bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of chloroplast protein import through a protochlorophyllide-responsive transit peptide
Authors: Reinbothe Christiane , Lebedev Nikolai , Apel Klaus , Reinbothe Steffen
Published: July 2002

NADPH:protochlorophyllide (Pchlide) oxidoreductase (POR) is the key enzyme of chlorophyll biosynthesis in angiosperms. In barley, two POR enzymes, termed PORA and PORB, exist. Both are nucleus-encoded plastid proteins that must be imported posttranslationally from the cytosol. Whereas the import of the precursor of PORA, pPORA, previously has been shown to depend on Pchlide, the import of pPORB occurred constitutively. To study this striking difference, chimeric precursor proteins were constructed in which the transit sequences of the pPORA and pPORB were exchanged and fused to either their cognate polypeptides or to a cytosolic dihydrofolate reductase (DHFR) reporter protein of mouse. As shown here, the transit peptide of the pPORA (transA) conferred the Pchlide requirement of import onto both the mature PORB and the DHFR. By contrast, the transit peptide of the pPORB directed the reporter protein into both chloroplasts that contained or lacked translocation-active Pchlide.In vitrobinding studies further demonstrated that the transit peptide of the pPORA, but not of the pPORB, is able to bind Pchlide. We conclude that the import of the authentic pPORA and that of the transA-PORB and transA-DHFR fusion proteins is regulated by a direct transit peptide-Pchlide interaction, which is likely to occur in the plastid envelope, a major site of porphyrin biosynthesis.
ATPases and phosphate exchange activities in magnesium chelatase subunits of
Rhodobacter sphaeroides
Authors: Hansson Mats , Kannangara C. Gamini
Published: July 2002

Three separate proteins, BchD, BchH, and BchI, together with ATP, insert magnesium into protoporphyrin IX. An analysis of ATP utilization by the subunits revealed the following: BchH catalyzed ATP hydrolysis at the rate of 0.9 nmol per min per mg of protein. BchI and BchD, tested individually, had no ATPase activity but, when combined, hydrolyzed ATP at the rate of 117.9 nmol/min per mg of protein. Magnesium ions were required for the ATPase activities of both BchH and BchI+D, and these activities were inhibited 50% by 2 mM
o
-phenanthroline. BchI additionally catalyzed a phosphate exchange reaction from ATP and ADP. We conclude that ATP hydrolysis by BchI+D is required for an activation step in the magnesium chelatase reaction, whereas ATPase activity of BchH and the phosphate exchange activity of BchI participate in subsequent reactions leading to the insertion of Mg
2+
into protoporphyrin IX.
Both hypertrophic and dilated cardiomyopathies are caused by mutation of the same gene, δ-sarcoglycan, in hamster: An animal model of disrupted dystrophin-associated glycoprotein complex
Authors: Sakamoto Aiji , Ono Kageyoshi , Abe Makoto , Jasmin Gaëten , Eki Toshihiko , Murakami Yasufumi , Masaki Tomoh , Toyo-oka Teruhiko , Hanaoka Fumio
Published: July 2002

Cardiomyopathy (CM) is a primary degenerative disease of myocardium and is traditionally categorized into hypertrophic and dilated CMs (HCM and DCM) according to its gross appearance. Cardiomyopathic hamster (CM hamster), a representative model of human hereditary CM, has HCM and DCM inbred sublines, both of which descend from the same ancestor. Herein we show that both HCM and DCM hamsters share a common defect in a gene for δ-sarcoglycan (δ-SG), the functional role of which is yet to be characterized. A breakpoint causing genomic deletion was found to be located at 6.1 kb 5′ upstream of the second exon of δ-SG gene, and its 5′ upstream region of more than 27.4 kb, including the authentic first exon of δ-SG gene, was deleted. This deletion included the major transcription initiation site, resulting in a deficiency of δ-SG transcripts with the consequent loss of δ-SG protein in all the CM hamsters, despite the fact that the protein coding region of δ-SG starting from the second exon was conserved in all the CM hamsters. We elucidated the molecular interaction of dystrophin-associated glycoproteins including δ-SG, by using an
in vitro
pull-down study and ligand overlay assay, which indicates the functional role of δ-SG in stabilizing sarcolemma. The present study not only identifies CM hamster as a valuable animal model for studying the function of δ-SG
in vivo
but also provides a genetic target for diagnosis and treatment of human CM.
Structural model of cytochrome
b
559
in photosystem II based on a mutant with genetically fused subunits
Authors: McNamara Vincent P. , Sutterwala Fayyaz S. , Pakrasi Himadri B. , Whitmarsh John
Published: July 2002

Photosystem II is a reaction center protein complex located in photosynthetic membranes of plants, algae, and cyanobacteria. Using light energy, photosystem II catalyzes the oxidation of water and the reduction of plastoquinone, resulting in the release of molecular oxygen. A key component of photosystem II is cytochrome
b
559
, a membrane-embedded heme protein with an unknown function. The cytochrome is unusual in that a heme links two separate polypeptide subunits, α and β, either as a heterodimer (αβ) or as two homodimers (α
2
and β
2
). To determine the structural organization of cytochrome
b
559
in the membrane, we used site-directed mutagenesis to fuse the coding regions of the two respective genes in the cyanobacterium
Synechocystis
sp. PCC 6803. In this construction, the C terminus of the α subunit (9 kDa) is attached to the N terminus of the β subunit (5 kDa) to form a 14-kDa αβ fusion protein that is predicted to have two membrane-spanning α-helices with antiparallel orientations. Cells containing the αβ fusion protein grow photoautotrophically and assemble functional photosystem II complexes. Optical spectroscopy shows that the αβ fusion protein binds heme and is incorporated into photosystem II. These data support a structural model of cytochrome
b
559
in which one heme is coordinated to an α
2
homodimer and a second heme is coordinated to a β
2
homodimer. In this model, each photosystem II complex contains two cytochrome
b
559
hemes, with the α
2
heme located near the stromal side of the membrane and the β
2
heme located near the lumenal side.
Differential display of genome subsets containing specific interspersed repeats
Authors: Broude Natalia E. , Chandra Abha , Smith Cassandra L.
Published: July 2002

