bluuebunny/crossref_metadata_2025 huggingface dataset:
The Acculturation Scale for Vietnamese Adolescents (ASVA): A bidimensional perspective
Authors: Nguyen Huong H. , Von Eye Alexander
Published: July 2002

The purpose of this study was to develop an acculturation scale that: (1) empirically demonstrated the bidimensional model; and (2) that pertained to the concerns of Vietnamese adolescents. Altogether, 191 Vietnamese students (ages 10–23) were recruited from eight middle schools and high schools in Lansing, Michigan (USA). Based on responses from their questionnaires, results indicated that The Acculturation Scale for Vietnamese Adolescents (ASVA) demonstrated good reliability and validity overall. Confirmatory factor analyses also demonstrated support for the ASVA's two dimensions (Involvement in the Vietnamese Culture and Involvement in the US Culture) and four life-domains within each dimension (i.e., Group Interactions, Everyday Lifestyles, Family Orientation, and Global Involvements). The CFAs indicated that the ASVA's two-factor and four-factor structures achieved an excellent fit to the data and furthermore, that a bidimensional, two-factor model was superior to a unidimensional, bipolar one predominantly used in acculturation scales today. As such, this study demonstrated the utility of viewing acculturation from a two-dimensional framework; it also provided researchers a practical, 2D scale to use.
Adult attachment styles and emotional biases
Authors: Magai Carol , Hunziker Jill , Mesias Wilda , Culver L. Clayton
Published: July 2002

This study was designed to extend the literature on personality differences and emotion biases among individuals characterised by different attachment patterns. Sixty-three individuals ( M = 63 years) completed measures of parental child-rearing practices and trait emotion; they also completed a storytelling task and an emotion decoding task and were videotaped during an emotion induction procedure for later facial coding. Attachment patterns were assessed using a semi-structured interview and a four-category coding system. Multiple regression was applied to the data to test attachment models.

Analyses based on theoretical models accounted for 23–47% of the variance in attachment patterns. Alternative, empirical models, developed on the basis of observed bivariate associations, resulted in the improvement of three models. Attachment security was associated with facial expressions of joy, the absence of love-withdrawal as a parental disciplinary style, a decoding bias favouring shame, a disinclination to route negative affect from consciousness, and low scores on negative trait emotion. Fearful avoidance was typified by facial shame, punitive parental child-rearing practices, the inclination to see anger in faces, to tell stories with approval-seeking themes, and with trait anxiety. Dismissingness was characterised by mixed or ambivalent facial activity, the tendency to see disgust in faces, and to deny anxiety and yet write projective stories revealing inner conflict. Preoccupation was predicted by parental love-withdrawal, facial disgust, fantasies of closeness and affiliation, and trait anger and depression. Findings are discussed within the context of attachment theory and contemporary concepts concerning emotional organisation.
Noncompliance and child-rearing attitudes as predictors of aggressive behaviour: A longitudinal study in Chinese children
Authors: Chen Xinyin , Chen Huichang , Wang Li , Liu Mowei
Published: July 2002

The purpose of the study was to examine contributions of early personal and socialisation factors to the prediction of aggressive behaviour in Chinese children. A sample of children, initially at 2 years of age, and their parents in the People's Republic of China participated in this two-year longitudinal study. Observational data were collected on children's noncompliance in mother-child interactions at Time 1 and aggressive behaviour in peer interactions at Time 2. In addition, information concerning child-rearing attitudes were obtained from parental reports. The results indicated that boys had higher scores than girls on physical and verbal aggression at 4 years of age. Early noncompliance significantly and positively predicted aggressive behaviour. Parental child-rearing attitudes had unique, but generally weak, contributions to the prediction of aggression. Finally, the relations between child-rearing variables and child aggression might be different for boys and girls.
Social support satisfaction of Australian children
Authors: Shute Rosalyn , De Blasio Tony , Williamson Paul
Published: July 2002

This is the first in-depth study of the social support satisfaction of Australian children, measured using the “My Family and Friends” interview (Reid, Landesman, Treder, & Jaccard, 1989). This, together with the Self-Perception Profile for Children (Harter, 1985), was administered to 70 Adelaide children aged 9–11. A main effect of support provider and an interaction between support type and provider were found. Self-esteem was predicted by both overall social support satisfaction and network size. The Australian children reported lower levels and different patterns of support in comparison with previously published data from the USA. Australian parents were perceived as less “generalist” in their support, giving particularly low levels of companionship support. Friends gave high levels of companionship support but low levels of all other types; this, as in the case of parents, makes Australian friends more “specialist” supporters than their US counterparts.
Oral language and reading abilities of first-grade Peruvian children: Associations with child and family factors
Authors: Castro Dina C. , Lubker Bobbie B. , Bryant Donna M. , Skinner Martie
Published: July 2002

