Pathology and Virus Distribution in the Lung and Lymphoid Tissues of Pigs Experimentally Inoculated with Three Distinct Type 1 PRRS Virus Isolates of Varying Pathogenicity.

Porcine reproductive and respiratory syndrome (PRRS) continues to be the most economically important disease of swine worldwide. The appearance of highly pathogenic PRRS virus (PRRSV) strains in Europe and Asia has raised concerns about this disease and initiated increased efforts to understand the pathogenesis. In this study, we have compared the pathology and the virus distribution in tissues of pigs experimentally inoculated with three different genotype 1 PRRSV isolates. Sixty 5-week-old pigs were inoculated intranasally with a) the Lelystad virus (LV), b) a field strain from the UK causing respiratory clinical signs (UK) or c) a highly pathogenic strain from Belarus (BE). Sixteen animals were mock-infected and used as controls. The animals were euthanized at 3, 7 and 35 days post-infection (dpi), and lung and lymphoid tissues collected for histopathological examination and PRRSV detection by immunohistochemistry (IHC). Histopathological lesions consisted of interstitial pneumonia with mononuclear cell infiltrates in the lungs, lymphoid depletion, apoptosis and follicular hyperplasia in the spleen, lymph nodes and tonsil and lymphoid depletion in the thymus. Porcine reproductive and respiratory syndrome virus was detected mainly in monocytes-macrophages. BE-infected animals showed the highest pathological scores and the highest presence of virus at 3 and 7 dpi, followed by the UK field strain and then LV. Moderate lesions were observed at 35 dpi with lesser detection of PRRSV by IHC in each infected group. The highly pathogenic BE strain induced more severe pathology in both lungs and lymphoid organs of pigs compared with the classic field isolate and the prototype LV. The increased severity of pathology was in correlation with the presence of a higher number of PRRSV-infected cells in the tissues.

Increased pathogenicity of European porcine reproductive and respiratory syndrome virus is associated with enhanced adaptive responses and viral clearance.

Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically important diseases of swine worldwide. Since its first emergence in 1987 the PRRS virus (PRRSV) has become particularly divergent with highly pathogenic strains appearing in both Europe and Asia. However, the underlying mechanisms of PRRSV pathogenesis are still unclear. This study sets out to determine the differences in pathogenesis between subtype 1 and 3 strains of European PRRSV (PRRSV-I), and compare the immune responses mounted against these strains. Piglets were infected with 3 strains of PRRSV-I: Lelystad virus, 215-06 a British field strain and SU1-bel from Belarus. Post-mortem examinations were performed at 3 and 7 days post-infection (dpi), and half of the remaining animals in each group were inoculated with an Aujeszky's disease (ADV) vaccine to investigate possible immune suppression resulting from PRRSV infection. The subtype 3 SU1-bel strain displayed greater clinical signs and lung gross pathology scores compared with the subtype 1 strains. This difference did not appear to be caused by higher virus replication, as viraemia and viral load in broncho-alveolar lavage fluid (BALF) were lower in the SU1-bel group. Infection with SU1-bel induced an enhanced adaptive immune response with greater interferon (IFN)-γ responses and an earlier PRRSV-specific antibody response. Infection with PRRSV did not affect the response to vaccination against ADV. Our results indicate that the increased clinical and pathological effect of the SU1-bel strain is more likely to be caused by an enhanced inflammatory immune response rather than higher levels of virus replication.

Children's attitudes and behavioral intentions toward a peer with autistic behaviors: does a brief educational intervention have an effect?

This study examined children's ratings of attitudes and behavioral intentions toward a peer presented with or without autistic behaviors. The impact of information about autism on these ratings was investigated as well as age and gender effects. Third- and sixth-grade children (N = 233) were randomly assigned to view a video of the same boy in one of three conditions: No Autism, Autism, or Autism/Information. Children at both grade levels showed less positive attitudes toward the child in the two autism conditions. In rating their own behavioral intentions, children showed no differences between conditions. However, in attributing intentions to their classmates, older children and girls gave lower ratings to the child in the autism conditions. Information about autism did not affect ratings of either attitudes or behavioral intentions as ascribed to self or others.

Children's attitudes and behavioral intentions toward a peer presented as obese: does a medical explanation for the obesity make a difference?

