Chronic and pulse exposure effects of silver nanoparticles on natural lake phytoplankton and zooplankton

The increasing use of silver nanoparticles (AgNPs) in consumer products raises concerns regarding the environmental exposure and impact of AgNPs on natural aquatic environments. Here, we investigated the effects of environmentally relevant AgNP concentrations on the natural plankton communities using in situ enclosures. Using twelve lake enclosures, we tested the hypotheses that AgNP concentration, dosing regimen, and capping agent (poly-vinyl pyrrolidone (PVP) vs. citrate) exhibit differential effects on plankton communities. Each of the following six treatments was replicated twice: control (no AgNPs added), low, medium, and high chronic PVP treatments (PVP-capped AgNPs added continuously, with target nominal concentrations of 4, 16, and 64?μg/L, respectively), citrate treatment (citrate-capped AgNPs added continuously, target nominal concentrations of 64?μg/L), and pulse treatment (64?μg/L PVP-AgNPs added as a single dose). Although Ag accumulated in the phytoplankton, no statistically significant treatment effect was found on phytoplankton community structure or biomass. In contrast, as AgNP exposure rate increased, zooplankton abundance generally increased while biomass and species richness declined. We also observed a shift in the size structure of zooplankton communities in the chronic AgNP treatments. In the pulse treatments, zooplankton abundance and biomass were reduced suggesting short periods of high AgNP concentrations affect zooplankton communities differently than chronic exposures. We found no evidence that capping agent affected AgNP toxicity on either community. Overall, our study demonstrates variable AgNP toxicity between trophic levels with stronger AgNP effects on zooplankton. Such effects on zooplankton are troubling and indicate that AgNP contamination could affect aquatic food webs.     

Is two days of intermittent energy restriction per week a feasible weight loss approach in obese males? A randomised pilot study

Aim

The 5:2 diet (two non‐consecutive days of 2460 KJ (600 calories) and 5 days of ad libitum eating per week) is becoming increasingly popular. This pilot study aimed to determine whether the 5:2 diet can achieve ≥5% weight loss and greater improvements in weight and biochemical markers than a standard energy‐restricted diet (SERD) in obese male war veterans.

Methods

A total of 24 participants were randomised to consume either the 5:2 diet or a SERD (2050 KJ (500 calorie) reduction per day) for 6 months. Weight, waist circumference (WC), fasting blood glucose, blood lipids, blood pressure and dietary intake were measured at baseline, 3 and 6 months by a blinded investigator.

Results

After 6 months, participants in both groups significantly reduced body weight (P = <0.001), WC (P = <0.001) and systolic blood pressure (P = 0.001). Mean weight loss was 5.3 ± 3.0 kg (5.5 ± 3.2%) for the 5:2 group and 5.5 ± 4.3 kg (5.4 ± 4.2%) for the SERD group. Mean WC reduction for the 5:2 group was 8.0 ± 4.5 and 6.4 ± 5.8 cm for the SERD group. There was no significant difference in the amount of weight loss or WC reduction between diet groups. There was no significant change in diastolic blood pressure, fasting blood glucose or blood lipids in either dietary group.

Conclusions

Results suggest that the 5:2 diet is a successful but not superior weight loss approach in male war veterans when compared to a SERD. Future research is needed to determine the long‐term effectiveness of the 5:2 diet and its effectiveness in other population groups.     