This study investigated the relationship between selected child and family demographic characteristics (child age, child sex, child birth order, maternal education, and parent language status), family processes (parent-to-child reading at home, and parent expectations about child’s educational attainment), and preschool experience with poor Peruvian first-grade children’s oral language and reading abilities, and examined whether those factors help to explain differences among children living in poverty. First-grade students ( N = 137) of five schools in a poor neighbourhood of Lima, Peru participated in the study. Children were given picture vocabulary, verbal analogies, letter-word identification, and reading comprehension tests. Information about the children and their families was gathered through parent interviews. Children whose parents had higher expectations obtained higher scores on picture vocabulary, verbal analogies, letter-word identification and reading comprehension. Children who attended private and public preschools obtained higher scores in letter-word identification than those who did not attend preschool. These findings support previous research on the relevance of family beliefs, above and beyond sociodemographic variables, as contributors to children’s oral language and reading, and provide some evidence of the benefits of preschool among children living in poverty. Future research is recommended to identify the specific strategies used by low-income Peruvian parents with high expectations to support their children’s language and reading; and to determine the relationships between type and quality in Peruvian preschool programmes, and programme practices that may differentially affect children’s language and reading skills.
Item Response Models for Assessing Change in Dichotomous Items
Authors: Spiel Christiane , Gluck Judith
Published: July 2002

The paper discusses three methodological approaches to measuring change in developmental research using item response models. To illustrate application, an empirical example using data from the Vienna Developmental Study is presented: 94 kindergarten students were presented twice with a set of k dichotomous item s measuring general developmental status. First, we analysed individual changes using a residual-analytic approach based on measures from the dichotomous Rasch Model. Second, in a confirmatory approach, we investigated group-specific changes in a quasi-experimental design using the Hybrid Linear Logistic Model with Relaxed Assumptions. Third, we presented an exploratory method to search for subgroups of subjects that differ systematically in developmental patterns using Mixed Rasch Models. The discussion focuses on the virtues and limitations of the three approaches.
Discourse Asymmetries in Adolescent Daughters’ Disputes with Mothers
Authors: Hofer Manfred , Sassenberg Kai , Pikowsky Birgit
Published: July 2002

Audiotaped disputes of 101 mother-daughter dyads (daughter ages 11-20) were used to examine discourse asymmetry in parent-child relationships. To grasp the exchange of arguments, an observation instrument was designed. Parallel surveys assessed the extent to which mothers felt they tried to control daughters’ behaviour and the extent to which daughters felt they tried to separate from and maintain connection with their mothers in their main argument. Findings suggest that mothers and daughters displayed dominant behaviour in different parts of the disputes. Although mothers dominated in the regulative aspects of discourse, daughters took the lead in the argumentative parts. They dominated in questioning mothers’ arguments and adding counterarguments. Sequential analyses showed that daughters were more likely to follow mothers’ initiatives and contradict their arguments than vice versa. Subjective understanding of the discourse was related to specific interactions. Mothers’ and daughters’ verbal behaviour displayed a curvilinear age-dependent pattern. Subjective data, however, showed no age differences.
Intra-individual Change and Inter-individual Differences in Negative Mood States of Older Women
Authors: Quinn Mary Ellen , Martin Peter
Published: July 2002

The primary purpose of this exploratory study was to examine the stability and lability of negative mood from a health perspective. Negative mood factor structure was examined in order to evaluate intra-individual change. Few studies have addressed factorial invariance across individuals and across time. The sample was comprised of four women in their 60s and four women in their 80s. Short-term intra-individual change and inter-individual differences in negative mood were assessed with a replicated single-subject design. Participants completed items from the 8SQ questionnaire for 100 consecutive days. P-technique factor analysis was used to examine the structure of negative mood factors, which were than graphed to determine level change over time. The number of factors were consistent, however, the items comprising the factors were not consistent across all participants. Patterns of intra-individual change in the negative mood factor of “ fatigue” was found to be highly individualised.
Social Competence, Maternal Attentiveness, and Overprotectiveness: Only Children in Korea
Authors: Doh Hyun-Sim , Falbo Toni
Published: July 2002

A study was conducted in South Korea that compared the social competence of sixth graders who had no siblings to those who did. Korea was selected as the site of this study because most urban mothers are homemakers there. The three factors of social competence considered in this study were: popularity, sociability, and brattiness. These three were measured in terms of the combined ratings of mothers and teachers. Maternal attentiveness and overprotectiveness was measured in terms of the mothers rating their own behaviour. Only children were found to score similarly to others on popularity and sociability, but scored worse than others on the brattiness scale. Maternal attentiveness was found to be correlated significantly with all three social competence scores, indicating that mothers who evaluated themselves as more attentive to their children had children who were evaluated as being more popular, sociable, and less bratty. However, mothers of only children were not found to score differently than other mothers on attentiveness or overprotectiveness. The findings about only children were interpreted in terms of Korean perspectives on play.
The Land Reform Policy Group in Scotland
Authors: Lloyd M. G. , Danson M. W.
Published: July 2002

In Scotland, the land question comprises issues associated with the legal context, ownership, use an d management of the resource. The con text within which the land question has been addressed has changed quite dramatically over the past decade, as a consequence of the Scottish Parliament an d the policy impetus associated with sustainable development. These have combined to focus attention on the relationship between economic change an d environmental quality an d on the appropriateness of management regimes to secure a feasible balance of interests. In 1997, the (then) Scottish Office established a Land Reform Policy Group to identify an d assess proposals for land reform in rural Scotland. Its main aim was to provide the Scottish Parliament with an agenda for action on land reform. The Land Reform Policy Group has stated that land reform legislation should set out clearly the objectives of land use and land reform; the basis for public sector involvement in land matters; and bring together a comprehensive range of measures for removing barriers and promoting positive action . This paper examines the emergence of the Policy Group as an institution al sponsor in effecting an agenda for land reform in Scotland.
The Critical Role of House Dust in Understanding the Hazards Posed by Contaminated Soils
Authors: Paustenbach Dennis J. , Finley Brent L. , Long Thomas F.
Published: July 2002

