bluuebunny/crossref_metadata_2025 huggingface dataset:
RETRACTED: New findings of the correlation between acupoints and corresponding brain cortices using functional MRI
Authors: Cho Z. H. , Chung S. C. , Jones J. P. , Park J. B. , Park H. J. , Lee H. J. , Wong E. K. , Min B. I.
Published: July 2002

A preliminary study of the correlation between acupuncture points (acupoints) for the treatment of eye disorders suggested by ancient Oriental literature and the corresponding brain localization for vision described by Western medicine was performed by using functional MRI (fMRI). The vision-related acupoint (VA1) is located in the lateral aspect of the foot, and when acupuncture stimulation is performed there, activation of occipital lobes is seen by fMRI. Stimulation of the eye by directly using light results in similar activation in the occipital lobes by fMRI. The experiment was conducted by using conventional checkerboard 8-Hz light-flash stimulation of the eye and observation of the time-course data. This was followed by stimulation of the VA1 by using the same time-course paradigm as visual light stimulation. Results obtained with 12 volunteers yielded very clean data and very close correlations between visual and acupuncture stimulation. We have also stimulated nonacupoints 2 to 5 cm away from the vision-related acupoints on the foot as a control, and activation in the occipital lobes was not observed. The results obtained demonstrate the correlation between activation of specific areas of brain cortices and corresponding acupoint stimulation predicted by ancient acupuncture literature.
Identification of the sites of interaction between the scaffold and outer shell in herpes simplex virus-1 capsids by difference electron imaging
Authors: Zhou Z. Hong , Macnab Sharon J. , Jakana Joanita , Scott L. Ridgway , Chiu Wah , Rixon Frazer J.
Published: July 2002

Formation of herpes simplex virus-1 capsids requires the presence of intact scaffolding proteins. The C terminus of the abundant scaffolding protein associates with the major capsid shell protein VP5 through hydrophobic interactions. After cleavage by the viral encoded protease, which removes their C-terminal 25 aa, the scaffolding proteins are released from the capsid. We have used electron cryomicroscopy and computer image processing to determine, to 13 Å, the three-dimensional structures of capsids containing either cleaved or uncleaved scaffolding proteins. Detailed comparisons show that the structures of the outer icosahedral shells are almost identical in the two capsid types. Differences are apparent in the radial distribution of the density inside the capsid shell (within a radius of 460 Å) which represents the scaffolding core. However, in both capsid types, the bulk of this internal density exhibits no icosahedral symmetry. Close examination revealed localized regions of icosahedrally arranged extra density at the interface between the outer shell and the scaffold of protease-minus capsids. Rod-like densities extending inwards for ≈40 Å from the capsid shell are present under four of the six quasi-equivalent triplex positions. Under triplexes T
b
, T
c
, and T
e
, the major additional densities appear as pairs with the rods in each pair situated 37 Å apart. We propose that these rods are formed by the C-termini of the scaffolding proteins and represent the sites of interaction between the capsid shell and scaffold.
Carbon dioxide stimulates peroxynitrite-mediated nitration of tyrosine residues and inhibits oxidation of methionine residues of glutamine synthetase: Both modifications mimic effects of adenylylation
Authors: Berlett Barbara S. , Levine Rodney L. , Stadtman Earl R.
Published: July 2002

The activity of glutamine synthetase (EC
6.3.1.2
) from
Escherichia coli
is regulated by the cyclic adenylylation and deadenylylation of Tyr-397 in each of the enzyme’s 12 identical subunits. The nitration of Tyr-397 or of the nearby Tyr-326 by peroxynitrite can convert the unadenylylated enzyme to a form exhibiting regulatory characteristics similar to the form obtained by adenylylation. The adenylylated conformation can also be elicited by the oxidation of surface-exposed methionine residues to methionine sulfoxide. However, the nitration of tyrosine residues and the oxidation of methionine residues are oppositely directed by the presence and absence of CO
2.
At physiological concentrations of CO
2
, pH 7.4, nitration occurs but oxidation of methionine residues is inhibited. Conversely, in the absence of CO
2
methionine oxidation is stimulated and nitration of tyrosine is prevented. It was further established that adenylylation of Tyr-397 precludes its nitration by peroxynitrite. Furthermore, nitration of Tyr-326 together with either nitration or adenylylation of Tyr-397 leads to inactivation of the enzyme. These results demonstrate that CO
2
can alter the course of peroxynitrite-dependent reactions and serve notice that (
i
) the reactions have physiological significance only if they are shown to occur at physiological concentrations of CO
2
and physiological pH; and (
ii
) the peroxynitrite-dependent nitration of tyrosine residues or the oxidation of methionine residues of metabolically regulated proteins can seriously compromise their biological function.
Induction of hyporesponsiveness to intact foreign protein via retroviral-mediated gene expression: The IgG scaffold is important for induction and maintenance of immune hyporesponsiveness
Authors: Kang Yubin , Melo Marco , Deng Edward , Tisch Roland , El-Amine Moustapha , Scott David W.
Published: July 2002

