Here we show that pol II plays a pivotal role in resuming DNA replication in cells exposed to UV irradiation. There is a 50-min delay in replication restart in mutant cells lacking pol II. Although replication restart appears normal in Δ
umuDC
strains containing pol II, the restart process is delayed for >90 min in cells lacking both pol II and UmuD′
2
C. Because of the presence of pol II, a transient replication-restart burst is observed in a “quick-stop” temperature-sensitive pol III mutant (
dnaE486
) at nonpermissive temperature. However, complete recovery of DNA synthesis requires the concerted action of both pol II and pol III. Our data demonstrate that pol II and UmuD′
2
C act in independent pathways of replication restart, thereby providing a phenotype for pol II in the repair of UV-damaged DNA.
The small GTP-binding protein Rac is a regulator of cell death in plants
Authors: Kawasaki Tsutomu , Henmi Kenji , Ono Eiichiro , Hatakeyama Satoru , Iwano Megumi , Satoh Hikaru , Shimamoto Ko
Published: July 2002

Cell death plays important roles in the development and defense of plants as in other multicellular organisms. Rapid production of reactive oxygen species often is associated with plant defense against pathogens, but their molecular mechanisms are not known. We introduced the constitutively active and the dominant negative forms of the small GTP-binding protein
OsRac1
, a rice homolog of human Rac, into the wild type and a lesion mimic mutant of rice and analyzed H
2
O
2
production and cell death in transformed cell cultures and plants. The results indicate that Rac is a regulator of reactive oxygen species production as well as cell death in rice.
Salt-induced detour through compact regions of the protein folding landscape
Authors: Otzen Daniel E. , Oliveberg Mikael
Published: July 2002

In several cases, inorganic salts have been used to induce partly structured states in protein folding. But what is the nature of these states: Do they represent key stepping stones in the folding process, or are they circumstantial pitfalls in the energy landscape? Here we report that, in the case of the two-state protein S6, the salt-induced collapsed state is off the usual folding routes in the sense that it is prematurely collapsed and slows down folding by several orders of magnitude. Although this species is over-compact, it is not a dead-end trap but may fold by alternative channels to the native state.
β2-Chimaerin is a novel target for diacylglycerol: Binding properties and changes in subcellular localization mediated by ligand binding to its C1 domain
Authors: Caloca Maria José , Garcia-Bermejo Maria Laura , Blumberg Peter M. , Lewin Nancy E. , Kremmer Elisabeth , Mischak Harald , Wang Shaomeng , Nacro Kassoum , Bienfait Bruno , Marquez Victor E. , Kazanietz Marcelo G.
Published: July 2002

The members of the chimaerin family of Rac-GTPase-activating proteins possess a single C1 domain with high homology to those present in protein kinase C (PKC) isozymes. This domain in PKCs is involved in phorbol ester and diacylglycerol (DAG) binding. We previously have demonstrated that one of the chimaerin isoforms, β2-chimaerin, binds phorbol esters with high affinity. In this study we analyzed the properties of β2-chimaerin as a DAG receptor by using a series of conformationally constrained cyclic DAG analogues (DAG lactones) as probes. We identified analogs that bind to β2-chimaerin with more than 100-fold higher affinity than 1-oleoyl-2-acetylglycerol. The potencies of these analogs approach those of the potent phorbol ester tumor promoters. The different DAG lactones show some selectivity for this novel receptor compared with PKCα. Cellular studies revealed that these DAG analogs induce translocation of β2-chimaerin from cytosolic (soluble) to particulate fractions. Using green fluorescent protein-fusion proteins for β2-chimaerin we determined that this novel receptor translocates to the perinuclear region after treatment with DAG lactones. Binding and translocation were prevented by mutation of the conserved Cys-246 in the C1 domain. The structural homology between the C1 domain of β2-chimaerin and the C1b domain of PKCδ also was confirmed by modeling analysis. Our results demonstrate that β2-chimaerin is a high affinity receptor for DAG through binding to its C1 domain and supports the emerging concept that multiple pathways transduce signaling through DAG and the phorbol esters.
Tonic inhibition alternates in paired neurons that set direction of fish escape reaction
Authors: Hatta Kohei , Korn Henri
Published: July 2002