The health risks posed by soil pollutants are generally thought to be due to soilingestion and have often resulted in massive regulatory efforts to remedy such contamination. The contribution of this route to the actual human health hazard has been questioned, however, as soil removal alone seems to have little influence on the body burdens of soil contaminants in exposed individuals. Ongoing research also has repeatedly and substantially reduced the estimates of soilingested daily. Because comparatively little time is spent outdoors by most individuals, exposure to soil brought indoors, present as house dust, is now thought to be nearly as important as the directingestion of soil. Exposure via house dust has not been studied specifically, but several observations suggest that it may be important. Dust is largely composed of fine particles of tracked-in soil. The smaller dust particles cling to surfaces better than soil, and contaminant concentrations are often higher in house dust. Fine particles are likely to be more bioavailable, and degradation is slower indoors. Contaminants thus may be concentrated and more readily available in the areas most frequented. In some studies, contaminant levels in dust are correlated more closely with body burdens of contaminants than other sources, suggesting that this route should be considered when assessing risks from soil. Until more research addressing exposure to dust is conducted, recommendations for assessing potential health risks from this pathway are provided.
Identifying Hazards and Risks of Soil Contamination
Authors: Greim Helmut
Published: July 2002

The effects of contaminated soils on human health have rarely been observed, although models usually predict high exposure from contaminated soil. Such overestimation mostly results from insufficient data on the bioavailability of the chemical, which largely depends on the mobility of the compound in soil and the absorption rate via direct uptake by humans or indirectly via the food chain. It is therefore questionable to regulate soil contamination on the basis of toxicologically derived control levels because the transfer rates from soil to humans are not predictable unless very specific information on the different parameters affecting this transfer are available. Instead, soil control levels should be derived from ecotoxicological considerations or a specific evaluation of the contaminated area should be performed if contamination significantly exceeds the average. Setting soil control levels by considering effects on ecosystems including plants and possibly animals is presently being discussed by the Beratergremium für umweltrelevante Altstoffe and has been proposed previously.
Comparative Efficacy of three Methemoglobin Formers in Delaying Effects of Infused Sodium Cyanide
Authors: Menton R. G. , Reid F. M. , Olson C. T. , Niemuth N. A. , Audet K. K. , Marino M. , Brewer T. G. , Korte D. W.
Published: July 2002

A prophylactic treatment is needed to circumvent constraints of the current therapy for cyanide (CN-) intoxication: intravenous administration of sodium nitrite and sodium thiosulfate. Experiments were conducted to compare the anticyanide effects of three candidate pretreatment methemoglobin (MHb)-forming compounds in an anesthetized animal model. The experiment was conducted in 5 periods, with each of 9 animals receiving the vehicle control in period 1, 0.2 mg/kg p-aminopropiophenone (PA PP) in period 2, and 2.5 mg/kg WR242511 in period 3. Four of the animals received the vehicle control in period 4 followed by 7 mg/kg p-aminoheptanophenone (PA HP) in period 5, and 5 animals received 7 mg/kg PA HP in period 4 followed by the vehicle control in period 5. Sodium cyanide (Na CN) infusions for PAPP, PAHP, and WR242511 experiments were initiated when the predicted MHb level was approximately 5%. Infusions were stopped 10 s after no functional breaths (respiratory arrest) were observed. Blood samples were collected for hemoglobin (Hb), MHb, and total blood CN levels at scheduled time points. Time to respiratory arrest, percent MHb, and Na CN dose were the primary response parameters. A 11 pretreatment regimens effectively mitigated the effects of Na CN poisoning compared to the vehicle control (p <.05). No discernable differences in protection were provided by the three compounds. The results indicated that the protective effect is related to the MHb level rather than the specific pretreatment drug.
Quality of Life Implications as a Consequence of Surgery: Limb Salvage, Primary and Secondary Amputation
Authors: Eiser Christine , Darlington Anne-Sophie E. , Stride Chris B. , Grimer Robert
Published: July 2002

Purpose. We investigated self‐reported quality of life (QoL), body image and daily competence of patients as a consequence of
limb salvage surgery (LSS), primary or secondary amputation, and the views of patients following secondary amputation.

Patients. Patients (n=37) had all been treated for osteosarcoma or Ewing′s sarcoma in the lower limb.

Methods. QoL was measured by questionnaire. A separate interview to determine satisfaction with decision‐making was
conducted with those treated for secondary amputation.

Results. For the total group, QoL was below that expected from population norms. There were no differences in QoL between
those undergoing LSS surgery compared with amputation. However, LSS reported better daily competence and were less likely
to use a walking aid. For the total group, body image and daily competence were associated with better QoL.