IgG molecules can be highly tolerogenic carriers for associated antigens. Previously, we reported that recipients of bone marrow or lipopolysaccharide-stimulated B-cell blasts, both of which were retrovirally gene-transferred with an immunodominant peptide in-frame with the variable region of a murine IgG heavy chain, were rendered profoundly unresponsive to that epitope. To further investigate whether tolerance to larger molecules can be achieved via this approach and whether the IgG scaffold is important for induction and maintenance of immunological tolerance, we engineered two retroviral constructs encoding the cI λ repressor (MBAE-1–102 and MBAE-1–102-IgG) for gene transfer. Our results show that recipients of bone marrow or peripheral B cells, transduced with the MBAE-1–102-IgG recombinant, are hyporesponsive to p1–102. In addition, the self-IgG scaffold enhanced the induction and maintenance of such an immune hyporesponsiveness. Thus, our studies demonstrate thatin vivo-expressed IgG heavy chain fusion protein can be processed and presented on the appropriate MHC class II, resulting in hyporesponsiveness to that antigen and offering an additional therapeutic approach to autoimmune diseases.
DNA methylation in transcriptional repression of two differentially expressed X-linked genes,GPC3andSYBL1
Authors: Huber Reid , Hansen R. Scott , Strazzullo Maria , Pengue Gina , Mazzarella Richard , D’Urso Michele , Schlessinger David , Pilia Giuseppe , Gartler Stanley M. , D’Esposito Maurizio
Published: July 2002

Methylation of CpG islands is an established transcriptional repressive mechanism and is a feature of silencing in X chromosome inactivation. Housekeeping genes that are subject to X inactivation exhibit differential methylation of their CpG islands such that the inactive alleles are hypermethylated. In this report, we examine two contrasting X-linked genes with CpG islands for regulation by DNA methylation:SYBL1, a housekeeping gene in the Xq pseudoautosomal region, andGPC3, a tissue-specific gene in Xq26 that is implicated in the etiology of the Simpson–Golabi–Behmel overgrowth syndrome. We observed thatin vitromethylation of either theSYBL1or theGPC3promoter resulted in repression of reporter constructs. In normal contexts, we found that both the Y and inactive X alleles ofSYBL1are repressed and hypermethylated, whereas the active X allele is expressed and unmethylated. Furthermore, the Y and inactive X alleles ofSYBL1were derepressed by treatment with the demethylating agent azadeoxycytidine.GPC3is also subject to X inactivation, and the active X allele is unmethylated in nonexpressing leukocytes as well as in an expressing cell line, suggesting that methylation is not involved in the tissue-specific repression of this allele. The inactive X allele, however, is hypermethylated in leukocytes, presumably reflecting early X inactivation events that become important for gene dosage in expressing lineages. These and other data suggest that all CpG islands on Xq, including the pseudoautosomal region, are subject to X inactivation-induced methylation. Additionally, methylation ofSYBL1on Yq may derive from a process related to X inactivation that targets large chromatin domains for transcriptional repression.
Feedback-inducible nuclear-receptor-driven reporter gene expression in transgenic mice
Authors: Mata de Urquiza Alexander , Solomin Ludmila , Perlmann Thomas
Published: July 2002

Understanding nuclear receptor signaling
in vivo
would be facilitated by an efficient methodology to determine where a nuclear receptor is active. Herein, we present a feedback-inducible expression system in transgenic mice to detect activated nuclear receptor effector proteins by using an inducible reporter gene. With this approach, reporter gene induction is not limited to a particular tissue, and, thus, this approach provides the opportunity for whole-animal screens. Furthermore, the effector and reporter genes are combined to generate a single strain of transgenic mice, which enables direct and rapid analysis of the offspring. The system was applied to localize sites where the retinoic acid receptor ligand-binding domain is activated
in vivo
. The results identify previously discovered sources of retinoids in the embryo and indicate the existence of previously undiscovered regions of retinoic acid receptor signaling
in vivo
. Notably, the feedback-inducible nuclear-receptor-driven assay, combined with an independent
in vitro
assay, provides evidence for a site of retinoid synthesis in the isthmic mesenchyme. These data illustrate the potential of feedback-inducible nuclear-receptor-driven analyses for assessing
in vivo
activation patterns of nuclear receptors and for analyzing pharmacological properties of natural and synthetic ligands of potential therapeutic value.
A first-generation X-inactivation profile of the human X chromosome
Authors: Carrel Laura , Cottle Amy A. , Goglin Karrie C. , Willard Huntington F.
Published: July 2002

In females, most genes on the X chromosome are generally assumed to be transcriptionally silenced on the inactive X as a result of X inactivation. However, particularly in humans, an increasing number of genes are known to “escape” X inactivation and are expressed from both the active (Xa) and inactive (Xi) X chromosomes; such genes reflect different molecular and epigenetic responses to X inactivation and are candidates for phenotypes associated with X aneuploidy. To identify genes that escape X inactivation and to generate a first-generation X-inactivation profile of the X, we have evaluated the expression of 224 X-linked genes and expressed sequence tags by reverse-transcription–PCR analysis of a panel of multiple independent mouse/human somatic cell hybrids containing a normal human Xi but no Xa. The resulting survey yields an initial X-inactivation profile that is estimated to represent ≈10% of all X-linked transcripts. Of the 224 transcripts tested here, 34 (three of which are pseudoautosomal) were expressed in as many as nine Xi hybrids and thus appear to escape inactivation. The genes that escape inactivation are distributed nonrandomly along the X; 31 of 34 such transcripts map to Xp, implying that the two arms of the X are epigenetically and/or evolutionarily distinct and suggesting that genetic imbalance of Xp may be more severe clinically than imbalance of Xq. A complete X-inactivation profile will provide information relevant to clinical genetics and genetic counseling and should yield insight into the genomic and epigenetic organization of the X chromosome.
Polarization transfer by cross-correlated relaxation in solution NMR with very large molecules
Authors: Riek Roland , Wider Gerhard , Pervushin Konstantin , Wüthrich Kurt
Published: July 2002

