Remediating office environments of spore-forming bacteria.

This study examines decontamination processes that were developed on an emergency basis to eliminate Bacillus anthracis spores from deliberately contaminated buildings. The recommended steps include a survey with sampling, the removal of sensitive items, and HEPA vacuuming of all readily available surfaces, followed by biocide treatment and subsequent analyses for viable cells. There are several analytical challenges posed by this approach. These include the ability to discriminate the added strain from naturally occurring resident microbes, determining detection limits for anthrax spores in settled dusts, and detecting viable but nonculturable spores. There are also logistical issues relating to the various skill sets required from investigation to reconstruction. In the present study, a model office was constructed, and a strain of Bacillus pumilus was isolated from the carpet and reintroduced to the office in excess. The abundance of the B. pumilus strain was monitored in settled dust using a strain-specific, quantitative polymerase chain reaction (QPCR)-based detection method following repeated HEPA vacuum cleanings. The QPCR method had a limit of detection corresponding to < or = 10(2) colony forming units per gram of settled dust. QPCR results were compared with measures of dust recoveries and fungal glucan and endotoxin levels in the dust samples. The largest fraction (ca. 81%) of added spores was recovered during the first HEPA cleaning. Subsequent cleanings resulted in incrementally lower recoveries, with removal of 93% of the initial inoculum by the third HEPA vacuuming. HEPA vacuuming prior to removal of items such as office contents and furnishings would result in much less resuspension of dust and limiting the extent of contamination. This approach also ensures that residual contaminants are as low as can be reasonably achieved.

Are cell phones an indicator of personal exposure to organophosphate flame retardants and plasticizers?

BACKGROUND: Exposure to organophosphate ester (OPE) flame retardants and plasticizers is widespread and is of concern due to their toxicity. OBJECTIVES: To investigate relationships between and within OPE concentrations in air, dust, hands, electronic product wipes and urinary metabolites with the goal of identifying product sources and exposure pathways. METHODS: Women in Toronto and Ottawa, Canada, provided a urine sample, two sets of hand wipes, access to their homes for air and dust sampling, and completed a questionnaire. OPE concentrations were obtained for air and floor dust in the bedroom (n = 51) and most used room (n = 26), hand wipes (n = 204), and surface wipes of handheld (n = 74) and non-handheld electronic devices (n = 125). All air, dust and wipe samples were analyzed for 23 OPE compounds; urine samples (n = 44) were analyzed for 8 OPE metabolites. RESULTS: Five-8 OPEs were detected in >80% of samples depending on the sample type. OPE median concentrations in hand wipes taken 3 weeks apart were not significantly different. Palms had higher concentrations than the back of hands; both were significantly correlated. Concentrations of 9 OPEs were significantly higher in surface wipes of handheld than non-handheld electronic devices. Six OPEs in hand wipes were significantly correlated with cell phone wipes, with two to four OPEs significantly correlated with tablet, laptop and television wipes. Multiple regression models using hand wipes, cell phone wipes and dust explained 8-33% of the variation in creatinine-adjusted urinary metabolites; air concentrations did not have explanatory power. OPEs in cell phone wipes explained the greatest variation in urinary metabolites. CONCLUSIONS: Handheld electronic devices, notably cell phones, may either be sources or indicators of OPE exposure through hand-to-mouth and/or dermal uptake.

Characterization of active site variants of xanthine hydroxylase from Aspergillus nidulans.

Xanthine/alpha-ketoglutarate (alphaKG) dioxygenase (XanA) is a non-heme mononuclear Fe(II) enzyme that decarboxylates alphaKG to succinate and CO(2) while hydroxylating xanthine to generate uric acid. In the absence of a XanA crystal structure, a homology model was used to target several putative active site residues for mutagenesis. Wild-type XanA and ten enzyme variants were purified from recombinant Escherichia coli cells and characterized. The H149A and D151A variants were inactive and the H340A variant exhibited only 0.17% of the wild-type enzyme activity, consistent with the proposed role of His149, Asp151, and His340 as Fe ligands. The K122A variant led to a 2-fold increase in the K(d) of alphaKG as measured by fluorescence quenching analysis, in agreement with Lys122 acting to stabilize the binding of alphaKG. The N358A variant exhibited a 23-fold decrease in k(cat)/K(m) compared to wild-type XanA, pointing to a key role of Asn358 in catalysis. 9-Methylxanthine was exploited as an alternate substrate, and the C357A, E137A, and D138A variants were found to exhibit relatively enhanced activity consistent with Cys357, Glu137, and Asp138 being proximal to N-9 or involved in its proper positioning. 6,8-Dihydroxypurine was identified as a slow-binding competitive inhibitor of XanA, and significant decreases (E137A and D138A) or increases (Q356A and N358A) in K(i)(app) of the variants were interpreted in terms of distinct interactions between this compound and the corresponding active site side chains. Further support for Cys357 residing at the active site was obtained using thiol-specific reagents that inactivated wild-type enzyme (with partial protection by substrate), whereas the C357A variant was resistant to these reagents. The Q101A, Q356A, and C357A variants showed elevated ferroxidase activity in the absence of substrates, pointing to the presence of the corresponding side chains at the active site. These results confirm most aspects of the homology model and provide additional insight into the enzyme reactivity.