How many problems do family physicians manage at each encounter? A WReN study

PURPOSE: The number of problems managed concurrently by family physicians during patient encounters has not been fully explored despite the implications for quality assessment, guideline implementation, education, research, administration, and funding. Our study objective was to determine the number of problems physicians report managing at each visit and compare that with the number reflected in the chart and the bill. METHODS: Twenty-nine members of the Wisconsin Research Network reported on encounters with 572 patients using a physician problem log. The patient chart notes and the diagnoses submitted for billing from the encounters were compared with the information in these logs. RESULTS: The physicians reported managing an average of 3.05 problems per encounter and recorded 2.82 in the chart and 1.97 on the bill. For all patients, 37% of encounters addressed more than 3 problems, and 18% addressed more than 4. For patients older than 65 years, there was an average of 3.88 problems at each visit, and for diabetic patients there was an average of 4.60. There was evidence for the selective omission of mental health and substance problems from the diagnoses used for billing. CONCLUSIONS: Family medicine involves the concurrent care of multiple problems, which billing data do not adequately reflect. Our findings suggest a mismatch between family medicine and current approaches to quality assessment, guideline implementation, education, research, administration, and funding. Activities in all these areas need to address the physician's task of prioritizing and integrating care for multiple problems concurrently.     

Insurance coverage of smoking cessation treatment for state employees

Public health experts recommend that health insurance include coverage for smoking cessation treatment as an evidence-based strategy to reduce smoking. As employers, states can implement this policy for more than 5 million individuals nationwide. This study identified the extent to which states require smoking cessation treatment insurance coverage for their employees; of 45 states, 29 required coverage for at least 1 US Public Health Service (PHS)-recommended treatment, and only 17 of 45 provided coverage that was fully consistent with PHS recommendations.     

Mycoplasma bovis Infections in Free-Ranging Pronghorn,Wyoming, USA

Mycoplasma bovis is 1 of several bacterial pathogens associated with pneumonia in cattle. Its role in pneumonia of free-ranging ungulates has not been established. Over a 3-month period in early 2019, »60 free-ranging pronghorn with signs of respiratory disease died in northeast Wyoming, USA. A consistent finding in submitted carcasses was severe fibrinosuppurative pleuropneumonia and detection of M. bovis by PCR and immunohistochemical analysis. Multilocus sequence typing of isolates from 4 animals revealed that all have a deletion in 1 of the target genes, adh-1. A retrospective survey by PCR and immunohistochemical analysis of paraffin-embedded lung from 20 pronghorn that died with and without pneumonia during 2007–2018 yielded negative results. These findings indicate that a distinct strain of M. bovis was associated with fatal pneumonia in this group of pronghorn.     

Antimicrobial resistance and molecular characterization of Vibrio cholerae O1 during the 2004 and 2005 outbreak of cholera in Cameroon

There was an outbreak of cholera in Cameroon during 2004 and 2005; the epidemic began in Douala in January 2004 and spread throughout the south of the country. The World Health Organization (WHO) reported 8005 cases in 2004 and 2847 cases in 2005. Five hundred eighty-nine stool samples were received in the Pasteur Centre of Cameroon and 352 were microbiologically confirmed to be positive for Vibrio cholerae O1. Isolated strains were tested for their antimicrobial susceptibilities. All the strains were multidrug resistant and predominantly showed a common resistance pattern at the beginning of the outbreak. Tetracycline, recommended by the WHO for treating cholera in adults, was effective against all the strains tested. Cotrimoxazole (trimethoprim/sulfamethoxazole), previously a first-line treatment in children, was ineffective in vitro for all the clinical isolates and was quickly replaced by amoxicillin. Ampicillin resistance emerged at the end of 2004 and was the leading resistance pattern observed in the second half of 2005. This therefore represented the second major resistance pattern. These two major resistance profiles were not associated with patient characteristics (sex and age) or to the geographic origin of strains. However, there was a highly significant relationship between resistance patterns and the year of isolation (p < 0.001). The strains possessed genes ctxA and ctxB encoding the two cholera toxin subunits and were very closely related, irrespective of their antimicrobial resistance patterns. They were not differentiated by molecular typing methods and gave similar ribotyping and pulsed-field gel electrophoresis patterns.     