In common multidimensional NMR experiments for studies of biological macromolecules in solution, magnetization transfers via spin–spin couplings [insensitive nuclei enhanced by polarization transfer (INEPT)] are key elements of the pulse schemes. For molecular weights beyond 100,000, transverse relaxation during the transfer time may become a limiting factor. This paper presents a transfer technique for work with big molecules, cross relaxation-enhanced polarization transfer (CRINEPT), which largely reduces the size limitation of INEPT transfers with the use of cross-correlated relaxation-induced polarization transfer. The rate of polarization transfer by cross-correlated relaxation is proportional to the rotational correlation time, so that it becomes a highly efficient transfer mechanism for solution NMR with very high molecular weights. As a first implementation, [
15
N,
1
H]-correlation experiments were designed that make use of cross-correlation between dipole–dipole coupling and chemical shift anisotropy of the
15
N—
1
H-moieties for both CRINEPT and transverse relaxation-optimized spectroscopy (TROSY). When compared with INEPT-based [
15
N,
1
H]-TROSY, these experiments yielded up to 3-fold signal enhancement for amide groups of a 110,000-Da protein in aqueous solution at 4°C. CRINEPT opens avenues for solution NMR with supramolecular structures such as membrane proteins solubilized in micelles or lipid vesicles, proteins attached to nucleic acid fragments, or oligomeric proteins.
RETRACTED: Prophylactic DNA vaccine for hepatitis C virus (HCV) infection: HCV-specific cytotoxic T lymphocyte induction and protection from HCV-recombinant vaccinia infection in an HLA-A2.1 transgenic mouse model
Authors: Arichi Tatsumi , Saito Takafumi , Major Marian E. , Belyakov Igor M. , Shirai Mutsunori , Engelhard Victor H. , Feinstone Stephen M. , Berzofsky Jay A.
Published: July 2002

DNA vaccines express antigens intracellularly and effectively induce cellular immune responses. Because only chimpanzees can be used to model human hepatitis C virus (HCV) infections, we developed a small-animal model using HLA-A2.1-transgenic mice to test induction of HLA-A2.1-restricted cytotoxic T lymphocytes (CTLs) and protection against recombinant vaccinia expressing HCV-core. A plasmid encoding the HCV-core antigen induced CD8
+
CTLs specific for three conserved endogenously expressed core peptides presented by human HLA-A2.1. When challenged, DNA-immunized mice showed a substantial (5–12 log
10
) reduction in vaccinia virus titer compared with mock-immunized controls. This protection, lasting at least 14 mo, was shown to be mediated by CD8
+
cells. Thus, a DNA vaccine expressing HCV-core is a potential candidate for a prophylactic vaccine for HLA-A2.1
+
humans.
Chimeric double-stranded RNA-specific adenosine deaminase ADAR1 proteins reveal functional selectivity of double-stranded RNA-binding domains from ADAR1 and protein kinase PKR
Authors: Liu Yong , Lei Ming , Samuel Charles E.
Published: July 2002

The RNA-specific adenosine deaminase (ADAR1) and the
RNA-dependent protein kinase (PKR) are both interferon-inducible
double-stranded (ds) RNA-binding proteins. ADAR1, an RNA editing enzyme
that converts adenosine to inosine, possesses three copies of a
dsRNA-binding motif (dsRBM). PKR, a regulator of translation, has two
copies of the highly conserved dsRBM motif. To assess the functional
selectivity of the dsRBM motifs in ADAR1, we constructed and
characterized chimeric proteins in which the dsRBMs of ADAR1 were
substituted with those of PKR. Recombinant PKR-ADAR1 chimeras retained
significant RNA adenosine deaminase activity measured with a synthetic
dsRNA substrate when the spacer region between the RNA-binding and
catalytic domains of the deaminase was exactly preserved. However, with
natural substrates, substitution of the first two dsRBMs of ADAR1 with
those from PKR dramatically reduced site-selective editing activity at
the R/G and (+)60 sites of the glutamate receptor B subunit pre-RNA
and completely abolished editing of the serotonin 2C receptor
(5-HT
2C
R) pre-RNA at the A site. Chimeric deaminases
possessing only the two dsRBMs from PKR were incapable of editing
either glutamate receptor B subunit or 5-HT
2C
R natural
sites but edited synthetic dsRNA. Finally, RNA antagonists of PKR
significantly inhibited the activity of chimeric PKR-ADAR1 proteins
relative to wild-type ADAR1, further demonstrating the functional
selectivity of the dsRBM motifs.
An unexpectedly high excision capacity for mispaired 5-hydroxymethyluracil in human cell extracts
Authors: Rusmintratip Valaiporn , Sowers Lawrence C.
Published: July 2002