Crossed antagonism between activities in neurons subserving alternating movements such as swimming or walking has been described in a number of systems. The role of reciprocal inhibition has been implicated in these activities, but involvement of rhythmic ongoing fluctuations of membrane potential, called synaptic “noise,” has not been examined. In the Mauthner (M) cells, which control the direction of escape, this activity is inhibitory. We report that in the zebrafish (
Danio rerio
), inhibitory synaptic noise exhibits prolonged bursts of rhythmic, inhibitory postsynaptic potentials, which attenuate the M cell’s sensibility to excitatory sensory drives. Furthermore, paired intracellular recordings have shown that inhibitory synaptic noise alternates between two distinct states, noisy and quiet, which are out of phase in the two cells. Firing of either M cell resets this pattern by reducing the inhibition in the contralateral one. This suggests that an avoidance reflex in one direction may favor initiation, by the opposite M cell, of a subsequent escape toward a more appropriate location.
In vivo
inhibition of rat stellate cell activation by soluble transforming growth factor β type II receptor: A potential new therapy for hepatic fibrosis
Authors: George Jacob , Roulot Dominique , Koteliansky Victor E. , Bissell D. Montgomery
Published: July 2002

Transforming growth factor β (TGF-β) is a well characterized cytokine that appears to play a major role in directing the cellular response to injury, driving fibrogenesis, and, thus, potentially underlying the progression of chronic injury to fibrosis. In this study, we report the use of a novel TGF-β receptor antagonist to block fibrogenesis induced by ligation of the common bile duct in rats. The antagonist consisted of a chimeric IgG containing the extracellular portion of the TGF-β type II receptor. This “soluble receptor” was infused at the time of injury; in some experiments it was given at 4 days after injury, as a test of its ability to reverse fibrogenesis. The latter was assessed by expression of collagen, both as the mRNA in stellate cells isolated from control or injured liver and also by quantitative histochemistry of tissue sections. When the soluble receptor was administered at the time of injury, collagen I mRNA in stellate cells from the injured liver was 26% of that from animals receiving control IgG (
P
< 0.0002); when soluble receptor was given after injury induction, collagen I expression was 35% of that in control stellate cells (
P
< 0.0001). By quantitative histochemistry, hepatic fibrosis in treated animals was 55% of that in controls. We conclude that soluble TGF-β receptor is an effective inhibitor of experimental fibrogenesis
in vivo
and merits clinical evaluation as a novel agent for controlling hepatic fibrosis in chronic liver injury.
Invariance between subjects of brain wave representations of language
Authors: Suppes Patrick , Han Bing , Epelboim Julie , Lu Zhong-Lin
Published: July 2002

In three experiments, electric brain waves of 19 subjects were recorded under several different experimental conditions for two purposes. One was to test how well we could recognize which sentence, from a set of 24 or 48 sentences, was being processed in the cortex. The other was to study the invariance of brain waves between subjects. As in our earlier work, the analysis consisted of averaging over trials to create prototypes and test samples, to both of which Fourier transforms were applied, followed by filtering and an inverse transformation to the time domain. A least-squares criterion of fit between prototypes and test samples was used for classification. In all three experiments, averaging over subjects improved the recognition rates. The most significant finding was the following. When brain waves were averaged separately for two nonoverlapping groups of subjects, one for prototypes and the other for test samples, we were able to recognize correctly 90% of the brain waves generated by 48 different sentences about European geography.
Studies on the interactions between human replication factor C and human proliferating cell nuclear antigen
Authors: Zhang Gang , Gibbs Emma , Kelman Zvi , O’Donnell Michael , Hurwitz Jerard
Published: July 2002

Proliferating cell nuclear antigen (PCNA) is a processivity factor required for DNA polymerase δ (or ɛ)-catalyzed DNA synthesis. When loaded onto primed DNA templates by replication factor C (RFC), PCNA acts to tether the polymerase to DNA, resulting in processive DNA chain elongation. In this report, we describe the identification of two separate peptide regions of human PCNA spanning amino acids 36–55 and 196–215 that bind RFC by using the surface plasmon resonance technique. Site-directed mutagenesis of residues within these regions in human PCNA identified two specific sites that affected the biological activity of PCNA. Replacement of the aspartate 41 residue by an alanine, serine, or asparagine significantly impaired the ability of PCNA to (
i
) support the RFC/PCNA-dependent polymerase δ-catalyzed elongation of a singly primed DNA template; (
ii
) stimulate RFC-catalyzed DNA-dependent hydrolysis of ATP; (
iii
) be loaded onto DNA by RFC; and (
iv
) activate RFC-independent polymerase δ-catalyzed synthesis of poly dT. Introduction of an alanine at position 210 in place of an arginine also reduced the efficiency of PCNA in supporting RFC-dependent polymerase δ-catalyzed elongation of a singly primed DNA template. However, this mutation did not significantly alter the ability of PCNA to stimulate DNA polymerase δ in the absence of RFC but substantially lowered the efficiency of RFC-catalyzed reactions. These results are in keeping with a model in which surface exposed regions of PCNA interact with RFC and the subsequent loading of PCNA onto DNA orients the elongation complex in a manner essential for processive DNA synthesis.
N-
Methyl-
d
-aspartate antagonists and apoptotic cell death triggered by head trauma in developing rat brain
Authors: Pohl D. , Bittigau P. , Ishimaru M. J. , Stadthaus D. , Hübner C. , Olney J. W. , Turski L. , Ikonomidou C.
Published: July 2002