The relationship of stress and coping methods to adolescent marijuana use

As the use of marijuana among adolescents remains high, more effective interventions are needed. We conducted this cross‐sectional survey at an outpatient, university‐based, adolescent clinic to determine the prevalence of marijuana use in an inner‐city adolescent population and to examine the relationship of stress and coping methods to marijuana user status (never user, experimenter, and frequent user). The subjects were 918 adolescents aged 12–21 years. Lifetime use in this population was 59% (n = 611) with 18.4% (n = 191) reporting frequent weekly use. Almost all (97%) marijuana users acknowledged marijuana use by friends. Stepwise logistic regression analysis showed that negative life events, greater use of the negative coping method of anger and less frequent use of the positive coping method of parental support were significantly and independently related to marijuana user status. In the presence of high peer use, exploring parent‐child relationships and use of anger coping and intervening accordingly may decrease marijuana use.     

Toxicity of Silver and Titanium Dioxide Nanoparticle Suspensions to the Aquatic Invertebrate, Daphnia magna

The purpose of this study was to investigate the 48 h acute toxicity of capped silver nanoparticles (AgNPs), and capped and uncapped titanium dioxide (nTiO₂) to Daphnia magna neonates. In addition, a 24 days chronic toxicity study was performed for D. magna exposed to uncapped nTiO₂ to evaluate effects on growth, reproduction and survival. The 48 h median lethal concentrations (LC₅₀) for carboxy-functionalized capped AgNPs and uncapped nTiO₂ were 2.75 μg/L and 7.75 mg/L, respectively. In contrast, no mortalities were observed for Daphnia exposed to carboxy-functionalized capped nTiO₂ at concentrations up to 30 mg/L. In the chronic toxicity experiment with uncapped nTiO₂, the growth, reproduction and survival of D. magna were significantly (p < 0.05) reduced at concentrations ranging from 4.5 to 7.5 mg/L. Growth and reproduction were reduced by 35 % and 93 %, respectively in the treatments at the highest uncapped nTiO₂ concentration (7.5 mg/L). Time to first reproduction was delayed by 2–3 days in D. magna and the test organisms produced only 1–2 broods over 24 days exposure to the highest concentration of uncapped nTiO₂. Overall, the results from the present study indicate that exposures of aquatic invertebrates to nanoparticles could have important ecological effects on lower trophic levels in aquatic ecosystems.     

Strengthening capacity in developing countries for evidence-based public health: the data for decision-making project

Public health officials and the communities they serve need to: identify priority health problems; formulate effective health policies; respond to public health emergencies; select, implement, and evaluate cost-effective interventions to prevent and control disease and injury; and allocate human and financial resources. Despite agreement that rational, data-based decisions will lead to improved health outcomes, many public health decisions appear to be made intuitively or politically. During 1991-1996, the US Centers for Disease Control and Prevention implemented the US Agency for International Development funded Data for Decision-Making (DDM) Project. DDM goals were to: (a) strengthen the capacity of decision makers to identify data needs for solving problems and to interpret and use data appropriately for public health decisions; (b) enhance the capacity of technical advisors to provide valid, essential, and timely data to decision makers clearly and effectively; and (c) strengthen health information systems (HISs) to facilitate the collection, analysis, reporting, presentation, and use of data at local, district, regional, and national levels. Assessments were conducted to identify important health problems, problem-driven implementation plans with data-based solutions as objectives were developed, interdisciplinary, in-service training programs for mid-level policy makers, program managers, and technical advisors in applied epidemiology, management and leadership, communications, economic evaluation, and HISs were designed and implemented, national staff were trained in the refinement of HISs to improve access to essential data from multiple sources, and the effectiveness of the strategy was evaluated. This strategy was tested in Bolivia, Cameroon, Mexico, and the Philippines, where decentralization of health services led to a need to strengthen the capacity of policy makers and health officers at sub-national levels to use information more effectively. Results showed that the DDM strategy improved evidence-based public health. Subsequently, DDM concepts and practices have been institutionalized in participating countries and at CDC.