The oxidation of thymine in DNA can generate a base pair between
5-hydroxymethyluracil (HmU) and adenine, whereas the oxidation and
deamination of 5-methylcytosine (5mC) in DNA can generate a base pair
between HmU and guanine. Using synthetic oligonucleotides containing
HmU at a defined site, HmU-DNA glycosylase activities in HeLa cell and
human fibroblast cell extracts have been observed. An HmU-DNA
glycosylase activity that removes HmU mispaired with guanine has been
measured. Surprisingly, the HmU:G excision activity is 60 times greater
than the corresponding HmU:A activity, even though the expected rate of
formation of the HmU:A base pair exceeds that of the HmU:G base pair by
a factor of 10
7
. The HmU:G mispair would arise from the
5mC:G base pair, and, if unrepaired, would give rise to a transition
mutation. The observation of an unexpectedly high HmU:G glycosylase
activity suggests that human cells may encounter the HmU:G mispair much
more frequently than expected. The conversion of 5mC to HmU must be
considered as a potential pathway for the generation of 5mC to T
transition mutations, which are often found in human tumors.
CD40-CD40L independent Ig gene hypermutation suggests a second B cell diversification pathway in humans
Authors: Weller Sandra , Faili Ahmad , Garcia Corinne , Braun Moritz C. , Le Deist Françoise , de Saint Basile Geneviève , Hermine Olivier , Fischer Alain , Reynaud Claude-Agnès , Weill Jean-Claude
Published: July 2002

Somatically mutated IgM+-only and IgM+IgD+CD27+B lymphocytes comprise ≈25% of the human peripheral B cell pool. These cells phenotypically resemble class-switched B cells and have therefore been classified as postgerminal center memory B cells. X-linked hyper IgM patients have a genetic defect characterized by a mutation of theCD40Lgene. These patients, who do not express a functional CD40 ligand, cannot switch Ig isotypes and do not form germinal centers and memory B cells. We report here that an IgM+IgD+CD27+B cell subset with somatically mutated Ig receptors is generated in these patients, implying that these cells expand and diversify their Ig receptors in the absence of classical cognate T–B collaboration. The presence of this sole subset in the absence of IgM+-only and switched CD27+memory B cells suggests that it belongs to a separate diversification pathway.
Uterine Leiomyomas: Mechanisms of Tumorigenesis
Authors: Houston Kevin D. , Hunter Deborah S. , Hodges Leslie C. , Walker Cheryl L.
Published: July 2002

Uterine leiomyomas, also called fi broids, are the most common reproductive tract neoplasm and the leading indication for hysterectomy in premenopausal women. The discovery and development of medicinal therapies for uterine leiomyoma have been hampered by a lack of understanding regarding the etiology and molecular mechanisms underlying the development of these lesions. Although the estrogen responsiveness of uterine leiomyoma is well established, the impact of environmental estrogens and their contribution to the development of these tumors is currently unknown. The Eker rat model of uterine leiomyoma has proven useful for addressing these issues and understanding the pathophysiology of this disease. The Eker rat is the only animal model that develops spontaneous uterine leiomyomas, and these tumors share many characteristics with those found in humans. The availability of tumor-derived cell lines from these rats has made this a valuable in vitro/in vivo model system for experimental studies to investigate molecular mechanisms of disease and to design interventional and preventative strategies for this clinically relevant tumor.
Elevated Liver Enzyme Levels in Opioid‐Dependent Patients with Hepatitis Treated with Buprenorphine
Authors: Petry Nancy M. , Bickel Warren K. , Piasecki Dana , Marsch Lisa A. , Badger Gary J.
Published: July 2002

The purpose of this study was to assess changes in liver enzyme levels among opioid‐dependent patients treated with buprenorphine. Liver enzyme levels were evaluated among 120 individuals before treatment and following a minimum of 40 days of buprenorphine treatment (2, 4, or 8 mg/70 kg/day) . Among patients with a history of hepatitis, AST and ALT levels significantly increased (p < .05) with buprenorphine treatment. The odds of observing an increase in AST were determined to be dependent upon buprenorphine dose (p < .05; odds ratio = 1.23 per 1 mg increase in dose) . These results suggest that liver enzyme levels should be monitored carefully when patients with hepatitis are treated with buprenorphine.
Large Animal Toxicology: Introduction and General Principles
Authors: Gad Shayne C.
Published: July 2002

Large animal toxicity studies, also called nonrodent studies, are very different from rodent (rat, mouse, guinea pig, and rabbit) studies in significant ways. The differences between the two study types, as well as the advantages and disadvantages of each, are evaluated in detail. Also examined are causes for selecting specific species, regulatory requirements for using nonrodent species, and an overview of major species characteristics for dogs, primates, pigs, and ferrets.
Peroral Subchronic, Chronic Toxicity, and Pharmacokinetic Studies of a 100-KiIodaIton Polymer of Ethylene Oxide (Polyox N-10) in the Fischer 344 Rat
Authors: Leung Hon-Wing , Ballantyne Bryan , Hermansky Steven J. , Frantz Stephen W.
Published: July 2002