A genomic differential display method was developed that analyzes many restriction fragment length polymorphisms simultaneously. Interspersed repeat sequences were used to reduce DNA sample complexity and to target genomic subsets of interest. This work focused on trinucleotide repeats because of their importance in human inherited diseases. Immobilized repeat-containing oligonucleotides were used to capture genomic DNA fragments containing sequences complementary to the oligonucleotide. Captured fragments were amplified by PCR and fluorescently labeled using primers complementary to the repeat sequence and/or to the known sequences ligated to the ends of the restriction fragments. The labeled PCR fragments were displayed by size on a high-resolution automated fluorescent DNA sequencing instrument. Although there was a conservation in the overall pattern of displayed genome subsets, many clear and reproducible differences were detected when genomes from different individuals were compared. Fewer differences were detected within, than between, monozygotic twin pair genomes. In control experiments, the method distinguished between Huntington disease alleles with normal and expanded CAG repeat lengths.
Contributions of cell kill and posttreatment tumor growth rates to the repopulation of intracerebral 9L tumors after chemotherapy: An MRI study
Authors: Ross Brian D. , Zhao Yong-Jie , Neal Eric R. , Stegman Lauren D. , Ercolani Matthew , Ben-Yoseph Oded , Chenevert Thomas L.
Published: July 2002

The drought of progress in clinical brain tumor therapy provides an impetus for developing new treatments as well as methods for testing therapeutics in animal models. The inability of traditional assays to simultaneously measure tumor size, location, growth kinetics, and cell kill achieved by a treatment complicates the interpretation of therapy experiments in animal models. To address these issues, tumor volume measurements obtained from serial magnetic resonance images were used to noninvasively estimate cell kill values in individual rats with intracerebral 9L tumors after treatment with 0.5, 1, or 2 × LD
10
doses of 1,3-bis(2-chloroethyl)-1-nitrosourea. The calculated cell kill values were consistently lower than those reported using traditional assays. A dose-dependent increase in 9L tumor doubling time after treatment was observed that significantly contributed to the time required for surviving cells to repopulate the tumor mass. This study reveals that increases in animal survival are not exclusively attributable to the fraction of tumor cells killed but rather are a function of the cell kill and repopulation kinetics, both of which vary with treatment dose.
α-Fetoprotein gene sequences mediating
Afr2
regulation during liver regeneration
Authors: Jin David K. , Vacher Jean , Feuerman Miriam H.
Published: July 2002

α-fetoprotein (AFP) gene expression occurs in the yolk sac, in the fetal liver and gut, and in the adult liver during regeneration and tumorigenesis. Two unlinked genes determine the level of AFP gene expression in adult mice:
Afr1
regulates the basal level of expression in the normal adult liver, and
Afr2
regulates the increase in expression during liver regeneration. It has been shown that AFP-derived transgenes, including the sequences between −1,010 and −838 bp and between −118 bp and the transcriptional start site were induced appropriately during liver regeneration and were
Afr2
-regulated. To assess the role of the distal sequence in gene expression during liver regeneration, a new transgene with 7.6 kilobases of 5′-flanking sequence deleted between −1,010 and −838 bp was designed. We show that this transgene was subject to characteristic AFP tissue-specific and developmental regulation, in that it was highly expressed in the yolk sac and the fetal liver and gut but not in normal adult tissues. Expression was induced in response to liver regeneration as observed for the endogenous gene. The genetic regulation of the basal level of AFP gene expression in adult liver by the
Afr1
gene was undisturbed. However, transgene expression was not regulated by
Afr2
during liver regeneration. Our data suggest that
Afr2
regulation of AFP gene expression during liver regeneration requires the sequence between −1,010 and −838 bp and is independent of other regulatory mechanisms.
A potential mediator of collagenous block copolymer gradients in mussel byssal threads
Authors: Qin Xiao-Xia , Waite J. Herbert
Published: July 2002

Mussel byssal threads contain unusual block copolymer-like proteins that combine collagen with flanking domains that resemble silk-fibroin (preCol-D) or elastin (preCol-P). These are distributed in complementary gradients along the length of the threads and as precursors in the mussel foot. We discuss a 76-kDa precursor, preCol-NG, from a cDNA library of the foot where it has no gradient but rather is distributed evenly along the distal to proximal axis. A pepsin-resistant fragment of preCol-NG has been confirmed in byssal threads. Like preCol-D and -P, this protein has a central collagenous domain, flanking domains, an acidic patch, and histidine-rich termini. The flanking domains of preCol-NG resemble the glycine-rich proteins of plant cell walls with tandem XGly
n
repeats where X denotes alanine, leucine, or asparagine but not proline. Similarity with the (glycine–alanine) repeats and poly(alanine) runs of arthropod silks also exists. Based on available evidence, a model of preCol axial assembly is proposed in which preCol-NG functions as a mediator between preCol-D/-P molecules. This is consistent with the observed progression of mechanical properties in byssal threads.
Apoptotic proteins Reaper and Grim induce stable inactivation in voltage-gated K
+
channels
Authors: Avdonin V. , Kasuya J. , Ciorba M. A. , Kaplan B. , Hoshi T. , Iverson L.
Published: July 2002

