IMMUNE REACTIONS IN PATIENTS WITH BLADDER AND PROSTATIC CANCER1

Although there are many reports of cellular immune reactions in bladder and prostatic carcinoma patients, few have demonstrated the presence of humoral reactivity. The use of microtechniques, especially the enzyme-linked immunosorbent assay (ELISA), has made sequential studies possible on patients with early or small tumours. Using this assay, the presence of serum antibodies has been demonstrated in both bladder and prostate patients, the specificities of these reactions being checked against a battery of different tumours and normal tissues. In many of the patients, with low or transient antibody levels, the presence of circulating immune complexes was shown by the Raji cell assay and analysed by double counter-current immunoelectrophoresis (DCIE). The content of these complexes appeared to be either antibody and tumour antigen or antibody and antiimmunoglobulin. In a small series of cryosurgically treated prostatic carcinoma patients, the course of these antibodies was monitored over several weeks, and the fluctuations in antibody levels were related to the presence of these different types of complexes.     

Energy expenditure of calorically restricted rats is higher than predicted from their altered body composition

Debate exists over the impact of caloric restriction (CR) on the level of energy expenditure. At the whole animal level, CR decreases metabolic rates but in parallel body mass also declines. The question arises whether the reduction in metabolism is greater, smaller or not different from the expectation based on body mass change alone. Answers to this question depend on how metabolic rate is normalized and it has recently been suggested that this issue can only be resolved through detailed morphological investigation. Added to this issue is the problem of how appropriate the resting energy expenditure is to characterize metabolic events relating to aging phenomena. We measured the daily energy demands of young and old rats under ad libitum (AD) food intake or 40% CR, using the doubly labeled water (DLW) method and made detailed morphological examination of individuals, including 21 different body components. Whole body energy demands of CR rats were lower than AD rats, but the extent of this difference was much less than expected from the degree of caloric restriction, consistent with other studies using the DLW method on CR animals. Using multiple regression and multivariate data reduction methods we built two empirical predictive models of the association between daily energy demands and body composition using the ad lib animals. We then predicted the expected energy expenditures of the CR animals based on their altered morphology and compared these predictions to the observed daily energy demands. Independent of how we constructed the prediction, young and old rats under CR expended 30 and 50% more energy, respectively, than the prediction from their altered body composition. This effect is consistent with recent intra-specific observations of positive associations between energy metabolism and lifespan and theoretical ideas about mechanisms underpinning the relationship between oxygen consumption and reactive oxygen species production in mitochondria.     

Life events and hemodynamic stress reactivity in the middle-aged and elderly

Recent versions of the reactivity hypothesis, which consider it to be the product of stress exposure and exaggerated hemodynamic reactions to stress that confers cardiovascular disease risk, assume that reactivity is independent of the experience of stressful life events. This assumption was tested in two substantial cohorts, one middle-aged and one elderly. Participants had to indicate from a list of major stressful life events up to six they had experienced in the previous 2 years. They were also asked to rate how disruptive and stressful they were, at the time of occurrence and now. Blood pressure and pulse rate were measured at rest and in response to acute mental stress. Those who rated the events as highly disruptive at the time of exposure and now exhibited blunted systolic blood pressure reactions to acute stress. The present results suggest that acute stress reactivity may not be independent of stressful life events experience.     

Neuroticism, cortisol reactivity, and antibody response to vaccination

This study examined whether neuroticism was related to the antibody response to influenza vaccination and whether the relationship was mediated by cortisol reactions to acute laboratory mental stress. Antibody status was assessed at baseline and to a trivalent influenza vaccination in 57 students at 5-week and 5-month follow-up. Neuroticism was also measured at baseline. Cortisol was measured at rest and in response to a pressurized mental arithmetic task. At both follow-ups, higher neuroticism scores were associated with poorer A/Panama antibody response, following adjustment for baseline antibody titer. Higher neuroticism scores were also associated with blunted cortisol reactivity, and blunted cortisol reactivity was associated with poorer A/Panama antibody response, but only at 5 months. However, there was no conclusive evidence that cortisol reactivity mediated the association between neuroticism and antibody response.