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Biomedical subjects

J N Hughes

Publications and source records attributed to J N Hughes.

17 recordsLinked to original sources
PubMed2001

Implications of aggressive children's positively biased relatedness views for future relationships.

The present study examined the tendency of aggressive children to generalize the positive bias in their perceptions of relatedness across different interpersonal relationships. Secondly, it examined the implications of distorted perceptions of relatedness for quality of aggressive children's future relationships. Subjects included 62 second and third grade children nominated and rated by teachers as aggressive. Self- and others' appraisals of relationship quality were gathered across four interpersonal domains (i.e., mother, teacher, mentor, and peer). Children's positively biased perceptions of social relatedness were concordant across adult relationship domains but not across the peer domain, suggesting that children's relationships with adults and peers represent somewhat distinct socialization contexts. As expected, children who inflate levels of social relatedness establish less close relationships with novel partners (mentors). The findings emphasize the need for clinicians to focus on mental representations while planning interventions with aggressive children.

Adult↗
PubMed2001

The effect of hexafluorocyclobutene on rat bronchoalveolar lavage fluid surfactant phospholipids and alveolar type II cells.

Hexafluorocyclobutene (HFCB), a reactive organohalogen gas, causes overwhelming pulmonary oedema. We investigated its effect on the rat lung surfactant system, comparing its action on type II pneumocytes with air-exposed rats. The inflammatory cell population and protein content of bronchoalveolar lavage fluid was analysed following exposure to air or HFCB (LCt30). Six rat lung phospholipids were measured by high-performance liquid chromatography, following solid phase extraction (SPE) from lavage fluid. Transmission electron microscopy (TEM) was used to visualise effects on alveolar type II cell ultrastructure. HFCB caused changes in cell populations and increased lavage fluid protein compared to controls, suggesting a permeability oedema. Changes in the total amount and percentage composition (sustained decrease in phosphatidylglycerol and phosphatidylcholine) of surfactant phospholipids also occurred. TEM observations indicated no direct ultrastructural damage to the type II cells, but showed initial, rapid release of surfactant into the alveolar space. HFCB altered the surfactant system in a manner similar to that shown following another reactive organohalogen gas, perfluoroisobutene (PFIB), but differently to that after phosgene. These differences suggest different mechanisms of action even though pulmonary oedema is the final injury for all gases. Better knowledge of the mechanisms involved will improve prospects for prophylactic/therapeutic intervention.

Animals↗
PubMed2001

Type 2 diabetes locus on 12q15. Further mapping and mutation screening of two candidate genes.

We recently reported evidence of a novel type 2 diabetes locus placed on chromosome 12q15 between markers D12S375 and D12S1684 (Diabetes 48:2246-2251, 1999). Four multigenerational families having logarithm of odds (LOD) scores >1.0 in the original analysis were genotyped for 11 additional markers in this interval to refine this mapping; this allowed us to narrow the linked region to the interval between markers D12S1693 and D12S326. In a multipoint parametric analysis using the VITESSE software, the LOD score for linkage at this location reached 3.1 in one of these families. This interval contains the gene for protein tyrosine phosphatase receptor type R (PTPRR)--a protein that may be involved in both insulin secretion and action. After determining PTPRR exon-intron structure, we identified several polymorphisms in this gene but no mutation segregating with diabetes. The search for mutations was also negative for carboxypeptidase M (CPM)--another candidate gene mapped to this region. In summary, our data provide further evidence for the existence of a type 2 diabetes locus on chromosome 12q15. This locus, however, does not appear to correspond to the PTPRR or CPM, although a contribution of mutations in regulatory regions cannot be excluded at this time.

Adolescent↗
PubMed1999

Influence of the teacher-student relationship on childhood conduct problems: a prospective study.

Examined the influence of the quality of the teacher-student relationship on children's subsequent levels of aggression in a sample of 61 second and third-grade children nominated and rated by their teachers as aggressive. The stability of teachers' and children's reports of relationships quality across academic years was in the low to moderate range. Teachers and children showed little agreement in their reports of relationship quality. Teachers' and children's reports of relationship quality in year 1 (Y1) predicted teacher-rated aggression the following year, controlling for Y1 ratings of aggression. Teachers' reports of relationship quality across Y1 and Y2 predicted peer-rated aggression, but not teacher-rated aggression, in Y3, controlling for Y1 aggression. Consistent with a buffering role for teacher-student relationships, a positive teacher-student relationship was of greatest benefit to children whose mothers reported rejecting parenting histories. We discuss implications for school-based prevention programs.