Drosophila
genes
reaper
,
grim
, and
head-involution-defective
(
hid
) induce apoptosis in several cellular
contexts. N-terminal sequences of these proteins are highly conserved
and are similar to N-terminal inactivation domains of voltage-gated
potassium (K
+
) channels. Synthetic Reaper and Grim N
terminus peptides induced fast inactivation of Shaker-type
K
+
channels when applied to the cytoplasmic side of the
channel that was qualitatively similar to the inactivation produced by
other K
+
channel inactivation particles. Mutations that
reduce the apoptotic activity of Reaper also reduced the
synthetic peptide’s ability to induce channel inactivation, indicating
that K
+
channel inactivation correlated with
apoptotic activity. Coexpression of Reaper RNA or direct
injection of full length Reaper protein caused near irreversible block
of the K
+
channels. These results suggest that Reaper and
Grim may participate in initiating apoptosis by stably blocking
K
+
channels.
A model for spontaneous B-lineage lymphomas inIgHμ-HOX11transgenic mice
Authors: Hough Margaret R. , Reis Marciano D. , Singaraja Roshni , Bryce Dawn Marie , Kamel-Reid Suzanne , Dardick Irving , Breitman Martin L. , Dubé Ian D.
Published: July 2002

HOX11, a divergent homeodomain-containing transcription factor, was isolated from the breakpoint of the nonrandom t(10;14)(q24;q11) chromosome translocation found in human T cell acute lymphoblastic leukemias. The translocation places theHOX11coding sequence under the transcriptional control ofTCRα/δ regulatory elements, resulting in ectopic expression of a normal HOX11 protein in thymocytes. To investigate the oncogenic potential of HOX11, we targeted its expression in lymphocytes of transgenic mice by placing the human cellular DNA under the transcriptional control of Ig heavy chain or LCK regulatory sequences. OnlyIgHμ-HOX11mice expressing low levels of HOX11 were viable. During their second year of life, allHOX11transgenic mice became terminally ill with more than 75% developing large cell lymphomas in the spleen, which frequently disseminated to thymus, lymph nodes, and other nonhematopoietic tissues. Lymphoma cells were predominantly clonal IgM+IgD+mature B cells. Repopulation of severe combined immunodeficient mice with cells from hyperplastic spleens indicated that theHOX11tumor phenotype was transplantable. Before tumor development, expression of the transgene did not result in perturbations in lymphopoiesis; however, lymphoid hyperplasia involving the splenic marginal zones was present in 20% of spleens. Our studies provide direct evidence that expression ofHOX11in lymphocytes leads to malignant transformation. These mice are a useful model system to study mechanisms involved in transformation from B-lineage hyperplasia to malignant lymphoma and for testing novel approaches to therapy. They represent a novel animal model for non-Hodgkin’s lymphoma of peripheral mature B cell origin.
Fetuin (α2-HS-glycoprotein) opsonizes cationic macrophagedeactivating molecules
Authors: Wang Haichao , Zhang Minghuang , Bianchi Marina , Sherry Barbara , Sama Andrew , Tracey Kevin J.
Published: July 2002

Macrophages become activated by bacterial endotoxin (lipopolysaccharide) and other stimuli to release proinflammatory cytokines and NO. To prevent release of toxic or potentially lethal quantities of these factors, the state of macrophage activation is counter-regulated by anti-inflammatory mediators (e.g., glucocorticoid hormones, interleukin 10, and transforming growth factor type β). Fetuin, a negative acute-phase protein, recently was implicated as an anti-inflammatory mediator, because it is required for macrophage deactivation by spermine. In the present studies, we found that fetuin is necessary for macrophages to respond to CNI-1493, a tetravalent guanylhydrazone inhibitor of p38 mitogen-activated protein kinase phosphorylation. Fetuin dose-dependently increases macrophage uptake of CNI-1493, which can be specifically inhibited by anti-human fetuin antibodies. Anti-human fetuin antibodies render primary human peripheral blood mononuclear cells insensitive to deactivation by CNI-1493. Thus, macrophages use fetuin as an opsonin for cationic-deactivating molecules, both endogenous (e.g., spermine) and pharmacologic (e.g., CNI-1493). This role of fetuin as an opsonic participant in macrophage-deactivating mechanisms has implications for understanding and manipulating the innate immune response.
Horseshoe crab acetyl group-recognizing lectins involved in innate immunity are structurally related to fibrinogen
Authors: Gokudan Soutaro , Muta Tatsushi , Tsuda Ryoko , Koori Kumiko , Kawahara Takeshi , Seki Noriaki , Mizunoe Yoshimitsu , Wai Sun N. , Iwanaga Sadaaki , Kawabata Shun-ichiro
Published: July 2002

