Daily fluctuations in occupation with and worry about COVID-19.

In the first week after the first COVID-19 patient was reported in the Netherlands, we conducted a pre-registered momentary assessment study (7 surveys per day, 50 participants, 7 days) to study the dynamic relationship between individuals' occupation with and worries about COVID-19 in daily life, and the moderating role of neuroticism in this relationship. At the group level, higher scores on occupation and worry co-occurred, and occupation predicted worry 1 h later, but not vice versa. There were substantial individual differences in the magnitudes and directions of the effects. For instance, occupation with COVID-19 was related to increases in worry for some but decreases in worry for others. Neuroticism did not predict any of these individual differences in the links between worry and occupation. This study suggests that it is important to go beyond group-level analyses and to account for individual differences in responses to COVID-19.

Docosahexaenoic Acid and Periodontitis in Adults: A Randomized Controlled Trial.

Periodontitis is a common chronic inflammatory disease initiated by bacteria, resulting in bone resorption, tooth loss, and systemic inflammation. Long-chain omega-3 fatty acids such as docosahexaenoic acid (DHA) reduce periodontitis in animals. We aimed to determine whether DHA supplementation with low-dose aspirin would reduce periodontitis in humans. We conducted a double-blind placebo-controlled parallel trial lasting 3 mo. Fifty-five adults with moderate periodontitis were randomized to 2,000 mg of DHA or identical soy/corn oil capsules. All participants received 81 mg of aspirin but received no other treatments. We analyzed the primary outcome of per-pocket change in pocket depth using mixed models among teeth with pocket depth ≥5 mm. Secondary outcomes assessed with generalized estimating equations included gingival index, plaque index, and bleeding on probing. Gingival crevicular fluid samples were analyzed for changes in high-sensitivity C-reactive protein (hsCRP) and interleukins 6 and 1ß (IL-6 and IL-1ß). Plasma was analyzed for changes in systemic inflammatory markers, including hsCRP. We confirmed adherence with erythrocyte fatty acid measurement. Forty-six participants completed the trial. While similar at baseline, the proportion of DHA in red blood cell plasma membranes increased from 3.6% ± 0.9% to 6.2% ± 1.6% in the intervention group but did not change among controls. DHA supplementation decreased mean pocket depth (-0.29 ± 0.13; p = .03) and gingival index (-0.26 ± 0.13; p = .04). Plaque index and bleeding on probing did not change. Significant adjusted differences were found between DHA and control for both gingival crevicular fluid hsCRP (-5.3 ng/mL, standard error [SE] = 2.4, p = .03) and IL-1ß (-20.1 pg/mL, SE = 8.2, p = .02) but not IL-6 (0.02 pg/mL, SE = 0.71, p = .98) or systemic hsCRP (-1.19 mg/L, SE = 0.90, p = .20). In this randomized controlled trial, aspirin-triggered DHA supplementation significantly improved periodontal outcomes in people with periodontitis, indicating its potential therapeutic efficacy (clinicaltrials.gov NCT01976806).

New approaches for isolation of previously uncultivated oral bacteria.

A significant number of microorganisms from the human oral cavity remain uncultivated. This is a major impediment to the study of human health since some of the uncultivated species may be involved in a variety of systemic diseases. We used a range of innovations previously developed to cultivate microorganisms from the human oral cavity, focusing on anaerobic species. These innovations include (i) in vivo cultivation to specifically enrich for species actively growing in the oral cavity (the "minitrap" method), (ii) single-cell long-term cultivation to minimize the effect of fast-growing microorganisms, and (iii) modifications of conventional enrichment techniques, using media that did not contain sugar, including glucose. To enable cultivation of obligate anaerobes, we maintained strict anaerobic conditions in most of our cultivation experiments. We report that, on a per cell basis, the most successful recovery was achieved using minitrap enrichment (11%), followed by single-cell cultivation (3%) and conventional plating (1%). Taxonomically, the richest collection was obtained using the single-cell cultivation method, followed by minitrap and conventional enrichment, comprising representatives of 13, 9, and 4 genera, respectively. Interestingly, no single species was isolated by all three methods, indicating method complementarity. An important result is the isolation and maintenance in pure culture of 10 strains previously only known by their molecular signatures, as well as representatives of what are likely to be three new microbial genera. We conclude that the ensemble of new methods we introduced will likely help close the gap between cultivated and uncultivated species from the human oral cavity.

Is obesity an oral bacterial disease?

The world-wide explosion of overweight people has been called an epidemic. The inflammatory nature of obesity is widely recognized. Could it really be an epidemic involving an infectious agent? In this climate of concern over the increasing prevalence of overweight conditions in our society, we focus on the possible role of oral bacteria as a potential direct contributor to obesity. To investigate this possibility, we measured salivary bacterial populations of overweight women. Saliva was collected from 313 women with a body mass index between 27 and 32, and bacterial populations were measured by DNA probe analysis. Levels in this group were compared with data from a population of 232 healthy individuals from periodontal disease studies. The median percentage difference of 7 of the 40 bacterial species measured was greater than 2% in the saliva of overweight women. Classification tree analysis of salivary microbiological composition revealed that 98.4% of the overweight women could be identified by the presence of a single bacterial species (Selenomonas noxia) at levels greater than 1.05% of the total salivary bacteria. Analysis of these data suggests that the composition of salivary bacteria changes in overweight women. It seems likely that these bacterial species could serve as biological indicators of a developing overweight condition. Of even greater interest, and the subject of future research, is the possibility that oral bacteria may participate in the pathology that leads to obesity.