Polyox Water Soluble Resins (CAS No. 25322–68–3) are high-molecular-weight polymers of ethylene oxide in a variety of viscosity grades. They are widely used in cosmetic formulations, as pharmaceutical excipients, and food contact applications. The potential for absorption and long-term toxicity (including oncogenicity) from peroral dosing was investigated using an N-10 grade with an average molecular weight of about 100,000 daltons. A subchronic (13-week) toxicity study with up to 3% Polyox N-10 in the diet of Fischer 344 rats showed slight increases in food consumption, body weight, and body weight gain. A dose-related increase in liver weight was observed, but this was not associated with any histopathology, and morphometric analysis showed no alteration in the number or size of the hepatocytes. Because of the lack of correlative pathology findings, the liver weight increase was considered not to be deleterious, but a secondary response to increased food consumption. A chronic (2-year) toxicity/oncogenicity study with up to 2% Polyox N-10 in the diet of Fischer 344 rats showed no effect with respect to clinical signs, body and organ weights, clinical pathology, urinalysis, and neoplastic and non-neoplastic pathology. Pharmacokinetic and material balance studies showed essentially complete recoveries (99% in males, 104% in females) from the excreta, with nearly all the radiolabel being eliminated in the feces (98% in males, 101% in females) in Fischer 344 rats given an oral dose of 14C-labelled Polyox N-10. Recoveries from the urine, expired air, blood, and other tissues were negligible (<1%). In conclusion, Polyox N-10 given orally is not absorbed from the gastrointestinal tract, and does not produce long-term and chronic toxicity, including oncogenicity.
Effects of Subchronic Exposure to Manganese Chloride on Tissue Distribution of Three Essential Elements in Rats
Authors: Missy Pascale , Lanhers Marie-Claire , Cunat Lisiane , Joyeux Michel , Burnel Daniel
Published: July 2002

A subchronic treatment of manganese chloride (MnCl2) was administered to rats by intraperitoneal (IP) route (6 mg Mn/kg of body weight/day) or oral (PO) route (75 mg Mn/kg of body weight/day) for 4 weeks. After a 2-week interval, different tissues plus the blood were sampled. An increase of manganese (Mn) concentrations was observed in most of the tissues, particularly in the nervous system (brain and spinal cord) and in femur, with the exception of liver, adrenal glands, and esophagus by IP treatment and liver, jejunum, ileum, and adipose tissue by PO treatment. Tissue accumulation of Mn was greater by IP treatment. During each of the two treatments, urinary and fecal excretion of Mn increased. The presence of Mn observed in whole blood, bone marrow, and spleen after IP treatment could be explained by the existence of competition between iron (Fe) and Mn that may appear, notably, as a disturbance in the functioning of the respiratory chain in the cells (incomplete O2 reduction and formation of free radicals and oxygenated compounds), leading to cellular degeneration. In these experimental conditions, no obvious competition could be observed with zinc (Zn) and copper (Cu). Despite a large accumulation of Mn in the bones, no disturbance of the phosphorus-calcium metabolism was observed.
Effect of 2,3,7,8-Tetrachloro-di-benzo-p-dioxin on T Cell Subpopulations in the Thymus and Spleen of Mice with Chronic Toxoplasma gondii Infection
Authors: King Marquea D. , Lindsay David S. , Ehrich Marion F. , Nagarkatti Mitzi
Published: July 2002

In the current study, the effect of exposure to the environmental pollutant, 2,3,7,8-tetrachloro-di-benzo- p-dioxin (TCDD), on mice having chronic infection with Toxoplasma gondii was investigated. For this purpose, four groups of mice were used—mice treated with vehicle, mice treated with TCDD alone, mice infected with T. gondii alone, and mice receiving a combination of TCDD treatment and T. gondii infection. Histological examination and tissue cyst enumeration were performed to indicate the level of infection of the brain. The immune status was studied by enumerating the cellularity as well as the percentages and absolute numbers of the lymphocyte subsets based on the expression of CD4 and CD8 markers in the thymus and spleen. Our studies demonstrated that there was a significant decrease in the total number of thymocytes in TCDD-treated mice that were either uninfected or infected with T. gondii when compared to vehicle controls. However, there was no significant difference observed in thymic cellularity in mice that were infected with T. gondii alone when compared to the uninfected vehicle controls. In addition, the ratio and the total numbers of CD4+, CD8+, CD4–CD8–(double negative, DN) and CD4+CD8+ (double positive, DP) T cell subsets in the thymus from various groups were determined. There was no change in the percentages of T cell subsets in TCDD-treated mice or T. gondii-infected mice when compared to the vehicle controls. However, there was a decrease in the percentage of DPT cells and an increase in the DN and CD8+ T cells in mice that received a combination of TCDD-treatment and T. gondii infection when compared to mice receiving the vehicle or TCDD-treatment alone or infection with T. gondii alone. There was also a decrease in the absolute numbers of the DP and CD4+ T cells and an increase in the CD8+ T cells in the thymus of mice receiving the combination of TCDD-treatment and T. gondii infection when compared to vehicle controls. The splenic cellularity as well as the percentage and absolute numbers of the CD4+ and CD8+ T cell subsets and the non-T cells were not altered in all the groups tested. The natural history of T. gondii infection was not altered following TCDD treatment as demonstrated by no significant differences in brain lesion scores and the number of tissue cysts in the brains of these mice.
Topical Permethrin Exposure Causes Thymic Atrophy and Persistent Inhibition of the Contact Hypersensitivity Response in C57BI/6 Mice
Authors: Punareewattana Korawuth , Smith Bonnie J. , Blaylock Benny L. , Robertson John L. , Gogal Robert M. , Prater M. Renee , Longstreth Janice , Snodgrass Hubert L. , Holladay Steven D.
Published: July 2002

Permethrin was applied to the shaved dorsal interscapular region of female C57B1/6 mice at doses of 0.5 or 1.5 θ 1/day in corn oil and neat 5.0 θ 1/day. These doses corresponded to approximately 22, 66, and 220 mg/kg/day topical permethrin. Mice were exposed in this manner either daily for 10 or 30 consecutive days, or every other day for 7 or 14 exposures. Body weight was not affected by any of the treatment regimens. However, thymic weight was decreased and splenic weight was increased by 1.5 or 5.0 θ1 permethrin/day, 2 days after termination of 10 consecutive days of topical chemical exposure. Cell surface antigen expression did not change in any treatment group on thymocytes (CD4, CD8), splenocytes (CD45R, Thy 1.2), or bone marrow cells (CD45, CD45R). A persistent, dose-related inhibition of the contact hypersensitivity (CH) response occurred in mice at all exposure levels of permethrin tested.
Polyamine Protection Against Chemically Induced Hepatotoxicity
Authors: Mbonifor John N. , Chigbo Francis E. , Mehendale Harihara M.
Published: July 2002