We have characterized and cloned newly isolated lectins from hemolymph plasma of the horseshoe crab
Tachypleus tridentatus
, which we named tachylectins 5A and 5B (TLs-5). TLs-5 agglutinated all types of human erythrocytes and Gram-positive and Gram-negative bacteria. TLs-5 specifically recognize acetyl group-containing substances including noncarbohydrates; the acetyl group is required and is sufficient for recognition. TLs-5 enhanced the antimicrobial activity of a horseshoe crab-derived big defensin. cDNA sequences of TLs-5 indicated that they consist of a short N-terminal Cys-containing segment and a C-terminal fibrinogen-like domain with the highest sequence identity (51%) to that of mammalian ficolins. TLs-5, however, lack the collagenous domain found in a kind of “bouquet arrangement” of ficolins and collectins. Electron microscopy revealed that TLs-5 form two- to four-bladed propeller structures. The horseshoe crab is equipped with a unique functional homologue of vertebrate fibrinogen, coagulogen, as the target protein of the clotting cascade. Our observations clearly show that the horseshoe crab has fibrinogen-related molecules in hemolymph plasma and that they function as nonself-recognizing lectins. An ancestor of fibrinogen may have functioned as a nonself-recognizing protein.
Muscle degeneration without mechanical injury in sarcoglycan deficiency
Authors: Hack A. A. , Cordier L. , Shoturma D. I. , Lam M. Y. , Sweeney H. L. , McNally E. M.
Published: July 2002

In humans, mutations in the genes encoding components of the dystrophin–glycoprotein complex cause muscular dystrophy. Specifically, primary mutations in the genes encoding α-, β-, γ-, and δ-sarcoglycan have been identified in humans with limb-girdle muscular dystrophy. Mice lacking γ-sarcoglycan develop progressive muscular dystrophy similar to human muscular dystrophy. Without γ-sarcoglycan, β- and δ-sarcoglycan are unstable at the muscle membrane and α-sarcoglycan is severely reduced. The expression and localization of dystrophin, dystroglycan, and laminin-α2, a mechanical link between the actin cytoskeleton and the extracellular matrix, appears unaffected by the loss of sarcoglycan. We assessed the functional integrity of this mechanical link and found that isolated muscles lacking γ-sarcoglycan showed normal resistance to mechanical strain induced by eccentric muscle contraction. Sarcoglycan-deficient muscles also showed normal peak isometric and tetanic force generation. Furthermore, there was no evidence for contraction-induced injury in mice lacking γ-sarcoglycan that were subjected to an extended, rigorous exercise regimen. These data demonstrate that mechanical weakness and contraction-induced muscle injury are not required for muscle degeneration and the dystrophic process. Thus, a nonmechanical mechanism, perhaps involving some unknown signaling function, likely is responsible for muscular dystrophy where sarcoglycan is deficient.
Patterned library analysis: A method for the quantitative assessment of hypotheses concerning the determinants of protein structure
Authors: Lahr Steven J. , Broadwater Anne , Carter Charles W. , Collier Martha L. , Hensley Lucinda , Waldner Jennifer C. , Pielak Gary J. , Edgell Marshall Hall
Published: July 2002

Site-directed mutagenesis and combinatorial libraries are powerful tools for providing information about the relationship between protein sequence and structure. Here we report two extensions that expand the utility of combinatorial mutagenesis for the quantitative assessment of hypotheses about the determinants of protein structure. First, we show that resin-splitting technology, which allows the construction of arbitrarily complex libraries of degenerate oligonucleotides, can be used to construct more complex protein libraries for hypothesis testing than can be constructed from oligonucleotides limited to degenerate codons. Second, using eglin c as a model protein, we show that regression analysis of activity scores from library data can be used to assess the relative contributions to the specific activity of the amino acids that were varied in the library. The regression parameters derived from the analysis of a 455-member sample from a library wherein four solvent-exposed sites in an α-helix can contain any of nine different amino acids are highly correlated (P< 0.0001,R2= 0.97) to the relative helix propensities for those amino acids, as estimated by a variety of biophysical and computational techniques.
Loss of the circadian clock-associated protein 1 in
Arabidopsis
results in altered clock-regulated gene expression
Authors: Green R. M. , Tobin E. M.
Published: July 2002

Little is known about plant circadian oscillators, in spite of how important they are to sessile plants, which require accurate timekeepers that enable the plants to respond to their environment. Previously, we identified a circadian clock-associated (
CCA1
) gene that encodes an Myb-related protein that is associated with phytochrome control and circadian regulation in plants. To understand the role CCA1 plays in phytochrome and circadian regulation, we have isolated an
Arabidopsis
line with a T DNA insertion that results in the loss of
CCA1
RNA, of CCA1 protein, and of an
Lhcb
-promoter binding activity. This mutation affects the circadian expression of all four clock-controlled genes that we examined. The results show that, despite their similarity, CCA1 and LHY are only partially redundant. The lack of CCA1 also affects the phytochrome regulation of gene expression, suggesting that CCA1 has an additional role in a signal transduction pathway from light, possibly acting at the point of integration between phytochrome and the clock. Our results indicate that CCA1 is an important clock-associated protein involved in circadian regulation of gene expression.
(4-Aminomethyl)phenylguanidine derivatives as nonpeptidic highly selective inhibitors of human urokinase
Authors: Sperl Stefan , Jacob Uwe , Arroyo de Prada Nuria , Stürzebecher Jörg , Wilhelm Olaf G. , Bode Wolfram , Magdolen Viktor , Huber Robert , Moroder Luis
Published: July 2002

