Testing the oxidative stress hypothesis of aging in primate fibroblasts: is there a correlation between species longevity and cellular ROS production?

The present study was conducted to test predictions of the oxidative stress theory of aging assessing reactive oxygen species production and oxidative stress resistance in cultured fibroblasts from 13 primate species ranging in body size from 0.25 to 120 kg and in longevity from 20 to 90 years. We assessed both basal and stress-induced reactive oxygen species production in fibroblasts from five great apes (human, chimpanzee, bonobo, gorilla, and orangutan), four Old World monkeys (baboon, rhesus and crested black macaques, and patas monkey), three New World monkeys (common marmoset, red-bellied tamarin, and woolly monkey), and one lemur (ring-tailed lemur). Measurements of cellular MitoSox fluorescence, an indicator of mitochondrial superoxide (O2(·-)) generation, showed an inverse correlation between longevity and steady state or metabolic stress-induced mitochondrial O2(·-) production, but this correlation was lost when the effects of body mass were removed, and the data were analyzed using phylogenetically independent contrasts. Fibroblasts from longer-lived primate species also exhibited superior resistance to H(2)O(2)-induced apoptotic cell death than cells from shorter-living primates. After correction for body mass and lack of phylogenetic independence, this correlation, although still discernible, fell short of significance by regression analysis. Thus, increased longevity in this sample of primates is not causally associated with low cellular reactive oxygen species generation, but further studies are warranted to test the association between increased cellular resistance to oxidative stressor and primate longevity.

Candida albicans colonization of dental plaque in elderly dysphagic patients.

BACKGROUND: Dysphagia is a common disorder among the elderly population. As many as 50% of nursing home residents suffer from dysphagia. It is important to identify patients at increased risk for colonization of dental and denture plaque by pathogenic organisms in order to prevent associated disease. OBJECTIVES: To quantify the prevalence and evaluate the effect of dental and denture plaque colonization by Candida albicans in hospitalized elderly dysphagic patients as a complication of stroke, as well as the effect of systemic antimicrobial therapy on C. albicans colonization in these patients. METHODS: We evaluated dysphagia and antibiotic therapy as risk factors for dental and denture plaque colonization by C. albicans in elderly stroke rehabilitating patients with dysphagia, as compared to elderly non-dysphagic stroke and non-stroke rehabilitating patients on days 0, 7 and 14 following admission to the Fliman Geriatric Rehabilitation Hospital. RESULTS: The risk of C. albicans colonization of dental plaque was greater in dysphagic patients than in those without dysphagia on day 0 (50% vs. 21%, P = 0.076), day 7 (58 vs. 15.2%, P = 0.008) and day 14 (58 vs. 15.2%, P = 0.08). Similarly, patients on antibiotic therapy were at greater risk for C. albicans colonization of dental plaque on day 0 (56 vs. 11%, P = 0.002), day 7 (44 vs. 14.8%, P = 0.04) and day 14 (39 vs. 19%, P = 0.18). The risk of C. albicans colonization of denture plaque as opposed to dental plaques in non-dysphagic patients was significantly greater on day 0 (45.7 vs. 21.2%, P = 0.03), day 7 (51.4 vs. 15.1%, P = 0.0016) and day 14 (54.3 vs. 15.1%, P = 0.0007). Dysphagia did not increase the risk of denture plaque colonization by C. albicans. CONCLUSIONS: Both dysphagia and antibiotic therapy are risk factors for C. albicans colonization of dental plaque, and although dysphagia does not significantly increase colonization of denture plaque, denture wearers are at greater risk of such colonization.

Biosafety concerns for shared flow cytometry core facilities.

Many researchers who need flow cytometry for their projects have neither sufficient funds nor the work volume to justify the purchase of an analytic cytometer or cell sorter. In shared flow cytometry facilities, costs for instrument purchases, cytometer maintenance, and personnel are pooled to provide economic services for a multitude of users when they are required. Owing to the diverse nature of the samples that are submitted to core facilities, the biohazard potential of the samples can vary dramatically. For the safety of facility personnel and users, it is critical that information about hazards contained in the samples be transmitted to instrument operators before flow cytometry experiments are started. During 1999 the former Biosafety Committee of the International Society for Analytical Cytology formulated a framework biosafety questionnaire for shared facilities designed to request information about the hazard potential of experimental samples from investigators who wish to use the facility. In this report we review safety issues that are pertinent to flow cytometry core facilities by discussing the individual components of this biosafety questionnaire.