The protective effect of putrescine (a polyamine) on chemically induced hepatotoxicity in male Sprague-Dawley rats was assessed by mortality, clinical pathological changes (specifically alanine aminotransferase and aspartate aminotransferase activities), and liver histopathological changes. A reduction in hepatotoxicant-induced mortality by 20% to 25% was observed when putrescine (100 mg/kg/day) was administered intraperitoneally for 3 days prior to hepatotoxicant administration (either carbon tetrachloride or allyl alcohol at dose levels approximating the LD50). Putrescine significantly reduced the hepatoxicant-induced increases in serum alanine aminotransferase and aspartate aminotransferase activities. Histological assessment revealed that putrescine pretreatment also reduced the severity and frequency of hepatotoxicant-induced liver necrosis. Administration of putrescine at 0.5 and 3 hours following hepatotoxicant treatment decreased both hepatoxicant-induced mortality and hepatoxicant-induced increases in serum alanine aminotransferase and aspartate aminotransferase activities, with the 0.5 hour postdose treatment being more effective than the 3 hours postdose treatment. Early intervention reduced the mortality rate in the allyl alcohol plus putrescine group by 20% and by 10% in the carbon tetrachloride as well as the carbon tetrachloride plus putrescine groups. However, the effectiveness of postdose putrescine treatment was less than when putrescine was administered prior to the hepatotoxicant.
Photobiology/Photochemistry
Authors: Coohill Thomas P.
Published: July 2002

Exposure of living organisms to non-ionizing electromagnetic radiation (here confined to the visible and part of the ultraviolet, 200-800 nm) can cause a toxic reaction. The details of the exposure, both in intensity and wavelength composition, will determine the degree of effect. If absorbing chromophores, both endogenous and exogenous, are present, additional response can be elicited. Whether the radiation reaches a sensitive target will depend upon the depth of penetration and the opacity of the cell or tissue. The final effect will be determined by the initial photoproducts produced, the subsequent reactions they cause, and the amount of repair of damage by cellular processes. In some cases it is possible to predict the complete response; in others it is variable.
In Vitro Assays for Phototoxicity
Authors: Kornhauser A. , Wei R. R. , Warner W. G.
Published: July 2002

This paper summarizes a few in vitro methods to assess photodamage in cells irradiated with UV of various wavelengths in the presence of a number of photo-sensitizers. A single in vitro assay for phototoxicity (photoirritation) is not likely to be predictive because of different mechanisms of phototoxicity and diverse cellular targets for injury. A number of methods have to be combined to provide a better prediction of these phenomena. Measurement of mechanistically relevant biomarkers also represents a promising area of in vitro testing for phototoxicity, and it is also briefly reviewed in this paper. Photodynamic sensitizers, representing a large class of phototoxic agents, can now be identified by sensitive measurement of photooxidative damage to cellular RNA and DNA. Currently, US government agencies have not identified a single in vitro assay for phototoxicity which would be acceptable for replacing an in vivo assay for regulatory purposes.
PROTECTING THE LONG-TERM UNEMPLOYED
Authors: Gutiérrez Rodolfo , Guillén Ana M.
Published: July 2002

Long-term unemployment (LTU) affects the Spanish labour market to a broader extent than those of other European Union members. This article analyses the choices made within the Spanish welfare state in order to protect the long-term unemployed. Indeed, a significant policy shift entailing redefinition of targets and incentives may be ascertained over the past twenty years. The article aims to explain why such a shift was possible by using a neoinsitutionalist theoretical perspective. After discussing the neo-insitutionalist approach to the study of labour markets, the article considers the evolution of LTU in a comparative perspective as well as the characteristics of the longterm unemployed in Spain, who present peculiar characteristics in terms of sex and age. It then assesses the evolution of labour market policies, i.e. to analyse the policy reform process by taking into account the perceptions and positions of the different actors involved. The article concludes that policy legacies and path dependency (i.e. reliance on passive protection) are indeed hard to overcome, even in the case of a national state where the problem of long-term unemployment is of crucial importance. Thus a major change in ‘shared meanings’ among policy-actors was needed for success in the adoption (and adaptation) of new policy paradigms in Spain. Furthermore, the impact of new policies on the reduction of LTU has been limited, and different groups of long-term unemployed have profited unevenly from them.
RELIABILITY AT RISK: The supervision of financial models as a case study for reflexive economic sociology
Authors: Izquierdo A. Javier
Published: July 2002

This article focuses on financial ‘model risk’ supervision as a test case for a reflexive approach to the sociology of contemporary financial markets. Model risk is customarily defined as a statistically significant relation between the expectation of a trading loss by a firm and its strategic use of, somehow flawed, econometric models for asset pricing and market trading purposes. It made its first public appearance in the mid-1990s, as a component of a new generation of financial risk management systems for the financial derivatives industry. Since then it has been assimilated by the most sophisticated national and international financial regulatory bodies. A perfect illustration of the thesis of the progressive ‘embedding of the economy into economics’, the forensic practice of financial reliability trials (backtesting) faces a deep pragmatic dilemma: how to distinguish truly unpredictable error from negligent risk management behaviour in a wildly randomized social environment.
THE CONSTRUCTION OF A MARKET: A frame analysis of the liberalization of the electricity market in the European Union
Authors: Nylander Johan
Published: July 2002

