Regional hypomyelination and dysplasia in transgenic mice with astrocyte-directed expression of interferon-gamma.

Interferon-gamma (IFN-gamma), traditionally associated with a variety of physiological and pathological processes of the immune system, manifests an array of biological effects on cells of the nervous system. Clinical and in vitro studies support a key role for IFN-gamma in the pathogenesis of immune-mediated demyelinating disorders such as multiple sclerosis (MS). To investigate the role of this cytokine within the central nervous system (CNS), transgenic mice were derived in which IFN-gamma transgene expression was selectively targeted to astrocytes, a potentially important cellular source of this cytokine. Here we report that astrocyte-directed expression of IFN-gamma results in regional hypomyelination and selective disruption of brain histogenesis, which included severe cerebellar and hippocampal dysplasia. Transgenic mice were markedly ataxic and the majority died prior to reaching sexual maturity. This study demonstrates that astrocyte-directed expression of IFN-gamma profoundly affects the differentiation and morphogenesis of the brain and provides additional evidence that this cytokine has deleterious consequences on myelin-producing cells, independent of the cellular source.

Herpes simplex virus infections and Alzheimer's disease. Implications for drug treatment and immunotherapy.

Interest in the possible role of herpes simplex virus type 1 (HSV1) as a cofactor in the pathogenesis of Alzheimer's disease (AD) has re-emerged following the detection of viral DNA sequences in the central nervous system (CNS). Evidence from 2 independent laboratories indicates that HSV1 may interact with a host-specific factor, the apolipoprotein E epsilon 4 allele, to further augment the risk for AD. In this review, we consider the arguments implicating HSV1 in the pathogenesis of AD. Although further studies are required to confirm a role for HSV1 in AD and to elucidate its underlying molecular basis, implicating a virus in the pathogenesis of this insidious disease clearly offers novel potential treatments.

Weaning ages in a sample of American women who practice extended breastfeeding.

This research examined age and method of weaning in a sample of 179 women who practiced extended breastfeeding. The average age for weaning was between 2 years 6 months and 3 years 0 months and ranged from 1 month to 7 years 4 months. Fourteen women had each weaned at least three children, and the youngest children were significantly older at the time of weaning than were their older siblings. Weaning was described as being "gradual" and "child-led" by the majority of women. A smaller, but substantial, percentage of women cited reasons for weaning related to a subsequent pregnancy. Weaning ages for women who practice extended nursing were substantially older than were those of more typical North American mothers and were similar to those in traditional cultures with similar parenting practices.

The social consequences of long-term breastfeeding.

This study examined the social consequences for mothers of long-term breastfeeding in a non-supportive culture, and how mothers learned to cope with negative reactions and comments from others. One hundred seventy-nine women who were recruited from La Leche League area conferences nationwide from 1989 to 1991 completed a self-administered closed-ended questionnaire which asked about their breastfeeding and weaning experiences. The percentage of mothers who cited "social stigma" as a negative aspect of breastfeeding increased dramatically as the age of the child increased; 29 percent cited social stigma for breastfeeding past six months, 44 percent for breastfeeding past 12 months, and 61 percent for breastfeeding past 24 months. In spite of the social stigma, the women cited more positive aspects for breastfeeding (M = 6.18 aspects) than they did negative aspects (M = .85 aspects). The positive aspects of breastfeeding emphasized the strong emotional bond between mother and child, and the emotional benefits they both received. Mother-to-mother support, spousal support, and a woman's own sense of confidence were important buffers against the criticism of others. And while the criticism of others was likely to cause negative feelings, the mothers reported that it had very little impact on their breastfeeding behaviors.

Right ventricular metastatic melanoma 27 years after resection of the primary tumor.

This article is a case report of a 65-year-old white woman with a history of malignant melanoma, resected from her back in 1959. She presented 27 years later with right-sided heart failure and metastatic melanoma to her right ventricle. To the authors' knowledge, a large ventricular mass as the sole site of disease recurrence has not been described previously.

Experimental manipulation of speaking rate for studying temporal variability in children's speech.

Children's speech timing is often more variable than adults'. In the present study, two hypotheses that have been proposed to account for this observation are considered. One claims that children do not have neuromotor control capabilities comparable to adults. The other suggests that the greater variability is a statistical consequence of children's longer segment durations. These two hypotheses were examined by having children and adults speak at both faster and slower rates than normal. Within-group comparisons across different rates and between-group comparisons for similar durational values were made from spectrographic measurements. Results indicate that both statistical and neuromotor factors seem to contribute to the greater variability commonly observed in children's speech.

A multivariate analysis of clinicians' perceptions of supervisory effectiveness.

The study was designed to identify and structure supervisory behaviors that speech clinicians perceive as critical to the process of supervision. A total of 164 student clinicians in 37 Midwestern clinical facilities evaluated the behavior of 87 clinical supervisors. Factor analysis yielded two distinct dimensions, interpersonal and administrative factors, and indicated that eight variables contributed most significantly to the evaluative process. When the variables were regressed against the supervisors' overall effectiveness ratings, a three-variable prediction system resulted. "Respect for the student clinician" was the single most valid predictor of perceived supervisory effectiveness, followed by "confrontation" and "empathy" variables. Implications for training supervisors in interactive skills are discussed, along with recommendations for future research.

Paranatal influences on maternal-infant attachment.

This paper reviews recent literature relating to effects on mother-infant attachment of events during pregnancy, birth, and the post-partum period. It is suggested that, for the sake of the physical and emotional well-being of child and mother, medical and technological interventions be held to a minimum during this time. Recommendations are made for the restructuring of routine professional practice.

Precocious periodontitis: a clinical entity and a treatment responsibility.

This report has proposed that the term, periodontosis, be discarded and replaced with the term, precocious periodontitis. The literature review has shown that, although the exact causative agents are unknown, certain microbiological reactions do occur and the condition is a periodontitis. The term, precocious periodontitis, has been suggested because the disease entity differs from chronic periodontitis in some of its characteristic features and etiologic factors. Three important local etiologic factors are: (1) contact and eruption of the first molars, (2) occlusal traumatism, and (3) ineffective oral hygiene. The recent literature concerning possible hereditary characteristics, bacteriological findings, and immunological reactions has been cited. The reports presented showing successful results of therapy were selected to illustrate that this condition can have the same prognosis and response to therapy as other similarly involved cases of periodontitis as a clinical entity with a definitive treatment responsibilities.

Plant thorn synovitis.

Five children with an inflammatory monarthritis due to penetration of the joint by plant thorns are presented. The clinical presentation was that of a transient acute synovitis followed by a relatively asymptomatic period, and later by chronic arthritis often after the thorn injury was forgotten. Histopathology demonstrated a granulomatous synovitis. Polarized light microscopy facilitated identification of the plant tissue within the synovium. Conservative medical therapy was ineffective, but surgical excision of the affected synovium resulted in normal joint function. The differential diagnosis of monarthritis in children in extensive, and awareness of this condition is necessary to elicit a comprehensive history and to avoid delay in treatment.