Increased expression of the serine protease urokinase-type plasminogen activator (uPA) in tumor tissues is highly correlated with tumor cell migration, invasion, proliferation, progression, and metastasis. Thus inhibition of uPA activity represents a promising target for antimetastatic therapy. So far, only the x-ray crystal structure of uPA inactivated by H-Glu-Gly-Arg-chloromethylketone has been reported, thus limited data are available for a rational structure-based design of uPA inhibitors. Taking into account the trypsin-like arginine specificity of uPA, (4-aminomethyl)phenylguanidine was selected as a potential P1 residue and iterative derivatization of its amino group with various hydrophobic residues, and structure–activity relationship-based optimization of the spacer in terms of hydrogen bond acceptor/donor properties led to
N
-(1-adamantyl)-
N′
-(4-guanidinobenzyl)urea as a highly selective nonpeptidic uPA inhibitor. The x-ray crystal structure of the uPA B-chain complexed with this inhibitor revealed a surprising binding mode consisting of the expected insertion of the phenylguanidine moiety into the S1 pocket, but with the adamantyl residue protruding toward the hydrophobic S1′ enzyme subsite, thus exposing the ureido group to hydrogen-bonding interactions. Although in this enzyme-bound state the inhibitor is crossing the active site, interactions with the catalytic residues Ser-195 and His-57 are not observed, but their side chains are spatially displaced for steric reasons. Compared with other trypsin-like serine proteases, the S2 and S3/S4 pockets of uPA are reduced in size because of the 99-insertion loop. Therefore, the peculiar binding mode of the new type of uPA inhibitors offers the possibility of exploiting optimized interactions at the S1′/S2′ subsites to further enhance selectivity and potency. Because crystals of the uPA/benzamidine complex allow inhibitor exchange by soaking procedures, the structure-based design of new generations of uPA inhibitors can rely on the assistance of x-ray analysis.
The Advanced Programmer's Reliance on Program Semantics: Evidence from some Cognitive Tasks
Authors: Wong Siu‐Yee , Cheung Him , Chen Hsuan‐Chih
Published: July 2002

This study examined the effects of programming expertise on the semantic processing of computer programs. Experiment 1 showed that sensitivity to semantic changes (i.e. changes of actual program functions) in a BASIC program recognition task increased with programming experience. No such pattern was observed for surface changes (i.e. changes of program syntax without functional alterations). The magnitude of semantic priming for BASIC keywords in a lexical decision task also increased with expertise, but the pattern was not found with normal English priming. In Experiment 2, novice BASIC programmers detected more semantic changes than the controls (non‐programmers) in BASIC programs; the reverse was found for surface changes. Both the controls and the novices detected more semantic than surface changes in English passages. The BASIC priming effect was found only with the novices whereas English priming was demonstrated with both the control and the novice participants. The present findings support the view that the programming expert relies particularly on semantic processing and such reliance is specific to programming activities. Practical implications of the present results are discussed.
Cognitive Enhancers: A View from Two Developing Countries
Authors: Izquierdo Ivan
Published: July 2002

Developing countries, such as Brazil or Argentina, share most of the benefits and problems concerning use of cognitive enhancers with developed countries; however, they present some peculiarities related to the potential clientele for these drugs. The ageing population has increased very sharply in Brazil and Argentina because of a rapid increase in life expectancy, but their financial means have not increased. Furthermore, the stress of poverty constitutes a major factor in the development of cognitive disturbances in these countries, in both the young and the old; these disturbances usually pertain to categories that should not be treated with cognitive enhancers.
The Dimensionality of Memory Strength Between Levels of Both Serial Position and Word Frequency Category
Authors: Duncan Matthew
Published: July 2002

In recognition tasks where Signal Detection Theory (SDT) is applied, a suitable decision variable is required. This variable is typically assumed to be a global assessment of memory strength. A further assumption is that factors such as old‐new, serial position (SP), and word frequency (WF) simply act to change the value of strength across levels within the factor. In terms of SDT, the decision variable is assumed to be uni‐dimensional. Four experiments are reported that provide a direct empirical assessment of this assumption for SP and WF. Judgements of items (JOI), recency (JOR), and primacy (JOP) were measured for SP; and subjective frequency (JOF) was measured for WF. Multiple dimensions imply non‐additive effects across factor levels and different retrieval processes or the influence of an extra process. A single dimension is consistent with an additive effect of factor levels and current theorizing. The data are in fairly good agreement with the uni‐dimensional assumption across all four factors with the exception of JOR and JOP. These showed less uni‐dimensionality for comparisons between beginning vs. end list items. The implications of this are discussed.
Déterminants de Satisfaction Conjugale Chez des Personnes Vivant une Première ou une Seconde Union Conjugale
Authors: Giguère Jeannine , Fortin Claudette , Sabourin Stéphane
Published: July 2002

Cette étude se propose de comparer la contribution de la motivation, de traits de personnalité et de variables sociodémographiques à la satisfaction conjugale de personnes vivant une première ou une seconde union conjugale. Un échantillon de 443 participants francophones, mariés ou en union de fait, dont 274 vivent une première union et 169, une seconde union conjugale, ont complété un ensemble de questionnaires. Les résultats d'analyses de régression multiple indiquent que chez les personnes des deux types d'union, l'amotivation serait un déterminant négatif de satisfaction conjugale alors que la motivation intrinsèque et la sociabilité agiraient comme prédicteurs positifs. D'autre part, la regulation introjectée et le névrotisme contribueraient négativement à l'ajustement conjugal uniquement chez les individus en seconde union tandis que l'ouverture et la propension à être consciencieux apporteraient une contribution positive seulement chez les gens en première union. Finalement, le fait d'avoir des enfants d'une première ou d'une seconde union contribuerait au bonheur conjugal des personnes en seconde union. Ce dernier résultat vient contredire ceux d'autres études signalant une relation entre une baisse de satisfaction conjugale de personnes remariées et la présence d'enfants d'une union antérieure.
New Zealand's national drug policy
Authors: WEBB M. B.
Published: July 2002