Morbidity and mortality from head trauma is highest among children. No animal model mimicking traumatic brain injury in children has yet been established, and the mechanisms of neuronal degeneration after traumatic injury to the developing brain are not understood. In infant rats subjected to percussion head trauma, two types of brain damage could be characterized. The first type or primary damage evolved within 4 hr and occurred by an excitotoxic mechanism. The second type or secondary damage evolved within 6–24 hr and occurred by an apoptotic mechanism. Primary damage remained localized to the parietal cortex at the site of impact. Secondary damage affected distant sites such as the cingulate/retrosplenial cortex, subiculum, frontal cortex, thalamus and striatum. Secondary apoptotic damage was more severe than primary excitotoxic damage. Morphometric analysis demonstrated that the
N
-methyl-
d
-aspartate receptor antagonists 3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonate and dizocilpine protected against primary excitotoxic damage but increased severity of secondary apoptotic damage. 2-Sulfo-α-phenyl-
N-tert
-butyl-nitrone, a free radical scavenger, did not affect primary excitotoxic damage but mitigated apoptotic damage. These observations demonstrate that apoptosis and not excitotoxicity determine neuropathologic outcome after traumatic injury to the developing brain. Whereas free radical scavengers may prove useful in therapy of head trauma in children,
N
-methyl-
d
-aspartate antagonists should be avoided because of their propensity to increase severity of apoptotic damage.
Crystal structure of the HLA-Cw3 allotype-specific killer cell inhibitory receptor KIR2DL2
Authors: Snyder Greg A. , Brooks Andrew G. , Sun Peter D.
Published: July 2002

Killer cell inhibitory receptors (KIR) protect class I HLAs expressing target cells from natural killer (NK) cell-mediated lysis. To understand the molecular basis of this receptor-ligand recognition, we have crystallized the extracellular ligand-binding domains of KIR2DL2, a member of the Ig superfamily receptors that recognize HLA-Cw1, 3, 7, and 8 allotypes. The structure was determined in two different crystal forms, an orthorhombic P212121and a trigonal P3221 space group, to resolutions of 3.0 and 2.9 Å, respectively. The overall fold of this structure, like KIR2DL1, exhibits K-type Ig topology withcis-proline residues in both domains that define β-strand switching, which sets KIR apart from the C2-type hematopoietic growth hormone receptor fold. The hinge angle of KIR2DL2 is approximately 80°, 14° larger than that observed in KIR2DL1 despite the existence of conserved hydrophobic residues near the hinge region. There is also a 5° difference in the observed hinge angles in two crystal forms of 2DL2, suggesting that the interdomain hinge angle is not fixed. The putative ligand-binding site is formed by residues from several variable loops with charge distribution apparently complementary to that of HLA-C. The packing of the receptors in the orthorhombic crystal form offers an intriguing model for receptor aggregation on the cell surface.
Natural and experimental oral infection of nonhuman primates by bovine spongiform encephalopathy agents
Authors: Bons Nöelle , Mestre-Frances Nadine , Belli Patrick , Cathala Françoise , Gajdusek D. Carleton , Brown Paul
Published: July 2002