Discussion. All these patients are at risk of compromised QoL following surgery. Our data are in line with previous work
suggesting outcomes may be better for LSS compared with amputation. Following secondary amputation, most patients (80%)
did not regret initial LSS treatment, but felt that the time gained allowed them to come to terms with subsequent surgery.
A Comparison Of Three Therapy Methods For Children With Different Types Of Developmental Phonological Disorder
Authors: Dodd Barbara , Bradford Amanda
Published: July 2002

Treatment case studies of three children whose speech was characterized by non‐developmental errors are described. Three therapy methods were trialed with each child: phonological contrast; core vocabulary and PROMPT. The accuracy and intelligibility of the childrenA's connected speech improved throughout the course of the programme. Intervention that focused on teaching a rule about the contrastive use of phonemes was most successful for a child who consistently made non‐developmental errors. Children making inconsistent errors received most benefit from the core vocabulary approach that markedly enhanced consistency of production. However, once consistency was established, one child benefited from phonological contrast therapy. While the results of the study should be interpreted with caution due to the small sample size and the cumulative effects of intervention, the findings suggest that different parts of a childA's phonological and phonetic system may respond to various types of treatment approaches that target different aspects of speech production. The implication drawn is that just as no single treatment approach is appropriate for all children with disordered phonology, management of some children may involve selecting and sequencing a range of different approaches.
Metaphonological skills of children with phonological disorders before and after phonological and metaphonological intervention
Authors: Major Eva M. , Bernhardt Barbara Handford
Published: July 2002

This study investigated the relationships between the phonological and metaphonological skills of 19 children aged 3‐5 years with moderate to severe phonological disorders, and the effects of intervention on the children's awareness skills. Seven tasks were used which required children to produce alliterations and rhymes, to segment sentences, disyllabic and monosyllabic words, and to change the names of objects. Children's metaphonological skills were tested (a) before intervention, (b) following phonological intervention and (c) following phonological plus metaphonological intervention. Evaluation of children's segmental and syllable/wordshape profiles before intervention indicated that children with larger phonetic inventories and better word and syllable shapes tended to have higher metaphonology task scores. Individual variation, however, suggested that children's overall phonological profiles rather than particular characteristics of their speech were more important for good metaphonological task performance. Children's phonological awareness skills were also related to their morphosyntactic production skills. Intervention outcomes indicated that both phonological and metaphonological intervention may result in a significant increase in children's metaphonological task performance. It was further observed that children with more moderate phonological disorders and good morphosyntactic production skills tended to improve on the metaphonological tasks after phonological intervention alone. Children with more severe phonological and morphosyntactic disorders tended to increase their task performance only after phonological plus metaphonological intervention.
Differential Regulation and Function of CD73, a Glycosyl-Phosphatidylinositol–linked 70-kD Adhesion Molecule, on Lymphocytes and Endothelial Cells
Authors: Airas Laura , Niemelä Jussi , Salmi Marko , Puurunen Tarja , Smith David J. , Jalkanen Sirpa
Published: July 2002

CD73, otherwise known as ecto-5′-nucleotidase, is a glycosyl-phosphatidylinositol–linked 70-kD molecule expressed on different cell types, including vascular endothelial cells (EC) and certain subtypes of lymphocytes. There is strong evidence for lymphocyte CD73 having a role in several immunological phenomena such as lymphocyte activation, proliferation, and adhesion to endothelium, but the physiological role of CD73 in other cell types is less clear. To compare the biological characteristics of CD73 in different cell types, we have studied the structure, function, and surface modulation of CD73 on lymphocytes and EC. CD73 molecules on lymphocytes are shed from the cell surface as a consequence of triggering with an antiCD73 mAb, mimicking ligand binding. In contrast, triggering of endothelial CD73 does not have any effect on its expression. Lymphocyte CD73 is susceptible to phosphatidylinositol phospholipase, whereas only a small portion of CD73 on EC could be removed by this enzyme. Furthermore, CD73 on EC was unable to deliver a tyrosine phosphorylation inducing signal upon mAb triggering, whereas triggering of lymphocyte CD73 can induce tyrosine phosphorylation. Despite the functional differences, CD73 molecules on lymphocytes and EC were practically identical structurally, when studied at the protein, mRNA, and cDNA level. Thus, CD73 is an interesting example of a molecule which lacks structural variants but yet has a wide diversity of biological functions. We suggest that the ligand- induced shedding of lymphocyte CD73 represents an important and novel means of controlling lymphocyte– EC interactions.
MAP Kinase Is Required for the Spindle Assembly Checkpoint but Is Dispensable for the Normal M Phase Entry and Exit in Xenopus Egg Cell Cycle Extracts
Authors: Takenaka Katsuya , Gotoh Yukiko , Nishida Eisuke
Published: July 2002

In Xenopus laevis egg cell cycle extracts that mimic early embryonic cell cycles, activation of MAP kinase and MAP kinase kinase occurs in M phase, slightly behind that of maturation promoting factor. To examine the possible role of MAP kinase in the in vitro cell cycle, we depleted the extracts of MAP kinase by using anti–Xenopus MAP kinase antibody. Like in the mock-treated extracts, the periodic activation and deactivation of MPF occurred normally in the MAP kinase–depleted extracts, suggesting that MAP kinase is dispensable for the normal M phase entry and exit in vitro. It has recently been reported that microtubule depolymerization by nocodazole treatment can block exit from mitosis in the extracts if enough sperm nuclei are present, and that the addition of MAP kinase– specific phosphatase MKP-1 overcomes this spindle assembly checkpoint, suggesting the involvement of MAP kinase in the checkpoint signal transduction. We show here that the spindle assembly checkpoint mechanism cannot operate in the MAP kinase–depleted extracts. But, adding recombinant Xenopus MAP kinase to the MAP kinase–depleted extracts restored the spindle assembly checkpoint. These results indicate unambiguously that classical MAP kinase is required for the spindle assembly checkpoint in the cell cycle extracts. In addition, we show that strong activation of MAP kinase by the addition of a constitutively active MAP kinase kinase kinase in the absence of sperm nuclei and nocodazole, induced mitotic arrest in the extracts. Therefore, activation of MAP kinase alone is sufficient for inducing the mitotic arrest in vitro.
Spontaneous Cell Fusion in Macrophage Cultures Expressing High Levels of the P2Z/P2X7 Receptor
Authors: Chiozzi Paola , Sanz Juana M. , Ferrari Davide , Falzoni Simonetta , Aleotti Arrigo , Buell Gary N. , Collo Ginetta , Virgilio Francesco Di
Published: July 2002