This article examines a specific case of policy-making in the European Union, the liberalization of electricity. This case illustrates the shortcomings of traditional realist and rational choice approaches to the study of political processes. Drawing on empirical research and utilizing analytical tools from the sociological cultural institutionalism and social movements studies, the article identifies and analyses cultural frames and the transformation of these in order to interpret the changes in the European electricity policy domain, changes that traditional realist and neofunctionalist approaches could not predict. The article brings out the importance of an elite bureaucratic movement that is able to frame and reframe issues within the borders of existing cultural master frames. It is also shown how transformation of frames affects the structure of interest groups at the European level.
Social exclusion, children and education: Implications of a rights-based approach
Authors: Klasen Stephan
Published: July 2002

In this paper, I am applying a rights-based approach to childhood social exclusion that, following Sen's capability approach as one formulation of such a rights-based approach, sees social exclusion as the failure of people to have access to critical capabilities relating to their integration into society. The implications of this approach will then be applied to the relation between education and social exclusion, where it is shown that education has a critical impact on mitigating or reinforcing social exclusion. Taking such a capabilities-based approach implies a shift away from a concentration on average achievement generated by an education system to the low end of the achievement distribution and the ability of the education system to raise the performance and integrate the most disadvantaged students. The paper investigates how education systems in Europe and other industrialized countries are achieving this goal.
Female employment differences, poverty and care provisions
Authors: Cantillon Bea , Ghysels Joris , Mussche Ninke , Van Dam Rudi
Published: July 2002

In this article, we link an analysis of female employment in the OECD with a reflection on the role of the welfare state regarding the provision of care. First, we reveal a picture of multi-speed labour market participation, with highly skilled women approaching male employment rates irrespective of the type of welfare state and low-skilled women lagging considerably behind, especially in the conservative welfare states. We also show that the gaps between the sexes, educational groups and countries grow even wider among women with children. Consequently, dual earnership is far from generalized in the OECD and differences in poverty rates may be explained by (among other factors) the uneven participation in paid labour of women. To counteract this phenomenon, we therefore plea for a welfare state reform towards the inclusion of care. This will ease the entry to paid employment for mothers and low-skilled women, and thus act as a poverty reduction strategy. A combination of several policy measures is suggested.
Transport of a Large Oligomeric Protein by the Cytoplasm to Vacuole Protein Targeting Pathway
Authors: Kim John , Scott Sidney V. , Oda Michael N. , Klionsky Daniel J.
Published: July 2002

Aminopeptidase I (API) is transported into the yeast vacuole by the cytoplasm to vacuole targeting (Cvt) pathway. Genetic evidence suggests that autophagy, a major degradative pathway in eukaryotes, and the Cvt pathway share largely the same cellular machinery. To understand the mechanism of the Cvt import process, we examined the native state of API. Dodecameric assembly of precursor API in the cytoplasm and membrane binding were rapid events, whereas subsequent vacuolar import appeared to be rate limiting. A unique temperature-sensitive API-targeting mutant allowed us to kinetically monitor its oligomeric state during translocation. Our findings indicate that API is maintained as a dodecamer throughout its import and will be useful to study the posttranslational movement of folded proteins across biological membranes.
Chromosome Association of Minichromosome Maintenance Proteins in Drosophila Mitotic Cycles
Authors: Su Tin Tin , O'Farrell Patrick H.
Published: July 2002

Minichromosome maintenance (MCM) proteins are essential DNA replication factors conserved among eukaryotes. MCMs cycle between chromatin bound and dissociated states during each cell cycle. Their absence on chromatin is thought to contribute to the inability of a G2 nucleus to replicate DNA. Passage through mitosis restores the ability of MCMs to bind chromatin and the ability to replicate DNA. In Drosophila early embryonic cell cycles, which lack a G1 phase, MCMs reassociate with condensed chromosomes toward the end of mitosis. To explore the coupling between mitosis and MCM–chromatin interaction, we tested whether this reassociation requires mitotic degradation of cyclins. Arrest of mitosis by induced expression of nondegradable forms of cyclins A and/or B showed that reassociation of MCMs to chromatin requires cyclin A destruction but not cyclin B destruction. In contrast to the earlier mitoses, mitosis 16 (M16) is followed by G1, and MCMs do not reassociate with chromatin at the end of M16. dacapo mutant embryos lack an inhibitor of cyclin E, do not enter G1 quiescence after M16, and show mitotic reassociation of MCM proteins. We propose that cyclin E, inhibited by Dacapo in M16, promotes chromosome binding of MCMs. We suggest that cyclins have both positive and negative roles in controlling MCM–chromatin association.
Mannose 6-Phosphate/Insulin-like Growth Factor–II Receptor Targets the Urokinase Receptor to Lysosomes via a Novel Binding Interaction
Authors: Nykjær Anders , Christensen Erik I. , Vorum Henrik , Hager Henrik , Petersen Claus M. , Røigaard Hans , Min Hye Y. , Vilhardt Frederik , Møller Lisbeth B. , Kornfeld Stuart , Gliemann Jørgen
Published: July 2002