The paper describes the origins, development and key features of New Zealand's national drug policy (NDP). This 5‐year policy, launched in July 1998, aims of minimize the harm caused by drug use to both individuals and the community. Major achievements since the release of the NDP are reviewed, focusing on the establishment of a two‐tier monitoring and implementation structure and release of the policy's first intersectoral work programme. [Webb H. B. New Zealand's national drug policy. Drug Alcohol Rev 1999; 18:435–440]
Encouraging general practitioners to take up screening and early intervention for problem use of alcohol: a marketing trial
Authors: McCORMICK ROSS , ADAMS PETER , POWELL ANNE , BUNBURY DEAN , PATON‐SIMPSON GRANT , McAVOY BRIAN
Published: July 2002

The aim of this study was to explore the result and cost of marketing techniques designed to encourage general practitioners to receive an early intervention and screening package for problem use of alcohol. A randomized controlled trial of marketing to 369 New Zealand general practitioners is described. The marketing techniques compared were direct mail, telemarketing and personal marketing. Each marketing strategy had a common promotional content. The screening and early intervention procedure marketed in each strategy was the ‘Drinkless’ package developed with the World Health Organization collaborative study for early intervention for at risk alcohol consumption. The package uses the Alcohol Use Disorders Identification Test (AUDIT). The major outcome was Drinkless package uptake defined as agreement to receive the package. The cost of each marketing technique was estimated. General practitioners approached using telemarketing or personal marketing are over 23% more likely to take up the package than those approached by mail. There was no significant difference between the uptake rates for telemarketing (74%) and personal marketing (81%). Estimating the marginal cost per doctor agreeing to receive the Drinkless package showed telemarketing to cost approximately $3.97 per doctor compared to $10.00 for direct mail and $20.36 for personal marketing. Telemarketing is the most cost‐effective marketing strategy to encourage general practitioners to receive a screening and early intervention package for problem use of alcohol.
Reply to Kurz and Salvadori
Authors: Peach Terry
Published: July 2002

Professors Kurz and Salvadori seem aggrieved by my review article of their Companion (Peach 1999; Kurz and Salvadori 1998). They give the impression that the article should never have been published, apparently on the grounds that I had “disqualified” myself from writing it: I was not an “unprejudiced reviewer.” At the same time, they pronounce that the article “has not much to offer,” which makes it all the more curious that they should trouble themselves to discredit its author.
How Quesnay's Tableau Économique Offered a Deeper Analysis of the Predicament of France
Authors: Eltis Walter
Published: July 2002

When François Quesnay began to publish on economics there were unmistakable indications that fundamental change was required in France. The finances of the State were in perpetual difficulty, and it had to borrow at higher interest rates than the private sector. Paris was the intellectual capital of Europe, and France was unquestionably one of Europe's great powers, but she had difficulty in simultaneously financing the Army and the Navy, which her international ambitions required. In the repeated wars with Great Britain in what has been described as the Second Hundred Years War (dating from 1688 until 1815) military weaknesses under the Bourbons associated with inadequacies of finance hampered France's efforts to match Britain in the colonization and exploitation of the wealth of North America and India. In the absence of representative institutions such as the British Parliament, the wealthy in France would not consent to the taxation required to establish the French State on a financial foundation commensurate with its political aspirations.
Ethanol alters the inhibitory effect of calcium ions on [3H]‐inositol 1,4,5‐trisphosphate binding
Authors: RODRÍGUEZ F. DAVID
Published: July 2002

In this study we have analysed the effects of ethanol and divalent cations on the binding of [3H]‐inositol 1,4,5 trisphosphate to rat cerebellar membranes. Rats were injected intraperitoneally, daily, with 3g of ethanol/kg of body weight for different periods of time. Repeated in vivo administration of ethanol caused a reduction of about 30% of binding in an in vitro assay carried out in the presence of 1 mM EDTA. With an IC approximately 250 nM calcium ions produced a reduction in binding to cerebellar membranes isolated from control rats. The inhibitory effect was not observed in membranes taken from animals injected with alcohol for 21 days. Magnesium and manganese ions also lowered IP binding. The metabolic degradation of IP to IP was increased by magnesium and manganese but not by calcium and was similar in control and ethanol 2 treated rats. The results indicate that ethanol repeatedly administered to rats modifies the sensitivity of the IP receptor to calcium ion, but that it does not alter the metabolic fate of IP to IP. This supports the idea that ethanol may have preferable targets within the cell.
NMDA‐receptor antagonists block the development of rapid tolerance to ethanol in mice
Authors: BARRETO PATRÍCIA SOBIERAJSKI , LEMOS TADEU , MORATO GINA STRUFFALDI
Published: July 2002

Several studies have emphasized the role of learning in the development of rapid and chronic tolerances. Recently, it was shown that the NMDA antagonists MK‐801(dizocilpine) and ketamine block the development of tolerance to ethanol in rats submitted to tilt‐plane apparatus. The present study examines the generality of this inhibition using mice submitted to the rota‐rod test. Mice were tested in the rota‐rod apparatus at 5, 10 and 15 minutes after intraperitoneal ethanol injections. The first experiment evaluated the time course of acute effects of different doses of ethanol (1.0‐2.25 g/kg) in the rota‐rod test. In the second experiment, the most effective dose of ethanol to produce rapid tolerance (RT) was determined. Mice were injected on day 1 with ethanol or saline and tested on the rota‐rod. After 24 hours, all groups were injected with the same doses of ethanol and tested. The third experiment investigated whether ketamine (1.0‐5.0 mg/kg) injected before ethanol on day 1 influenced the development of RT to ethanol. The last experiment compared the actions of the (+) and (‐)MK‐801 isomers (0.015‐0.060 mg/kg) on RT to ethanol. Maximum motor impairment was obtained 5 minutes after ethanol injections. Pretreatment of animals with ketamine (2.5 and 5 mg/kg) or with (+)MK‐801 (0.030 and 0.060 mg/kg) significantly blocked the development of RT. The (‐)MK‐801 isomer did not affect RT, suggesting that the blockade by MK‐801 is stereospecific. These results confirm and extend previous studies showing that NMDA receptor antagonists block RT to the motor impairment produced by ethanol in other animals tested in different models.
Alcohol‐thiamine interactions: an update on the pathogenesis of Wernicke encephalopathy
Authors: TODD KATHRYN G. , HAZELL ALAN S. , BUTTERWORTH ROGER F.
Published: July 2002