Mouse and human macrophages express a plasma membrane receptor for extracellular ATP named P2Z/P2X7. This molecule, recently cloned, is endowed with the intriguing property of forming an aqueous pore that allows transmembrane fluxes of hydrophylic molecules of molecular weight below 900. The physiological function of this receptor is unknown. In a previous study we reported experiments suggesting that the P2Z/P2X7 receptor is involved in the formation of macrophage-derived multinucleated giant cells (MGCs; Falzoni, S., M. Munerati, D. Ferrari, S. Spisani, S. Moretti, and F. Di Virgilio. 1995. J. Clin. Invest. 95:1207– 1216). We have selected several clones of mouse J774 macrophages that are characterized by either high or low expression of the P2Z/P2X7 receptor and named these clones P2Zhyper or P2Zhypo, respectively. P2Zhyper, but not P2Zhypo, cells grown to confluence in culture spontaneously fuse to form MGCs. As previously shown for human macrophages, fusion is inhibited by the P2Z/P2X7 blocker oxidized ATP. MGCs die shortly after fusion through a dramatic process of cytoplasmic sepimentation followed by fragmentation. These observations support our previous hypothesis that the P2Z/P2X7 receptor is involved in macrophage fusion.
Positive and Negative Regulation of Muscle Cell Identity by Members of the hedgehog and TGF-β Gene Families
Authors: Du Shao Jun , Devoto Stephen H. , Westerfield Monte , Moon Randall T.
Published: July 2002

We have examined whether the development of embryonic muscle fiber type is regulated by competing influences between Hedgehog and TGF-β signals, as previously shown for development of neuronal cell identity in the neural tube. We found that ectopic expression of Hedgehogs or inhibition of protein kinase A in zebrafish embryos induces slow muscle precursors throughout the somite but muscle pioneer cells only in the middle of the somite. Ectopic expression in the notochord of Dorsalin-1, a member of the TGF-β superfamily, inhibits the formation of muscle pioneer cells, demonstrating that TGF-β signals can antagonize the induction of muscle pioneer cells by Hedgehog. We propose that a Hedgehog signal first induces the formation of slow muscle precursor cells, and subsequent Hedgehog and TGF-β signals exert competing positive and negative influences on the development of muscle pioneer cells.
Evidence for a Conformational Change in Actin Induced by Fimbrin (N375) Binding
Authors: Hanein Dorit , Matsudaira Paul , DeRosier David J.
Published: July 2002

Fimbrin belongs to a superfamily of actin cross-linking proteins that share a conserved 27-kD actin-binding domain. This domain contains a tandem duplication of a sequence that is homologous to calponin. Calponin homology (CH) domains not only cross-link actin filaments into bundles and networks, but they also bind intermediate filaments and some signal transduction proteins to the actin cytoskeleton. This fundamental role of CH domains as a widely used actin-binding domain underlines the necessity to understand their structural interaction with actin. Using electron cryomicroscopy, we have determined the three-dimensional structure of F-actin and F-actin decorated with the NH2-terminal CH domains of fimbrin (N375). In a difference map between actin filaments and N375-decorated actin, one end of N375 is bound to a concave surface formed between actin subdomains 1 and 2 on two neighboring actin monomers. In addition, a fit of the atomic model for the actin filament to the maps reveals the actin residues that line, the binding surface. The binding of N375 changes actin, which we interpret as a movement of subdomain 1 away from the bound N375. This change in actin structure may affect its affinity for other actin-binding proteins and may be part of the regulation of the cytoskeleton itself. Difference maps between actin and actin decorated with other proteins provides a way to look for novel structural changes in actin.
β-Spectrin Is Colocalized with Both Voltage-gated Sodium Channels and AnkyrinG at the Adult Rat Neuromuscular Junction
Authors: Wood S.J. , Slater C.R.
Published: July 2002