Experimental lemurs either were infected orally with the agent of bovine spongiform encephalopathy (BSE) or were maintained as uninfected control animals. Immunohistochemical examination for proteinase-resistant protein (prion protein or PrP) was performed on tissues from two infected but still asymptomatic lemurs, killed 5 months after infection, and from three uninfected control lemurs. Control tissues showed no staining, whereas PrP was detected in the infected animals in tonsil, gastrointestinal tract and associated lymphatic tissues, and spleen. In addition, PrP was detected in ventral and dorsal roots of the cervical spinal cord, and within the spinal cord PrP could be traced in nerve tracts as far as the cerebral cortex. Similar patterns of PrP immunoreactivity were seen in two symptomatic and 18 apparently healthy lemurs in three different French primate centers, all of which had been fed diets supplemented with a beef protein product manufactured by a British company that has since ceased to include beef in its veterinary nutritional products. This study of BSE-infected lemurs early in their incubation period extends previous pathogenesis studies of the distribution of infectivity and PrP in natural and experimental scrapie. The similarity of neuropathology and PrP immunostaining patterns in experimentally infected animals to those observed in both symptomatic and asymptomatic animals in primate centers suggests that BSE contamination of zoo animals may have been more widespread than is generally appreciated.
Identification of type II restriction and modification systems in
Helicobacter pylori
reveals their substantial diversity among strains
Authors: Xu Qing , Morgan Richard D. , Roberts Richard J. , Blaser Martin J.
Published: July 2002

A total of 22 type II restriction endonucleases with 18 distinct specificities have been identified in six
Helicobacter pylori
strains. Among these 18 specificities are three completely new endonucleases,
Hpy
178III,
Hpy
99I, and
Hpy
188I, that specifically cleave DNA at TCNNGA, CGWCG, and TCNGA sites, respectively. The set of endonucleases identified in each strain varies, but all have four- or five-base recognition sequences. Among 16
H. pylori
strains, examination of the DNA modification status at the recognition sites of 15 restriction endonucleases reveals that each strain has a substantially different complement of type II modification systems. We conclude that the type II restriction-modification systems in
H. pylori
are highly diverse between strains, a unique characteristic of
H. pylori
. The diverse methylation status of
H. pylori
chromosomal DNA may serve as a new typing system to discriminate
H. pylori
isolates for epidemiological and clinical purposes. This study also demonstrates that
H. pylori
is a rich source of type II restriction endonucleases.
The catalytic subunit of DNA-dependent protein kinase selectively regulates p53-dependent apoptosis but not cell-cycle arrest
Authors: Wang Sa , Guo Min , Ouyang Honghai , Li Xiaoling , Cordon-Cardo Carlos , Kurimasa Akihiro , Chen David J. , Fuks Zvi , Ling C. Clifton , Li Gloria C.
Published: July 2002

DNA damage induced by ionizing radiation (IR) activates p53, leading to the regulation of downstream pathways that control cell-cycle progression and apoptosis. However, the mechanisms for the IR-induced p53 activation and the differential activation of pathways downstream of p53 are unclear. Here we provide evidence that the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) serves as an upstream effector for p53 activation in response to IR, linking DNA damage to apoptosis.
DNA-PKcs
knockout (
DNA-PKcs
−/−) mice were exposed to whole-body IR, and the cell-cycle and apoptotic responses were examined in their thymuses. Our data show that IR induction of apoptosis and Bax expression, both mediated via p53, was significantly suppressed in the thymocytes of
DNA-PKcs
−/− mice. In contrast, IR-induced cell-cycle arrest and p21 expression were normal. Thus, DNA-PKcs deficiency selectively disrupts p53-dependent apoptosis but not cell-cycle arrest. We also confirmed previous findings that p21 induction was attenuated and cell-cycle arrest was defective in the thymoctyes of whole body-irradiated
Atm
−/− mice, but the apoptotic response was unperturbed. Taken together, our results support a model in which the upstream effectors DNA-PKcs and Atm selectively activate p53 to differentially regulate cell-cycle and apoptotic responses. Whereas Atm selects for cell-cycle arrest but not apoptosis, DNA-PKcs selects for apoptosis but not cell-cycle arrest.
Sociology and the public understanding of science: from rationalization to rhetoric1
Authors: Locke Simon
Published: July 2002

This paper contributes to the reappraisal of sociological theories of modernity inspired by the sociology of scientific knowledge (SSK). As much as these theories rely on received ideas about the nature of science that SSK has called into doubt, so do they rely on ideas about the public understanding of science. Public understanding of science has been assumed to conform to the monolithic logic and perception of science associated with rationalization, leading to an impoverished view of the cognitive outlook of the modern individual. Rationalization has become the basis for the construction of theoretical critique of science divorced from any clear reference to public understanding, with the result that theory has encountered considerable problems in accounting for public scepticism towards science. However, rather than question rationalization, the more typical strategy has been to propose radical changes in the modernization process, such as postmodernism and the risk society. Against this, an alternative view of public understanding is advanced drawn from SSK and rhetorical psychology. The existence of the sociological critique of science, and SSK in particular, suggests that the meaning of science in modernity is not monolithic but multiple, arising out of a central dilemma over the universal form of knowledge‐claims and their necessarily particular, human and social grounding. This dilemma plays out not only in intellectual discourses about science, but also in the public's understanding of science. This argument is used to call for further sociological research into public understanding and to encourage sociologists to recognize the central importance of the topic to a proper understanding of modernity.
Evolutionary Theory and Self‐perception: Sex Differences in Body Esteem Predictors of Self‐perceived Physical and Sexual Attractiveness and Self‐Esteem
Authors: Wade T. Joel
Published: July 2002