Aggression↗
PubMed1999

United we stand, divided we fall: the education and training needs of clinical child psychologists.

Reviews efforts to delineate training needs for psychologists who are providing clinical services to children, adolescents, and families. In particular, this article (a) describes efforts of clinical child and other psychologists who work with children, adolescents, and families to develop education and training guidelines; (b) discusses the overlap among various child and adolescent providers within psychology; and (c) highlights several key competencies that have been identified as important for all psychologists in practice roles with children and adolescents. In particular, we emphasize the need for greater collaboration and integration among various psychological specialties that focus on children, adolescents, and families and for greater system-wide discussion of training needs and priorities.

Adolescent↗
PubMed1999

The self-systems of aggressive children: a cluster-analytic investigation.

The purpose of the present study was to identify clinically relevant subtypes of aggressive children based on measures of children's self-systems and significant others' perceptions of relationship quality. In a sample of aggressive second- and third-graders, a cluster analysis of these children's perceptions of support and significant others' (mother, teacher, and peers) perceptions of relationship quality revealed one subgroup in which self- and other-ratings were both below the group mean (concordant-negative), one in which both were above the sample mean (concordant-positive), and one in which they were discrepant (high child-report and low other-report). All three clusters were rated as more aggressive than controls. However, children in the discrepant group were rated as considerably more aggressive and delinquent than those in the two concordant clusters, who did not differ from each other on measures of internalizing and externalizing behaviors. Results are discussed from an attachment perspective and in terms of the clinical significance of this self-other discrepancy.

Aggression↗
PubMed1997

A positive view of self: risk or protection for aggressive children?

Children's ratings of competence and relationship quality were used to examine the association between idealized or inflated self-perceptions and level of aggression. Participants were 62 aggressive and 53 nonaggressive second and third graders. Ratings of competence were based on the Pictorial Scale of Perceived Competence and Social Acceptance for Young Children; ratings of relationship quality were drawn from the Social Support Appraisals Scale and the Network of Relationships Inventory. External ratings of competence and relationship quality were obtained from mothers, teachers, and peers. Compared to children who were nonaggressive, aggressive children were more likely to rate personal competence and relationship quality in a perfect or idealized manner and to show less differentiation in their ratings of competence and relationship quality. Aggressive children's self-rated competence and relationship quality were also inflated relative to the ratings made by others, whereas the self-ratings of nonaggressive children tended to be underestimates of their functioning. The tendency for aggressive children to idealize and to inflate ratings of competence and relationship quality was associated with higher levels of aggression. For aggressive children, a highly positive self-view is construed--not as a protective factor or measurement error--but as a defensive posture that places the child at added risk and that impedes the progress of psychosocial interventions.

Aggression↗
PubMed1996

Morphology of ricin and abrin exposed endothelial cells is consistent with apoptotic cell death.

Cultures of bovine pulmonary endothelial (BPE) cells were exposed to LC70 doses of ricin or abrin (15.5 and 4.5 pM respectively) over a period of up to 40 h. The viability of the cultures (as determined by the neutral red (NR) dye retention assay) declined after 6 h exposure to the toxins. From 15 h onwards, cellular material in toxin exposed cultures became detached from the substratum of the culture vessels. Hoffman modulation contrast photomicrography showed that this process was due to ricin and abrin exposed cells collapsing into membrane bound vesicles which retained the NR dye, became detached and floated into the medium. These apoptotic-like structural changes were further investigated by transmission electron microscopy (TEM) and by agarose gel electrophoresis of DNA from control and exposed cultures. Many of the characteristic changes associated with apoptotic cell death were seen using TEM, including heterochromatin condensation at the nuclear periphery, crenulation of the nuclear membrane and progressive degeneration of residual nuclear and cytoplasmic structures. The plasma membrane of many cells remained intact, and contained nuclear and cytoplasmic debris. Agarose gel electrophoresis of DNA extracted from toxin-treated cells revealed oligonucleosome sized DNA fragments, characteristic of apoptosis, from adherent cells at 7 h and both adherent and floating populations when harvested from 15 h; DNA from unexposed control cells did not show this fragmentation. The identification of apoptosis as being a significant additional mechanism of toxicity following exposure to ricin and abrin holotoxins raises the possibility of developing new therapeutic strategies against poisoning by these phytotoxins.

Abrin↗
PubMed1993

Glycation of brain actin in experimental diabetes.