Voltage-gated sodium channels (VGSCs) are concentrated in the depths of the postsynaptic folds at mammalian neuromuscular junctions (NMJs) where they facilitate action potential generation during neuromuscular transmission. At the nodes of Ranvier and the axon hillocks of central neurons, VGSCs are associated with the cytoskeletal proteins, β-spectrin and ankyrin, which may help to maintain the high local density of VGSCs. Here we show in skeletal muscle, using immunofluorescence, that β-spectrin is precisely colocalized with both VGSCs and ankyrinG, the nodal isoform of ankyrin. In en face views of rat NMJs, acetylcholine receptors (AChRs), and utrophin immunolabeling are organized in distinctive linear arrays corresponding to the crests of the postsynaptic folds. In contrast, β-spectrin, VGSCs, and ankyrinG have a punctate distribution that extends laterally beyond the AChRs, consistent with a localization in the depths of the folds. Double antibody labeling shows that β-spectrin is precisely colocalized with both VGSCs and ankyrinG at the NMJ. Furthermore, quantification of immunofluorescence in labeled transverse sections reveals that β-spectrin is also concentrated in perijunctional regions, in parallel with an increase in labeling of VGSCs and ankyrinG, but not of dystrophin. These observations suggest that interactions with β-spectrin and ankyrinG help to maintain the concentration of VGSCs at the NMJ and that a common mechanism exists throughout the nervous system for clustering VGSCs at a high density.
6-C-kine (SLC), a Lymphocyte Adhesion-triggering Chemokine Expressed by High Endothelium, Is an Agonist for the MIP-3β Receptor CCR7
Authors: Campbell James J. , Bowman Edward P. , Murphy Kristine , Youngman Kenneth R. , Siani Michael A. , Thompson Darren A. , Wu Lijun , Zlotnik Albert , Butcher Eugene C.
Published: July 2002

The β chemokine known as 6-C-kine, secondary lymphoid-tissue chemokine (SLC), TCA4, or Exodus-2 (herein referred to as 6CK/SLC) can trigger rapid integrin-dependent arrest of lymphocytes rolling under physiological shear and is highly expressed by high endothelial venules, specialized vessels involved in lymphocyte homing from the blood into lymph nodes and Peyer's patches. We show that 6CK/SLC is an agonist for the lymphocyte chemoattractant receptor, CCR7 (EBI-1, BLR-2), previously described as a receptor for the related β chemokine MIP-3β (ELC or Exodus-3). Moreover, 6CK/SLC and MIP-3β attract the same major populations of circulating lymphocytes, including naive and memory T cells > B cells (but not natural killer cells); desensitization to MIP-3β inhibits lymphocyte chemotaxis to 6CK/SLC but not to the α chemokine SDF-1 (stromal cell–derived factor); and 6CK/SLC competes for MIP-3β binding to resting mouse lymphocytes. The findings suggest that the majority of circulating lymphocytes respond to 6CK/SLC and MIP-3β in large part through their common receptor CCR7 and that these molecules may be important mediators of physiological lymphocyte recirculation in vivo.
Differential Subcellular Localization of Protein Phosphatase-1 α, γ1, and δ Isoforms during Both Interphase and Mitosis in Mammalian Cells
Authors: Andreassen Paul R. , Lacroix Françoise B. , Villa-Moruzzi Emma , Margolis Robert L.
Published: July 2002

Protein phosphatase-1 (PP-1) is involved in the regulation of numerous metabolic processes in mammalian cells. The major isoforms of PP-1, α, γ1, and δ, have nearly identical catalytic domains, but they vary in sequence at their extreme NH2 and COOH termini. With specific antibodies raised against the unique COOH-terminal sequence of each isoform, we find that the three PP-1 isoforms are each expressed in all mammalian cells tested, but that they localize within these cells in a strikingly distinct and characteristic manner. Each isoform is present both within the cytoplasm and in the nucleus during interphase. Within the nucleus, PP-1 α associates with the nuclear matrix, PP-1 γ1 concentrates in nucleoli in association with RNA, and PP-1 δ localizes to nonnucleolar whole chromatin. During mitosis, PP-1 α is localized to the centrosome, PP-1 γ1 is associated with microtubules of the mitotic spindle, and PP-1 δ strongly associates with chromosomes. We conclude that PP-1 isoforms are targeted to strikingly distinct and independent sites in the cell, permitting unique and independent roles for each of the isoforms in regulating discrete cellular processes.
Apical Polarity of N-CAM and EMMPRIN in Retinal Pigment Epithelium Resulting from Suppression of Basolateral Signal Recognition
Authors: Marmorstein Alan D. , Gan Yunbo C. , Bonilha Vera L. , Finnemann Silvia C. , Csaky Karl G. , Rodriguez-Boulan Enrique
Published: July 2002

Retinal pigment epithelial (RPE) cells apically polarize proteins that are basolateral in other epithelia. This reversal may be generated by the association of RPE with photoreceptors and the interphotoreceptor matrix, postnatal expansion of the RPE apical surface, and/or changes in RPE sorting machinery. We compared two proteins exhibiting reversed, apical polarities in RPE cells, neural cell adhesion molecule (N-CAM; 140-kD isoform) and extracellular matrix metalloproteinase inducer (EMMPRIN), with the cognate apical marker, p75-neurotrophin receptor (p75-NTR). N-CAM and p75-NTR were apically localized from birth to adulthood, contrasting with a basolateral to apical switch of EMMPRIN in developing postnatal rat RPE. Morphometric analysis demonstrated that this switch cannot be attributed to expansion of the apical surface of maturing RPE because the basolateral membrane expanded proportionally, maintaining a 3:1 apical/basolateral ratio. Kinetic analysis of polarized surface delivery in MDCK and RPE-J cells showed that EMMPRIN has a basolateral signal in its cytoplasmic tail recognized by both cell lines. In contrast, the basolateral signal of N-CAM is recognized by MDCK cells but not RPE-J cells. Deletion of N-CAM's basolateral signal did not prevent its apical localization in vivo. The data demonstrate that the apical polarity of EMMPRIN and N-CAM in mature RPE results from suppressed decoding of specific basolateral signals resulting in randomized delivery to the cell surface.
Extracellular Matrix Regulates Apoptosis in Mammary Epithelium through a Control on Insulin Signaling
Authors: Farrelly Nadia , Lee Yi-Ju , Oliver Janine , Dive Caroline , Streuli Charles H.
Published: July 2002