OBJECTIVE: To examine the effect of information on children's attitudes and behavioral intentions toward a peer presented as obese. METHODS: Children (N = 184) were randomly assigned to observe a video of a boy or girl in one of three conditions: average-weight, obese, obese with medical information explaining the obesity. They rated stereotypical attitudes on the Adjective Checklist and behavioral intentions on the Shared Activities Questionnaire (SAQ-B). RESULTS: Ratings were generally more favorable for the average-weight than for the obese condition. However, provision of medical information had a positive effect on attitudes toward the obese peer only for younger children and a negative effect on willingness of older children to share academic activities with the peer. Boys and girls showed more positive behavioral intentions toward the same-sex target child regardless of obesity condition. CONCLUSIONS: Information explaining obesity has a minimal positive effect on children's attitudes and behavioral intentions toward a peer presented as obese.

Children's willingness to share activities with a physically handicapped peer: am I more willing than my classmates?

OBJECTIVE: To examine factors affecting children's willingness to share activities with a peer presented as physically handicapped. METHOD: Participants were 120 elementary school children randomly assigned to view a video of an ambulatory child or the same child in a wheelchair. They rated, on the Shared Activities Questionnaire (SAQ), their own willingness (SAQ-Self) and their perceptions of classmates' willingness (SAQ-Others) to participate in activities with the child. RESULTS: SAQ-Self ratings were consistently higher for the peer in the wheelchair. On the SAQ-Others, differences favoring the child in the wheelchair disappeared, and ratings of this child were lower than SAQ-Self ratings. No interactions were found between ambulation status and age or rater gender or preference for type of shared activity. CONCLUSIONS: Children showed highly positive intentions toward a peer in a wheelchair, but intentions attributed to classmates were less positive, which suggests "social desirability" influenced their own ratings.

Adaptive and intellectual functioning in autistic and nonautistic retarded children.

This study examined the relationship between adaptive functioning on the Vineland Adaptive Behaviour Scale (VABS) and intellectual functioning on the Stanford-Binet Intelligence Scale, 4th edition (SB-IV) in autistic children and nonautistic retarded children of comparable CA and SB-IV composite score (IQ). The autistic group had lower scores than the retarded group in VABS adaptive composite, Socialization domain, and Communication domain, and SB-IV Verbal Reasoning area. VABS domain scores yielded higher classification rates than the SB-IV area scores in discriminating the two groups. Correlations between the two measures were much higher for the autistic group than for the retarded group. Results support the conclusion that the cognitive impairment in autism is reflected in greater impairment in adaptive behaviors than in mental retardation without autism.

Children's attitudes and behavioral intentions toward a peer with Tourette syndrome.

Examined children's ratings of attitudes and behavioral intentions toward a boy presented, on videotape, with or without symptoms of Tourette syndrome (TS). Effects of information about TS on these ratings were investigated as well as the influence of gender and grade. Children in Grades 3 and 5 were randomly assigned to one of three conditions: No TS, TS, or TS/information. On the attitude measure, children rated the peer presented with TS less positively than they did the peer presented without TS. On behavioral intention measures, no significant differences were found between conditions. Information about TS did not affect ratings. Implications of these findings as well as limitations of the study are discussed.

Perceived competence and behavioral adjustment of siblings of children with autism.

Compared 19 siblings of severely autistic children with 20 siblings of children with Down syndrome and 20 siblings of developmentally normal children. Results reveal that siblings of autistic children have more internalizing and externalizing behavior problems than siblings of developmentally normal children; however, the three groups did not differ significantly on measures of perceived self-competence or parents' report of social competence. Examination of demographic variables indicate that age of sibling and parents' marital satisfaction were associated with siblings' psychological functioning. Implications for future research are discussed.

A longitudinal study of children with Down syndrome who experienced early intervention programming.

BACKGROUND AND PURPOSE: The long-term motor, cognitive, and adaptive functioning of a sample of adolescents with Down syndrome who experienced an early intervention program was examined in this descriptive study. SUBJECTS: Ten children with Down syndrome (7 girls, 3 boys) who had participated in an early intervention program constituted the early intervention (EI) group. An age-matched group of children with Down syndrome (6 girls, 4 boys) who had not experienced an early intervention program served as a comparison group. METHODS: The EI group's motor functioning was compared with that of a normative sample used in the development of the Bruininks-Oseretsky Test of Motor Proficiency. The cognitive and adaptive skills of the EI group were compared with those of the comparison group. The children were assessed using the Stanford-Binet Intelligence Scale, the Vineland Social Maturity Scale, and the Bruininks-Oseretsky Test of Motor Proficiency. RESULTS: The EI group subjects fell below their chronological age levels in gross and fine motor skills; however, their mean gross motor skill levels exceeded their mean fine motor skill levels. The specific deficits in gross motor and fine motor skills, which were documented in a previous follow-up study on the same sample, continued to be areas of deficits (visual motor coordination, running speed, balance, and reaction time). The EI group subjects had significantly higher scores on measures of intellectual and adaptive functioning than did the children in the comparison group. The EI group subjects did not show the decline typically seen with age in adaptive functioning in individuals with Down syndrome. CONCLUSION AND DISCUSSION: Because of the design limitations, the differences between the groups should be interpreted with caution.