Actin is a neuronal protein involved in axonal transport and nerve regeneration, both of which are known to be impaired in experimental diabetes. To determine if actin is subject to glycation, we rendered rats diabetic by injection of streptozotocin. Two or 6 weeks later brains were removed and a preparation of cytoskeletal proteins was analyzed by two-dimensional polyacrylamide gel electrophoresis. Brains from diabetic animals contained an extra polypeptide that migrated close to actin and reacted with monoclonal antibody C4 against actin. It was also found in a preparation of soluble synaptic proteins from diabetic rat brain, indicating that it was at least partly neuronal in origin. This polypeptide could be produced by incubation of cytoskeletal proteins from brains of nondiabetic rats with glucose-6-phosphate in vitro. The appearance of this glycated actin in diabetic animals was prevented by administration of insulin for a period of 6 weeks. We could not detect any effect of glycation in vitro on the ability of muscle G-actin to form F-actin filaments and its significance for the function of actin remains to be determined. The finding that glycation of platelet-derived actin from diabetic patients was significantly increased implies that the abnormality may also occur in clinical diabetes.

Actins↗
PubMed1991

Children's attributions for peers' positive behaviors: social status differences.

The purpose of this study was to investigate differences between aggressive-rejected and nonaggressive-cooperative boys in their attributions for peers' positive behaviors. In individual interviews, 27 aggressive-rejected and 27 nonaggressive-accepted boys were presented with 10 vignettes and a real-life situation in which a peer's action resulted in a favorable outcome for another peer or for the subject. Subject's attributions for the peer's behavior were elicited with open-ended probes. Analysis of variance indicated that the groups did not differ in their tendency to infer positive intentions in the hypothetical story condition. In the real-life situation, aggressive-rejected boys were less likely to infer positive intentionality than were the nonaggressive-accepted boys. Boys' responses across the two conditions (hypothetical and real life) were moderately consistent.

Aggression↗
PubMed1991

Effects of experimental sarin intoxication on the morphology of the mouse diaphragm: a light and electron microscopical study.

A sublethal dose of sarin (GB, isopropyl methylphosphonofluoridate) was administered to mice. The animals were killed up to 28 days after dosing. Following excision, diaphragms were divided into two halves and used for ultrastructural examination and light microscopy. Planar sections of diaphragm showed muscle fibre degeneration and predominantly mononuclear infiltration, notably at 24 h. Semithin toluidine blue-stained sections and ultrastructural studies demonstrated hypercontraction with gross disruption of sarcomeres including loss of Z and A bands, which appeared to be associated with neuromuscular junctions. All changes were rapidly regressing by 7 days.

Animals↗
PubMed1990

Evaluation of subclinical depression in children using self-, peer-, and teacher-report measures.

This study reports on several classification issues utilizing the Children's Depression Inventory (CDI), the Child Behavior Checklist-Teacher Form (CBCL-T), and the Peer Nomination Inventory of Depression (PNID). The first sample contained 752 public school children in grades 5, 6, and 9. A second sample of 142 fifth-graders was included to have an additional PNID comparison group. Results revealed moderate correlations between the CDI and the CBCL-T and PNID. Use of multiple criteria for selecting children as depressed was discussed, and selection rates using multiple measures with either strict or lenient cutoff scores were given. Normative data on the PNID were evaluated, and it was suggested that norms for the PNID may not be generalizable to other samples. Finally, race and gender analyses showed that CDI scores for females were significantly higher than for males, whereas CDI scores for Hispanics were significantly higher than for non-Hispanic whites. However, Omega-squared analyses for these two variables showed this to be of little practical significance.

Adolescent↗
PubMed1989

Validation of a role-play measure of children's social skills.

A videotape-administered role-play test of children's social skills was developed and its psychometric properties tested. Performance criteria for the test were derived from popular children's ratings of the effectiveness of different role-play responses. The test was administered to 157 fourth- and fifth-grade boys and girls who had been classified as popular, average, neglected, or rejected, on the basis of sociometric testing. The test evidenced good interrater, test-retest, and internal consistency reliabilities. Children's role-play performance correlated significantly with teacher ratings of social competence and with peer-liking ratings. Neglected children performed more poorly on the role-play test than popular children. When differences in intelligence among social status groups were statistically controlled, social status groups did not differ on the role-play test. Results of the discriminant analyses support the conclusion that teacher ratings are better than role-play tests for identifying rejected children, whereas role-play tests and measures of intelligence appear more accurate than teacher ratings for identifying neglected children.

Child↗