Histopathologic brain age estimation via multiple instance learning.

Understanding age acceleration, the discordance between biological and chronological age, in the brain can reveal mechanistic insights into normal physiology as well as elucidate pathological determinants of age-related functional decline and identify early disease changes in the context of Alzheimer's and other disorders. Histopathological whole slide images provide a wealth of pathologic data on the cellular level that can be leveraged to build deep learning models to assess age acceleration. Here, we used a collection of digitized human post-mortem hippocampal sections to develop a histological brain age estimation model. Our model predicted brain age within a mean absolute error of 5.45 ± 0.22 years, with attention weights corresponding to neuroanatomical regions vulnerable to age-related changes. We found that histopathologic brain age acceleration had significant associations with clinical and pathologic outcomes that were not found with epigenetic based measures. Our results indicate that histopathologic brain age is a powerful, independent metric for understanding factors that contribute to brain aging.

Self-esteem, self-serving cognitions, and health risk behavior.

The current article reviews prospective and experimental research on the relation between self-esteem and perceptions of vulnerability. These studies demonstrate that individuals with high self-esteem who engage in risk behavior often utilize a variety of self-serving cognitive strategies that protect them from fully acknowledging their vulnerability to the potential negative consequences of their behavior; e.g., they minimize their estimates of personal risk and overestimate the prevalence of the risk behavior among their peers. The article also provides data on an additional self-serving cognitive strategy employed by adolescents with high self-esteem--alteration of perceptions of others' reactions to their own risk behavior. Finally, the article reviews the emerging literature on the relation between these cognitive strategies and maladaptive health behavior, and proposes that whether these strategies are maladaptive depends on the nature of the threat and the availability of opportunities to engage in compensatory self-enhancement.

Use of simple and complex in vitro models for multiparameter characterization of human blood-material/device interactions.

Medical devices, intended for blood contacting applications, undergo extensive in vitro testing followed by animal and clinical feasibility studies. Besides the use of materials known to be intrinsically blood-compatible, the surface of such devices is often modified with a coating in order to improve the performance characteristics during blood exposure. In vitro evaluation of blood-device interactions accompanies the product development cycle from the early design phase using basic material geometries until final finished-product testing. Specific test strategies can vary significantly depending on the end application, the particular study objectives and variables of interest, and cost. To examine the degree to which findings derived from two different in vitro approaches complement one another, this report contrasts findings from a simple multipass loop model with findings from a simulated cardiopulmonary bypass (CPB) model. The loop model consists of tubular test materials, with and without surface modification, formed into valved Chandler loops. The CPB model has an oxygenator with and without surface modification connected to a reservoir and a blood pump. The surface modifications studied in this report are the Carmeda BioActive Surface and Duraflo II heparin coatings. Common blood parameters in the categories of coagulation, platelets, hematology, and immunology were monitored in each model. Ideal models employ the optimal level of complexity to study the design variables of interest and to meet practical cost considerations. In the case of medical device design studies, such models should also be predictive of performance. In the more complex and realistic simulated CPB model, experimental design and cost factors prevented easy/optimum manipulation of critical variables such as blood donor (use of paired samples) and heparin level. Testing in the simpler loop model, on the other hand, readily offered manipulation of these variables, and produced findings which overlapped with observations from the more complex CPB model. Thus, the models described here complimented one another. Moreover, conclusions from consistent findings, such as favorable responses associated with the heparin coatings, between the two models were considered to be more robust.

The effect of peers' alcohol consumption on parental influence: a cognitive mediational model.

OBJECTIVE: The current study was designed to elucidate familial and social influences on adolescent alcohol consumption by testing three hypotheses derived from the prototype/willingness model of adolescent risk behavior: (1) parents' prototypes of adolescent drinkers affect adolescent consumption through their impact on adolescents' prototypes, (2) strong parent-child relationships are associated with acceptance of parental influence regarding drinking and thus with less adolescent drinking and (3) association with peers who drink dilutes parental influence over adolescents' alcohol consumption. METHOD: Two hundred sixty-six rural adolescents, ages 15 through 17 at Time 1, and their parents and siblings completed questionnaires about drinking behavior and drinking-related cognitions at 1-year intervals for 3 years. RESULTS: Structural equation models provided evidence of transmission of prototypes of adolescent drinkers from parents to adolescents and evidence that these prototypes mediate adolescent alcohol consumption. They also provide evidence that although parents' prototypes and parent-adolescent relationships are important in shaping the adolescents' drinking, association with peers who drink significantly attenuates this influence. CONCLUSIONS: These data suggest that parents can influence their children's drinking, but that this influence has more of an impact if the adolescent is not involved in a drinking-conducive peer environment. The current analyses also suggest that the process of becoming an adolescent drinker involves an active rejection of parents' influence rather than a passive movement away from parents' attitudes and beliefs-a process that is accelerated by association with peers who drink.

The effect of risk communication on risk perceptions: the significance of individual differences.

The purpose of this paper is to address the literature on the relation between risk communication and the initiation of health behavior change. More specifically, we examine the evidence that providing risk information is an effective way to change risk perceptions, as well as the more limited evidence that altering risk perceptions influences risk behavior. The paper discusses significant developments in the research on these issues, describes specific studies that represent trends in this research, and discusses methodologic issues important to the development of the field. Although there are relatively few studies that demonstrate causal links between risk communication and behavior change, recent developments in the field point to the importance of tailoring risk communications to the individual characteristics of targets. Such tailoring has taken a variety of forms, including providing individualized feedback concerning risk status or genetic vulnerability and assessing readiness for behavior change. Future intervention efforts should combine individualized risk status feedback with assessment of individual differences in previous behavior and acceptance of personal vulnerability.