Adherent epithelial cells require interactions with the extracellular matrix for their survival, though the mechanism is ill-defined. In long term cultures of primary mammary epithelial cells, a laminin-rich basement membrane (BM) but not collagen I suppresses apoptosis, indicating that adhesion survival signals are specific in their response (Pullan et al. 1996. J. Cell Sci. 109:631–642). We now demonstrate that the signal from BM is mediated by integrins and requires both the α6 and β1 subunits. In addition, a hormonal signal from insulin or insulin-like growth factors, but not hydrocortisone or prolactin, is necessary to suppress mammary cell apoptosis, indicating that BM and soluble factors cooperate in survival signaling. Insulin induced autophosphorylation of its receptor whether mammary cells were cultured on collagen I or BM substrata. However, both the tyrosine phosphorylation of insulin receptor substrate-1 and its association with phosphatidylinositol 3-kinase were enhanced in cells cultured on BM, as was the phosphorylation of the phosphatidylinositol 3-kinase effector, protein kinase B. These results suggest a novel extracellular matrix–dependent restriction point in insulin signaling in mammary epithelial cells. The proximal signal transduction event of insulin receptor phosphorylation is not dependent on extracellular matrix, but the activation of downstream effectors requires adhesion to BM. Since phosphatidylinositol 3-kinase was required for mammary epithelial cell survival, we propose that a possible mechanism for BM-mediated suppression of apoptosis is through its facilitative effects on insulin signaling.
Erg30, a Vap-33–Related Protein, Functions in Protein Transport Mediated by Copi Vesicles
Authors: Soussan Lior , Burakov Darya , Daniels Mathew P. , Toister-Achituv Mira , Porat Amir , Yarden Yossef , Elazar Zvulun
Published: July 2002

Intracellular transport of newly synthesized and mature proteins via vesicles is controlled by a large group of proteins. Here we describe a ubiquitous rat protein—endoplasmic reticulum (ER) and Golgi 30-kD protein (ERG30)—which shares structural characteristics with VAP-33, a 33-kD protein from Aplysia californica which was shown to interact with the synaptic protein VAMP. The transmembrane topology of the 30-kD ERG30 corresponds to a type II integral membrane protein, whose cytoplasmic NH2 terminus contains a predicted coiled-coil motif. We localized ERG30 to the ER and to pre-Golgi intermediates by biochemical and immunocytochemical methods. Consistent with a role in vesicular transport, anti-ERG30 antibodies specifically inhibit intra-Golgi transport in vitro, leading to significant accumulation of COPI-coated vesicles. It appears that ERG30 functions early in the secretory pathway, probably within the Golgi and between the Golgi and the ER.
Integrating the Actin and Vimentin Cytoskeletons
Authors: Correia Ivan , Chu Donald , Chou Ying-Hao , Goldman Robert D. , Matsudaira Paul
Published: July 2002

Cells adhere to the substratum through specialized structures that are linked to the actin cytoskeleton. Recent studies report that adhesion also involves the intermediate filament (IF) and microtubule cytoskeletons, although their mechanisms of interaction are unknown. Here we report evidence for a novel adhesion-dependent interaction between components of the actin and IF cytoskeletons. In biochemical fractionation experiments, fimbrin and vimentin coprecipitate from detergent extracts of macrophages using vimentin- or fimbrin-specific antisera. Fluorescence microscopy confirms the biochemical association. Both proteins colocalized to podosomes in the earliest stages of cell adhesion and spreading. The complex is also found in filopodia and retraction fibers. After detergent extraction, fimbrin and vimentin staining of podosomes, filopodia, and retraction fibers are lost, confirming that the complex is localized to these structures. A 1:4 stoichiometry of fimbrin binding to vimentin and a low percentage (1%) of the extracted vimentin suggest that fimbrin interacts with a vimentin subunit. A fimbrin-binding site was identified in the NH2-terminal domain of vimentin and the vimentin binding site at residues 143–188 in the CH1 domain of fimbrin. Based on these observations, we propose that a fimbrin–vimentin complex may be involved in directing the assembly of the vimentin cytoskeleton at cell adhesion sites.
DNA Methyltransferase Is Actively Retained in the Cytoplasm during Early Development
Authors: Cardoso M. Cristina , Leonhardt Heinrich
Published: July 2002

The overall DNA methylation level sharply decreases from the zygote to the blastocyst stage despite the presence of high levels of DNA methyltransferase (Dnmt1). Surprisingly, the enzyme is localized in the cytoplasm of early embryos despite the presence of several functional nuclear localization signals. We mapped a region in the NH2-terminal, regulatory domain of Dnmt1 that is necessary and sufficient for cytoplasmic retention during early development. Altogether, our results suggest that Dnmt1 is actively retained in the cytoplasm, which prevents binding to its DNA substrate in the nucleus and thereby contributes to the erasure of gamete-specific epigenetic information during early mammalian development.
Dual Palmitoylation of Psd-95 Mediates Its Vesiculotubular Sorting, Postsynaptic Targeting, and Ion Channel Clustering
Authors: El-Husseini Alaa E. , Craven Sarah E. , Chetkovich Dane M. , Firestein Bonnie L. , Schnell Eric , Aoki Chiye , Bredt David S.
Published: July 2002