The urokinase-type plasminogen activator receptor (uPAR) plays an important role on the cell surface in mediating extracellular degradative processes and formation of active TGF-β, and in nonproteolytic events such as cell adhesion, migration, and transmembrane signaling. We have searched for mechanisms that determine the cellular location of uPAR and may participate in its disposal. When using purified receptor preparations, we find that uPAR binds to the cation-independent, mannose 6-phosphate/insulin-like growth factor–II (IGF-II) receptor (CIMPR) with an affinity in the low micromolar range, but not to the 46-kD, cation-dependent, mannose 6-phosphate receptor (CDMPR). The binding is not perturbed by uPA and appears to involve domains DII + DIII of the uPAR protein moiety, but not the glycosylphosphatidylinositol anchor. The binding occurs at site(s) on the CIMPR different from those engaged in binding of mannose 6-phosphate epitopes or IGF-II. To evaluate the significance of the binding, immunofluorescence and immunoelectron microscopy studies were performed in transfected cells, and the results show that wild-type CIMPR, but not CIMPR lacking an intact sorting signal, modulates the subcellular distribution of uPAR and is capable of directing it to lysosomes. We conclude that a site within CIMPR, distinct from its previously known ligand binding sites, binds uPAR and modulates its subcellular distribution.
Suppression of Radixin and Moesin Alters Growth Cone Morphology, Motility, and Process Formation In Primary Cultured Neurons
Authors: Paglini Gabriela , Kunda Patricia , Quiroga Santiago , Kosik Kenneth , Cáceres Alfredo
Published: July 2002

In this study we have examined the cellular functions of ERM proteins in developing neurons. The results obtained indicate that there is a high degree of spatial and temporal correlation between the expression and subcellular localization of radixin and moesin with the morphological development of neuritic growth cones. More importantly, we show that double suppression of radixin and moesin, but not of ezrin–radixin or ezrin–moesin, results in reduction of growth cone size, disappearance of radial striations, retraction of the growth cone lamellipodial veil, and disorganization of actin filaments that invade the central region of growth cones where they colocalize with microtubules. Neuritic tips from radixin–moesin suppressed neurons displayed high filopodial protrusive activity; however, its rate of advance is 8–10 times slower than the one of growth cones from control neurons. Radixin–moesin suppressed neurons have short neurites and failed to develop an axon-like neurite, a phenomenon that appears to be directly linked with the alterations in growth cone structure and motility. Taken collectively, our data suggest that by regulating key aspects of growth cone development and maintenance, radixin and moesin modulate neurite formation and the development of neuronal polarity.
γ-Synergin
Authors: Page Lesley J. , Sowerby Penelope J. , Lui Winnie W.Y. , Robinson Margaret S.
Published: July 2002

The AP-1 adaptor complex is associated with the TGN, where it links selected membrane proteins to the clathrin lattice, enabling these proteins to be concentrated in clathrin-coated vesicles. To identify other proteins that participate in the clathrin-coated vesicle cycle at the TGN, we have carried out a yeast two- hybrid library screen using the γ-adaptin subunit of the AP-1 complex as bait. Two novel, ubiquitously expressed proteins were found: p34, which interacts with both γ-adaptin and α-adaptin, and γ-synergin, an alternatively spliced protein with an apparent molecular mass of ∼110–190 kD, which only interacts with γ-adaptin. γ-Synergin is associated with AP-1 both in the cytosol and on TGN membranes, and it is strongly enriched in clathrin-coated vesicles. It binds directly to the ear domain of γ-adaptin and it contains an Eps15 homology (EH) domain, although the EH domain is not part of the γ-adaptin binding site. In cells expressing α-adaptin with the γ-adaptin ear, a construct that goes mainly to the plasma membrane, much of the γ-synergin is also rerouted to the plasma membrane, indicating that it follows AP-1 onto membranes rather than leading it there. The presence of an EH domain suggests that γ-synergin links the AP-1 complex to another protein or proteins.
Protein Tyrosine Phosphatase α (Ptpα) and Contactin Form a Novel Neuronal Receptor Complex Linked to the Intracellular Tyrosine Kinase Fyn
Authors: Zeng Li , D'Alessandri Luca , Kalousek Markus B. , Vaughan Lloyd , Pallen Catherine J.
Published: July 2002

Glycosyl phosphatidylinositol (GPI)–linked receptors and receptor protein tyrosine phosphatases (RPTPs), both play key roles in nervous system development, although the molecular mechanisms are largely unknown. Despite lacking a transmembrane domain, GPI receptors can recruit intracellular src family tyrosine kinases to receptor complexes. Few ligands for the extracellular regions of RPTPs are known, relegating most to the status of orphan receptors. We demonstrate that PTPα, an RPTP that dephosphorylates and activates src family kinases, forms a novel membrane-spanning complex with the neuronal GPI-anchored receptor contactin. PTPα and contactin associate in a lateral (cis) complex mediated through the extracellular region of PTPα. This complex is stable to isolation from brain lysates or transfected cells through immunoprecipitation and to antibody-induced coclustering of PTPα and contactin within cells. This is the first demonstration of a receptor PTP in a cis configuration with another cell surface receptor, suggesting an additional mode for regulation of a PTP. The transmembrane and catalytic nature of PTPα indicate that it likely forms the transducing element of the complex, and we postulate that the role of contactin is to assemble a phosphorylation-competent system at the cell surface, conferring a dynamic signal transduction capability to the recognition element.