Wernicke encephalopathy is a neurological disorder commonly observed in chronic alcohol abuse, in patients with AIDS, and in other conditions of compromised nutritional status. The underlying cause of the disorder is thiamine deficiency. The present review highlights data focusing on alcohol‐thiamine interactions and their relationship to the pathogenesis of Wernicke encephalopathy. Recent findings on the effects of alcohol on thiamine absorption and storage and on thiamine phosphorylation to the enzyme co‐factor form (thiamine diphosphate) are discussed with regard to the postulated “biochemical lesion” of Wernicke encephalopathy. Also discussed are new findings on the molecular genetics of the thiamine‐dependent enzyme transketolase in patients with Wernicke encephalopathy. A discussion of the hypotheses regarding the mechanisms underlying the phenomenon of selective neuronal cell death observed in this disorder including cerebral energy deficit, focal lactic acidosis, glutamate excitotoxicity, increased expression of immediate‐early genes, free radicals and perturbations of the blood‐brain barrier are presented. Finally, the possible role of thiamine deficiency in alcoholic peripheral neuropathy is reviewed.
The FAS Screen: a rapid screening tool for fetal alcohol syndrome
Authors: BURD LARRY , COX CHAUN , POITRA BETTY , WENTZ TOM , EBERTOWSKI MARY , MARTSOLF JOHN T. , KERBESHIAN JACOB , KLUG MARILYN G.
Published: July 2002

Fetal alcohol syndrome (FAS) is an important cause of mental retardation and developmental disabilities. A population based screening tool would allow for early diagnosis and entry into intervention programs. The aim of the study was to develop a brief screening tool for use in population‐based settings to improve the identification of children with FAS. The FAS Screen was developed and tested in six sites. These were sites that served children and all were located in North Dakota. Screening was completed on 1013 children, 65 were found to have a positive screening score and were referred for further investigation. Forty were seen for evaluation by a medical geneticist and six were diagnosed with FAS. The estimated values for the screening tool were: specificity 94.1%, sensitivity 100%, positive predictive value 9.1% and negative predictive value 100%. The cost of screening was $13.00 per child and the cost per case identified was $4,100. The FAS Screen is a brief screening test with acceptable performance characteristics and is cost effective.
The DRD2 A1 allele: a behavioural genetic risk factor in hepatitis C infection of persistent drug abusers
Authors: LAWFORD BRUCE , YOUNG ROSS , NOBLE ERNEST P. , CRAWFORD DARRELL , ROWELL JOHN , SHADFORTH SUSAN , RITCHIE TERRY , ZHANG XUXIAN , COOKSLEY GRAHAM E.
Published: July 2002

Hepatitis C is highly prevalent among intravenous drug abusers, but to date research has not widely explicated behavioural risk factors regarding acquisition of infection. The A allele of the D dopamine receptor (DRD2) gene is a hypothesized risk factor in the development of severe drug dependence and alcoholism. The present study compares the frequency of the A1 allele of the DRD2 gene among 37 patients presenting to a hepatitis clinic for treatment of hepatitis C, 23 hepatitis C‐negative drug‐abusing patients maintained on methadone and 33 non‐drug‐abusing controls. The results indicated that hepatitis C‐positive patients were significantly more likely to display the A1 allele than hepatitis C‐negative patients, who were in turn more likely to have the A1 allele than controls. Furthermore, the hepatitis C subjects manifested more persistent drug‐seeking behaviour than the other drug‐abusing group. The implications of this finding in terms of drug‐related reward are discussed. Future research should attempt to evaluate host risk factors, in order to enable more precisely targeted attempts at harm minimization.
A comparison of five commercial immunoassays for the detection of flunitrazepam and other benzodiazepines in urine
Authors: BARRETT A. M. , WALSHE K. , KAVANAGH P. V. , McNAMARA S. M. , MORAN C. , BURDETT J. , SHATTOCK A. G.
Published: July 2002

Five commercially available immunoassay test kits (SYVA EMIT® d.a.uTM, SYVA EMIT® II assay, Abbott FPIA, Cozart Auto‐Lyte® and Roche Abuscreen® OnlineTM, all used for the benzodiazepine group of drugs) were evaluated for their ability to detect flunitrazepam, its major urinary metabolite, 7‐aminoflunitrazepam, and several other benzodiazepines at serial dilutions (final concentration 25–1000 ng/ml) in drug‐free urine and in urines following oral administration of flunitrazepam (1–3 mg). For comparison, gas chromatography/mass spectrometry was used to measure urinary levels of 7‐aminoflunitrazepam. Levels of drug detected in the study were compared with the cross‐reactivities presented by the manufacturers for each individual kit. One to three mg doses of flunitrazepam were taken by volunteers and levels excreted in urine analysed over several hours. A positive response was obtained in several samples from volunteers who had taken 2 mg or 3 mg doses, but not a 1 mg dose. Thirty‐five clinical samples from the individuals suspected of benzodiazepine abuse were also examined. The results were not consistent among the kits evaluated.We conclude that the test kits evaluated in this study do not detect flunitrazepam reliably, due primarily to their poor sensitivities.
Orientation of Membrane‐Bound Melittin Studied by a Combination of HPLC and Liquid Secondary Ion Mass Spectrometry (LSIMS)
Authors: Niu Wei , Wu Yi , Sui Sen‐Fang
Published: July 2002