Postsynaptic density-95 (PSD-95/SAP-90) is a palmitoylated peripheral membrane protein that scaffolds ion channels at excitatory synapses. To elucidate mechanisms for postsynaptic ion channel clustering, we analyzed the cellular trafficking of PSD-95. We find that PSD-95 transiently associates with a perinuclear membranous compartment and traffics with vesiculotubular structures, which migrate in a microtubule-dependent manner. Trafficking of PSD-95 with these vesiculotubular structures requires dual palmitoylation, which is specified by five consecutive hydrophobic residues at the NH2 terminus. Mutations that disrupt dual palmitoylation of PSD-95 block both ion channel clustering by PSD-95 and its synaptic targeting. Replacing the palmitoylated NH2 terminus of PSD-95 with alternative palmitoylation motifs at either the NH2 or COOH termini restores ion channel clustering also induces postsynaptic targeting, respectively. In brain, we find that PSD-95 occurs not only at PSDs but also in association with intracellular smooth tubular structures in dendrites and spines. These data imply that PSD-95 is an itinerant vesicular protein; initial targeting of PSD-95 to an intracellular membrane compartment may participate in postsynaptic ion channel clustering by PSD-95.
Promyelocytic Leukemia (Pml) Nuclear Bodies Are Protein Structures That Do Not Accumulate RNA
Authors: Boisvert François-Michel , Hendzel Michael J. , Bazett-Jones David P.
Published: July 2002

The promyelocytic leukemia (PML) nuclear body (also referred to as ND10, POD, and Kr body) is involved in oncogenesis and viral infection. This subnuclear domain has been reported to be rich in RNA and a site of nascent RNA synthesis, implicating its direct involvement in the regulation of gene expression. We used an analytical transmission electron microscopic method to determine the structure and composition of PML nuclear bodies and the surrounding nucleoplasm. Electron spectroscopic imaging (ESI) demonstrates that the core of the PML nuclear body is a dense, protein-based structure, 250 nm in diameter, which does not contain detectable nucleic acid. Although PML nuclear bodies contain neither chromatin nor nascent RNA, newly synthesized RNA is associated with the periphery of the PML nuclear body, and is found within the chromatin-depleted region of the nucleoplasm immediately surrounding the core of the PML nuclear body. We further show that the RNA does not accumulate in the protein core of the structure. Our results dismiss the hypothesis that the PML nuclear body is a site of transcription, but support the model in which the PML nuclear body may contribute to the formation of a favorable nuclear environment for the expression of specific genes.
Intracellular Ph Regulation by Na+/H+ Exchange Requires Phosphatidylinositol 4,5-Bisphosphate
Authors: Aharonovitz Orit , Zaun Hans C. , Balla Tamas , York John D. , Orlowski John , Grinstein Sergio
Published: July 2002

The carrier-mediated, electroneutral exchange of Na+ for H+ across the plasma membrane does not directly consume metabolic energy. Nevertheless, acute depletion of cellular ATP markedly decreases transport. We analyzed the possible involvement of polyphosphoinositides in the metabolic regulation of NHE1, the ubiquitous isoform of the Na+/H+ exchanger. Depletion of ATP was accompanied by a marked reduction of plasmalemmal phosphatidylinositol 4,5-bisphosphate (PIP2) content. Moreover, sequestration or hydrolysis of plasmalemmal PIP2, in the absence of ATP depletion, was associated with profound inhibition of NHE1 activity. Examination of the primary structure of the COOH-terminal domain of NHE1 revealed two potential PIP2-binding motifs. Fusion proteins encoding these motifs bound PIP2 in vitro. When transfected into antiport-deficient cells, mutant forms of NHE1 lacking the putative PIP2-binding domains had greatly reduced transport capability, implying that association with PIP2 is required for optimal activity. These findings suggest that NHE1 activity is modulated by phosphoinositides and that the inhibitory effect of ATP depletion may be attributable, at least in part, to the accompanying net dephosphorylation of PIP2.
A Fast Signal–Induced Activation of Poly(Adp-Ribose) Polymerase
Authors: Homburg S. , Visochek L. , Moran N. , Dantzer F. , Priel E. , Asculai E. , Schwartz D. , Rotter V. , Dekel N. , Cohen-Armon M.
Published: July 2002

We present the first evidence for a fast activation of the nuclear protein poly(ADP-ribose) polymerase (PARP) by signals evoked in the cell membrane, constituting a novel mode of signaling to the cell nucleus. PARP, an abundant, highly conserved, chromatin-bound protein found only in eukaryotes, exclusively catalyzes polyADP-ribosylation of DNA-binding proteins, thereby modulating their activity. Activation of PARP, reportedly induced by formation of DNA breaks, is involved in DNA transcription, replication, and repair. Our findings demonstrate an alternative mechanism: a fast activation of PARP, evoked by inositol 1,4,5,-trisphosphate–Ca2+ mobilization, that does not involve DNA breaks. These findings identify PARP as a novel downstream target of phospholipase C, and unveil a novel fast signal–induced modification of DNA-binding proteins by polyADP-ribosylation.