Cellular and humoral immunity to rat hepatoma-specific antigens correlated with tumour status

Lymphocytes from rats bearing primary or transplanted aminoazo-dye-induced hepatomas were specifically cytotoxic for cells of the same tumour. Cytotoxic antibody was not present in the serum of these animals, although humoral factors capable of abrogating lymph-node cell-mediated cytotoxicity in vitro were detected. Following excision of transplanted hepatomas, cytotoxic lymph-node cells were still demonstrable, with slightly increased reactivities comparable to those detected in a previous study of repeatedly immunized rats. Cytotoxic antibody was present in serum after tumour excision, and this correlates with the loss of serum blocking activity for lymph-node cell-mediated cytotoxic effects. In comparison, serum from rats repeatedly immunized to hepatomas, where high levels of cytotoxic antibody are also present, blocks lymph-node cell-mediated reactions in vitro, despite the immune status of the donor. These considerations suggest qualitative differences between the blocking factors in the serum of tumour-bearer and tumour-immune hosts, the former being antigen-antibody complexes, and the latter free antibody.     

Memory retention--the synaptic stability versus plasticity dilemma

Memory maintenance is widely believed to involve long-term retention of the synaptic weights that are set within relevant neural circuits during learning. However, despite recent exciting technical advances, it has not yet proved possible to confirm experimentally this intuitively appealing hypothesis. Artificial neural networks offer an alternative methodology as they permit continuous monitoring of individual connection weights during learning and retention. In such models, ongoing alterations in connection weights are required if a network is to retain previously stored material while learning new information. Thus, the duration of synaptic change does not necessarily define the persistence of a memory; rather, it is likely that a regulated balance of synaptic stability and synaptic plasticity is required for optimal memory retention in real neuronal circuits.     

Beyond the justification hypothesis: a broader theory of the evolution of self-consciousness

We evaluate Henriques' Justification Hypothesis (JH; this issue) and argue that his explanation for the evolution of self-consciousness is overly narrow and the evolutionary sequence of events is backwards. Instead, we propose a broader theory of the evolution of self-consciousness, with four categories of adaptive functions: (a) self-regulation, (b) selective information processing, (c) understanding others, and (d) identity formation.     

Identification of gaps in the diagnosis and treatment of childhood asthma using a community-based participatory research approach

The goal of this investigation was to use a community-based participatory research approach to develop, pilot test, and administer an asthma screening questionnaire to identify children with asthma and asthma symptoms in a community setting. This study was conducted as the recruitment effort for Community Action Against Asthma, a randomized trial of a household intervention to reduce exposure to environmental triggers of asthma and was not designed as a classic prevalence study. An asthma screening questionnaire was mailed and/or hand delivered to parents of 9,627 children, aged 5 to 11 years, in two geographic areas of Detroit, Michigan, with predominantly African American and Hispanic populations. Additional questionnaires were distributed via community networking. Measurements included parent report of their child's frequency of respiratory symptoms, presence of physician diagnosis of asthma, and frequency of doctor-prescribed asthma medication usage. Among the 3,067 completed questionnaires, 1,570 (51.2% of returned surveys, 16.3% of eligible population) were consistent with asthma of any severity and 398 (12.9% of returned surveys, 4.1% of eligible population) met criteria, for moderate-to-severe asthma. Among those meeting criteria for moderate-to-severe asthma, over 30% had not been diagnosed by a physician, over one half were not taking daily asthma medication, and one quarter had not taken any physician-prescribed asthma medication in the past year. Screening surveys conducted within the context of a community-based participatory research partnership can identify large numbers of children with undiagnosed and/or undertreated moderate-to-severe asthma. These children are likely to benefit from interventions to reduce morbidity and improve quality of life.     

Integrating genetics as practices of primary care

This study examines the responses of general practitioners (GPs) in Vic., Australia to an increased emphasis on genetics in primary care. A qualitative analysis of focus group interviews with GPs in regional and metropolitan areas and one focus group interview with genetics experts showed that despite the emphasis placed on genetics by the experts, GPs remained ambivalent to the routine integration of genetics into general practice. This response from GPs has been noted in several studies and is most commonly attributed to GPs' lack of knowledge about genetics. In this study we argue that a 'cognitive deficit' understanding of the problem excludes many of the factors that GPs regard as important in relating genetics to primary care. We show that GPs' ambivalence emerges from how they situate genetics within practices of patient care and in relation to what they regard as good patient management. We found that GPs respond most enthusiastically to genetics and genetic testing if they feel it changes their management in ways they consider of benefit to their patients. GPs have specialist skills in managing the heterogeneity of patient care and these skills enable them to situate genetics relative to the overall needs of patients. Preparing GPs to 'do' genetics when the need arises by finding ways to make genetics information available to them as the need arises would facilitate the integration of genetics as practices of primary care.