Improving bedside teaching: findings from a focus group study of learners.

PURPOSE: Literature reviews indicate that the proportion of clinical educational time devoted to bedside teaching ranges from 8% to 19%. Previous studies regarding this paucity have not adequately examined the perspectives of learners. The authors explored learners' attitudes toward bedside teaching, perceptions of barriers, and strategies to increase its frequency and effectiveness, as well as whether learners' stages of training influenced their perspectives. METHOD: Six focus group discussions with fourth-year medical students and first- or second-year internal medicine residents recruited from the Boston University School of Medicine and Residency Program in Internal Medicine were conducted between June 2004 and February 2005. Each 60- to 90-minute discussion was audiotaped, transcribed, and analyzed using qualitative methods. RESULTS: Learners believed that bedside teaching is valuable for learning essential clinical skills. They believed it is underutilized and described many barriers to its use: lack of respect for the patient; time constraints; learner autonomy; faculty attitude, knowledge, and skill; and overreliance on technology. Learners suggested a variety of strategies to mitigate barriers: orienting and including the patient; addressing time constraints through flexibility, selectivity, and integration with work; providing learners with reassurance, reinforcing their autonomy, and incorporating them into the teaching process; faculty development; and advocating evidence-based physical diagnosis. Students focused on the physical diagnosis aspects of bedside teaching, whereas views of residents reflected their multifaceted roles as learners, teachers, and managers. CONCLUSIONS: Bedside teaching is valuable but underutilized. Including the patient, collaborating with learners, faculty development, and promoting a supportive institutional culture can redress several barriers to bedside teaching.

The influence of three e-cigarette models on indoor fine and ultrafine particulate matter concentrations under real-world conditions.

Electronic cigarette (e-cigarette) use has steadily increased since 2010. Indoor e-cigarette use exposes bystanders to a new source of particulate matter (PM) air pollution. Elevated short-term exposures to PM with a lower measuremented aerodynamic diameter (≤2.5 µm), PM2.5 and ultrafine particles (UFPs) have been linked to increased risk of adverse respiratory and cardiac events. This exposure study estimated concentrations of PM2.5 and UFPs from indoor e-cigarette use at 0.5 meters (m) and 1 m away from an e-cigarette user and investigated whether these indoor concentrations varied across three common e-cigarette models. One e-cigarette user tested three different e-cigarettes containing the same nicotine solution on three separate occasions and measured concentrations on PM2.5 and UFPs at 0.5 and 1 m in a ∼38 m3 office. Continuous measures of PM2.5 and UFPs were taken for 5.5 min before e-cigarette use, then the user puffed seven times for 6.5 min (exposure), and for 10 min after ceasing e-cigarette use. Following the initiation of e-cigarette use, levels of PM2.5 increased 160-fold at a distance of 0.5 m, and 103-fold at 1 m. The corresponding increases in UFP counts were 5.2, and 3.0-fold higher, respectively. The PM2.5 concentrations and UFP counts between e-cigarette models were statistically significantly different at 1 m, but not at 0.5 m. There was substantial variability between distances, e-cigarettes, and replicates. This study indicates that e-cigarette vapors influence PM2.5 and UFPs concentrations/counts at close proximity distances indoors; additional research is needed to characterize the composition of those particles and evaluate the impacts of other e-cigarette solutions on indoor air quality.

The path to physician leadership in community health centers: implications for training.

BACKGROUND AND OBJECTIVES: Community health centers are facing a shortage of primary care physicians at a time when government plans have called for an expansion of community health center programs. To succeed with this expansion, community health centers require additional well-trained physician leadership. Our objective was to ascertain how medical directors obtain leadership skills in an attempt to identify the best methods and venues for providing future leadership training programs. METHODS: Using recorded interviews and focus group data with community health center medical directors, we identified patterns and themes through cross-case content analysis to determine leadership training needs in underserved settings. RESULTS: Medical directors often enter positions unprepared and can quickly become frustrated by an inability to make system improvements. Medical directors seek multiple ways to obtain the leadership skills necessary, including conferences, peer networking, mentorship, and formal degree training. Many directors express a desire for additional training, preferring flexibility in curriculum and hands-on components. CONCLUSIONS: Additional leadership training opportunities for active and future medical directors are needed. Academic medical centers and other training sponsors should consider innovative ways to develop effective physician leadership to provide quality care to underserved communities.

Probing and overcoming a mould menace.

Thorough investigation of an environmental problem within Brockville General Hospital, Ontario, Canada, was vital. This special report is by William Roth, Chris Rahm and Bruce G. Fraser--all of Jacques Whitford Environment Limited. William Roth is the first point of contact for Jacques Whitford's hospital clients and is a project manager within the Environmental Engineering group of JWEL's Ottawa office. Chris Rahm is a member of the Hazardous Materials group in JWEL's Ottawa office and was the site supervisor for the mould abatement at BGH. Bruce Fraser is the corporate technical director of indoor air quality for JWEL and regularly provides technical assistance for mould related projects carried out by JWEL.