Psychosocial adaptation of fathers of children with autism, Down syndrome, and normal development.

Fathers have been largely neglected in previous research of families of autistic children. We compared fathers of 20 autistic, 20 Down syndrome, and 20 developmentally normal children on several measures of psychosocial adaptation. Groups were matched on child's adaptive behavior age equivalent, gender, birth order, family size, and SES. The three groups differed significantly on measures of intrapersonal and family functioning but not on social-ecological variables. Fathers of children with autism or Down syndrome reported more frequent use of wish-fulfilling fantasy and information seeking as coping strategies as well as more financial impact and disruption of family activities than did fathers of developmentally normal children. There were few significant differences between fathers of children with autism and those of children with Down syndrome. These results suggest that fathers adapt relatively well to the demands associated with raising a child with a developmental disability.

Concrete operational thought in children with learning disabilities and children with normal achievement.

This study compared Piagetian cognitive development in normal achieving children and two groups of children with learning disabilities designated as either auditory-linguistic or visual-spatial on the basis of Verbal-Performance IQ differences on the Wechsler Intelligence Scale for Children-Revised (WISC-R; 1974). The two groups with learning disabilities were matched with normal achieving controls on intelligence, socioeconomic status, sex, race, and age. Piagetian tasks measuring conservation, seriation, and classification were administered to each child to determine level of operative thought. The auditory-linguistic group scored significantly below normal controls in operativity, and significantly fewer were at a concrete operational level on a conservation of length task than were normal achieving children. The visual-spatial group did not differ significantly from normal controls. These results suggest that auditory-linguistic disabilities may be more detrimental than visual-spatial disabilities to development of operativity.

A comparative evaluation of adaptive behavior in children and adolescents with autism, Down syndrome, and normal development.

The adaptive behaviors of 20 autistic, 20 Down syndrome, and 20 developmentally normal children were compared using the Vineland Adaptive Behavior Scale. Unlike previous studies, we included a comparison group of very young normally developing children and matched subjects on overall adaptive behavior as well as several pertinent demographic characteristics. Findings revealed that, relative to children with Down syndrome or normal development, autistic children displayed significant and pervasive deficits in the acquisition of adaptive social skills, and greater variability in adaptive skills. These findings underscore the need to longitudinally assess the development of socialization in autistic children and further highlight the utility of the Vineland in operationally defining the nature of social dysfunction in autistic children.

Do autistic children differ from retarded and normal children in Piagetian sensorimotor functioning?

Piagetian sensorimotor functioning of 10 autistic, 10 retarded, and 10 normal children, closely matched on mental age, was assessed with the Dunst revision of the Uzgiris and Hunt scales of infant psychological development. The three groups showed no significant differences in overall performance or specific subtest performance as revealed by estimated developmental ages, number of failed items, and Piagetian stage levels. These findings, which are contrary to previous reports of early sensorimotor deficits specific to autism, suggest that the long-term cognitive deficits in autism are more in symbolic thinking, which does not emerge until the end of the sensorimotor period.

The autistic child and family functioning: a developmental-family systems perspective.

Autism is a severe, long-term developmental disorder that potentially has substantial influence on different aspects of the family system. Principles from family-systems theory are considered as they relate to the autistic child within the family. A selective and critical review is presented of research findings on the influence of the autistic child on the functioning and interactions of family members, including parents, siblings, and the family as a whole. Research findings are also reviewed on resources associated with successful family adaptation to the autistic child. Suggestions are offered for improved research to assess the relationship between certain child variables and measures of family functioning.

Autism and Piaget's theory: are the two compatible?

Autism is interpreted in Piagetian terms with particular reference to the question of whether the atypical cognitive development represents an exception to the similar sequence hypothesis. Findings from relevant research applying Piaget's theory to mental retardation, psychosis, and autism are reviewed. The apparent exceptions to the hypothesis presented in autistic individuals are explained by Piaget's two-factor theory of figurative versus operative functions. Many autistic individuals show an arrest in operative functions at the sensorimotor level while continuing to progress in figurative functions. The early arrest interferes with subsequent development of higher-level conceptual, symbolic, and social skills. Questions for research are offered.