Responses to the body esteem scale (Franzoi & Shields, 1984) and multiple regression were used to determine if evolutionary biological theory is relevant to an understanding of self‐perceived physical and sexual attractiveness and self‐esteem and to determine if physical and sexual attractiveness are the same construct. It was hypothesized that regression models of physical and sexual attractiveness would differ within and across sex groups and that models of self‐esteem would differ across sex groups in accordance with evolutionary theory. These hypotheses were supported. Attributes of the body related to fecundity and successful mothering characteristics predicted for women and attributes of the body related to strength and dominance predicted for men. In addition, attributes of the body dealing with sexual maturity were stronger predictors of sexual attractiveness. Physical and sexual attractiveness are not the same constructs. This research indicates that evolutionary bological theory can provide relevant insight for an understanding of self‐perceived attractiveness and self‐esteem.
Eastern Finno-Ugrian Cooperation and Foreign Relations
Authors: Taagepera Rein
Published: July 2002

Britons and Iranians do not wax poetic when they discover that “one, two, three” sound vaguely similar in English and Persian. Finns and Hungarians at times do. When I speak of “Finno-Ugrian cooperation,” I am referring to a linguistic label that joins peoples whose languages are so distantly related that in most world contexts it would evoke no feelings of kinship. Similarities in folk culture may largely boil down to worldwide commonalities in peasant cultures at comparable technological stages. The racial features of Estonians and Mari may be quite disparate. Limited mutual intelligibility occurs only within the Finnic group in the narrow sense (Finns, Karelians, Vepsians, Estonians), the Permic group (Udmurts and Komi), and the Mordvin group (Moksha and Erzia). Yet, despite this almost abstract foundation, the existence of a feeling of kinship is very real. Myths may have no basis in fact, but belief in myths does occur. Before denigrating the beliefs of indigenous and recently modernized peoples as nineteenth-century relics, the observer might ask whether the maintenance of these beliefs might serve some functional twenty-first-century purpose.
The Politics of Ethnic Cleansing: The P.P.R., The P.Z.Z. and Wielkopolska's Nationalist Revolution, 1944–1946
Authors: Curp T. David
Published: July 2002

“… all of society is caught up in a hatred of Germany … [this] creates a serious possibility of uniting all of society into one entire national front.”

Władysław Gomułka

Three costly revolutions began in Poland between spring 1944 and summer 1946. The first two were primarily state-sponsored political and socioeconomic revolutions initiated by a minority comprising the Moscow-appointed and -controlled Polish Workers' Party (Polska Partia Robotnicza, P.P.R.) and their allies. Although they dominated the commanding heights of regional and national politics and administration, the P.P.R. and its supporters faced fierce opposition and waged these revolutions with only partial success, relying heavily on fraud and force. These ongoing state-sponsored transformations established an uneven hold on Polish society and depended upon the police power of the new Polish state and, ultimately, the Soviet Union. When the Soviet Union was no longer willing to support its satellites in Eastern Europe by force of arms and the Polish people dismantled their regime's coercive power, much of the laboriously developed political and socioeconomic superstructure of the People's Republic of Poland collapsed.
Congruence on child rearing in families with early adolescent and middle adolescent children
Authors: Lanz Margherita , Scabini Eugenia , Vermulst Ad A. , Gerris Jan R.M.
Published: July 2002

This study investigates the extent to which parents’ and adolescent’s reports of parental child-rearing behaviour are in agreement with each other. The aim of this study is twofold. The first aim is to verify whether familial congruence (congruence between family members) about child rearing exists. The second aim is to verify whether the level of congruence varies with the stage of the adolescent (early and middle) and gender of parent or child. The sample consists of 788 families with a child between the ages of 9 and 16 years. Congruence scores were computed on diverse aspects of child rearing: material rewarding, expression of affection, conformity, autonomy, ignoring, and punishment. The results show that familial congruence exists, not only between father and mother but also between parents and their children. A second result is that congruence between parents and their children increases from early to middle adolescence indicating that children become more competent interpreting their parents’ behaviour.