Combining two analytical techniques, HPLC and liquid secondary ion mass spectrometry, the orientation of liposomal membrane‐bound melittin was analyzed through its trypsindigested products. We found that trypsin can access all proteolytic sites of the membrane‐bound melittin when the liposomes have no transmembrane potential, whereas the proteolytic site near the N terminus of melittin is blocked when the liposomes have a negative transmembrane potential. The results suggest that the negative transmembrane potential may induce the melittin molecules to insert into the membrane perpendicularly, whereas melittin lies flat on the membrane surface in the absence of a negative potential.
GalNAc-α-O-benzyl Inhibits NeuAcα2-3 Glycosylation and Blocks the Intracellular Transport of Apical Glycoproteins and Mucus in Differentiated HT-29 Cells
Authors: Huet Guillemette , Hennebicq-Reig Sylviane , de Bolos Carmen , Ulloa Fausto , Lesuffleur Thécla , Barbat Alain , Carrière Véronique , Kim Isabelle , Real Francisco X. , Delannoy Philippe , Zweibaum Alain
Published: July 2002

Exposure for 24 h of mucus-secreting HT-29 cells to the sugar analogue GalNAc-α-O-benzyl results in inhibition of Galβ1-3GalNAc:α2,3-sialyltransferase, reduced mucin sialylation, and inhibition of their secretion (Huet, G., I. Kim, C. de Bolos, J.M. Loguidice, O. Moreau, B. Hémon, C. Richet, P. Delannoy, F.X. Real., and P. Degand. 1995. J. Cell Sci. 108:1275–1285). To determine the effects of prolonged inhibition of sialylation, differentiated HT-29 populations were grown under permanent exposure to GalNAc-α-O-benzyl. This results in not only inhibition of mucus secretion, but also in a dramatic swelling of the cells and the accumulation in intracytoplasmic vesicles of brush border–associated glycoproteins like dipeptidylpeptidase-IV, the mucin-like glycoprotein MUC1, and carcinoembryonic antigen which are no longer expressed at the apical membrane. The block occurs beyond the cis-Golgi as substantiated by endoglycosidase treatment and biosynthesis analysis. In contrast, the polarized expression of the basolateral glycoprotein GP 120 is not modified. Underlying these effects we found that (a) like in mucins, NeuAcα2-3Gal-R is expressed in the terminal position of the oligosaccharide species associated with the apical, but not the basolateral glycoproteins of the cells, and (b) treatment with GalNAc-α-O-benzyl results in an impairment of their sialylation. These effects are reversible upon removal of the drug. It is suggested that α2-3 sialylation is involved in apical targeting of brush border membrane glycoproteins and mucus secretion in HT-29 cells.
Negative Regulation of FcεRI-mediated Degranulation by CD81
Authors: Fleming Tony J. , Donnadieu Emmanuel , Song Chang Ho , Laethem Francois Van , Galli Stephen J. , Kinet Jean-Pierre
Published: July 2002

Signaling through the high affinity receptor for immunoglobulin E (FcεRI) results in the coordinate activation of tyrosine kinases before calcium mobilization. Receptors capable of interfering with the signaling of antigen receptors, such as FcεRI, recruit tyrosine and inositol phosphatases that results in diminished calcium mobilization. Here, we show that antibodies recognizing CD81 inhibit FcεRI-mediated mast cell degranulation but, surprisingly, without affecting aggregation-dependent tyrosine phosphorylation, calcium mobilization, or leukotriene synthesis. Furthermore, CD81 antibodies also inhibit mast cell degranulation in vivo as measured by reduced passive cutaneous anaphylaxis responses. These results reveal an unsuspected calcium-independent pathway of antigen receptor regulation, which is accessible to engagement by membrane proteins and on which novel therapeutic approaches to allergic diseases could be based.
The Effect of Graft-versus-Host Disease on T Cell Production and Homeostasis
Authors: Dulude Gaël , Roy Denis-Claude , Perreault Claude
Published: July 2002

The aim of this work was to decipher how graft-versus-host disease (GVHD) affects T cell production and homeostasis. In GVHD+ mice, thymic output was decreased fourfold relative to normal mice, but was sufficient to maintain a T cell repertoire with normal diversity in terms of Vβ usage. Lymphoid hypoplasia in GVHD+ mice was caused mainly by a lessened expansion of the peripheral postthymic T cell compartment. In 5-bromo-2′-deoxyuridine pulse-chase experiments, resident T cells in the spleen of GVHD+ mice showed a normal turnover rate (proliferation and half-life). When transferred into thymectomized GVHD− secondary hosts, T cells from GVHD+ mice expanded normally. In contrast, normal T cells failed to expand when injected into GVHD+ mice. Thus, the reduced size of the postthymic compartment in GVHD+ mice was not due to an intrinsic lymphocyte defect, but to an extrinsic microenvironment abnormality. We suggest that this extrinsic anomaly is consistent with a reduced number of functional peripheral T cell niches. Therefore, our results show that GVHD-associated T cell hypoplasia is largely caused by a perturbed homeostasis of the peripheral compartment. Furthermore, they suggest that damage to the microenvironment of secondary lymphoid organs may represent an heretofore unrecognized cause of acquired T cell hypoplasia.