American Cancer Society nutrition and physical activity guideline for cancer survivors

The overall 5-year relative survival rate for all cancers combined is now 68%, and there are over 16.9 million survivors in the United States. Evidence from laboratory and observational studies suggests that factors such as diet, physical activity, and obesity may affect risk for recurrence and overall survival after a cancer diagnosis. The purpose of this American Cancer Society guideline is to provide evidence-based, cancer-specific recommendations for anthropometric parameters, physical activity, diet, and alcohol intake for reducing recurrence and cancer-specific and overall mortality. The audiences for this guideline are health care providers caring for cancer survivors as well as cancer survivors and their families. The guideline is intended to serve as a resource for informing American Cancer Society programs, health policy, and the media. Sources of evidence that form the basis of this guideline are systematic literature reviews, meta-analyses, pooled analyses of cohort studies, and large randomized clinical trials published since 2012. Recommendations for nutrition and physical activity during cancer treatment, informed by current practice, large cancer care organizations, and reviews of other expert bodies, are also presented. To provide additional context for the guidelines, the authors also include information on the relationship between health-related behaviors and comorbidities, long-term sequelae and patient-reported outcomes, and health disparities, with attention to enabling survivors' ability to adhere to recommendations. Approaches to meet survivors' needs are addressed as well as clinical care coordination and resources for nutrition and physical activity counseling after a cancer diagnosis.     

Suboptimal performance of rotavirus testing in a vaccinated community population should prompt laboratories to review their rotavirus testing algorithms in response to changes in disease prevalence

Rotavirus vaccine has reduced disease prevalence in many countries. Consequently, we aimed to assess the reliability of a rotavirus immunoassay in the community population of Auckland and Northland, New Zealand. Between 22 October 2015 and 31 December 2016, 2873 fecal samples were tested by enzyme immunoassay (EIA, Rotascreen II, Microgen, UK) from 2748 patients (median age 8?years, range 0–101?years). Eighty-nine (3.1%) samples were reactive; 86 samples were tested by a second method. Rotavirus was confirmed in 49/86 (57%). Positive rotavirus EIAs were more likely to be confirmed in samples from cases ≥1?year of age (positive predictive value [PPV] 61%, 95% confidence interval [CI] 50–72%, P?=?0.049) and in spring/summer (PPV 67%, 95% CI 55–78%, P?=?0.003). Reactive rotavirus tests required confirmatory testing regardless of demographic, vaccine, or seasonal factors; a review of rotavirus testing algorithms may be necessary in other vaccinated community populations.     

Homing defects of B cells in HIV-1 infected children impair vaccination responses

Background

Successful vaccinations rely on antibody responses. Chemokine receptors play an important role in B cell homing to differentiation niches. We assessed CXCR4, CXCR5 and CCR6 expression on B cells during HIV-1 infection and relate it to antibody responses against a HBV vaccine.

Bisphosphonate-associated peri-implant fractures: a new clinical entity?: A series of 10 patients with 11 fractures

Background and purpose

The current definition of atypical femoral fractures (AFFs) associated with bisphosphonate use includes only de novo fractures. However, in recent years reports of bisphosphonate-associated periprosthetic fractures involving stemmed arthroplasty implants have emerged. In a case series of peri-implant fractures in femurs with plate/screw constructs, we aimed to assess similarities with classical AFFs and how their location may have implications for the pathogenesis and management of AFFs.

Patients and methods

We retrospectively identified 10 patients with 11 peri-implant fractures.

Results

The patients were ambulant women, mean age 80 (70–92) years. Mean duration of bisphosphonate use was 5 (1–10) years. The peri-implant fractures were sustained an average of 4 years (6 months to 9 years) from the time of index surgery. They were all associated with low-energy mechanisms. 8 fractures occurred near the tip of a plate, while 3 traversed the penultimate screwhole of a plate. The peri-implant fractures showed clinical and radiological features of atypicality such as lateral cortical thickening, simple fracture pattern, and lack of comminution. The patients underwent revision surgery, with bone grafting used in all but 1 case. Radiological union was evident after 2–4 months.

Interpretation

Atypical peri-implant fractures of the femur associated with bisphosphonate use may be a new entity. Stress lesions and atypical fractures may tend to develop over stress risers along the operated femur. This finding has implications for the pathogenesis and clinical management of AFFs.Bisphosphonates form the cornerstone of antiresorptive therapy in the management of post-menopausal osteoporosis. They are used in the treatment of malignant and osteoclast-mediated metabolic bone disease. Their use in patients who have undergone total joint arthroplasty of the lower limb is associated with higher periprosthetic bone mineral density and longer implant survival (Bhandari et al. 2005). Bisphosphonates exert their therapeutic effect by reducing bone turnover and increasing overall mineralization. This translates to increased bone mineral density and bone strength, corresponding clinically to reduced risk of vertebral and non-vertebral fragility fractures (Black et al. 1996).In recent years, several published reports have described atypical femoral fractures (AFFs) of the proximal femoral diaphysis and subtrochanteric region, in association with bisphosphonate use (Goh et al. 2007, Neviaser et al. 2008, Isaacs et al. 2010). Bisphosphonates are associated with a higher age-adjusted relative risk of AFF in women than in men, which is higher in alendronate users than in risedronate users (Schilcher et al. 2015). Bisphosphonates may cause changes in bone matrix composition and bone mechanical properties, increasing the propensity for accumulation of microdamage. Impaired target remodeling would contribute to the progression of macrocracks. High interfragmentary strain from physiological loads at a thin fracture line may be a mechanical factor in lack of bone healing (Aspenberg et al. 2010).Periprosthetic/peri-implant fractures are currently excluded from the definition of AFFs. We suggest that peri-implant fractures of the femur with features of atypicality may be linked to bisphosphonate use and that they should be recognized as a clinical entity.     

From the Cover: Contribution of cyanobacterial alkane production to the ocean hydrocarbon cycle

Hydrocarbons are ubiquitous in the ocean, where alkanes such as pentadecane and heptadecane can be found even in waters minimally polluted with crude oil. Populations of hydrocarbon-degrading bacteria, which are responsible for the turnover of these compounds, are also found throughout marine systems, including in unpolluted waters. These observations suggest the existence of an unknown and widespread source of hydrocarbons in the oceans. Here, we report that strains of the two most abundant marine cyanobacteria, Prochlorococcus and Synechococcus, produce and accumulate hydrocarbons, predominantly C15 and C17 alkanes, between 0.022 and 0.368% of dry cell weight. Based on global population sizes and turnover rates, we estimate that these species have the capacity to produce 2–540 pg alkanes per mL per day, which translates into a global ocean yield of ∼308–771 million tons of hydrocarbons annually. We also demonstrate that both obligate and facultative marine hydrocarbon-degrading bacteria can consume cyanobacterial alkanes, which likely prevents these hydrocarbons from accumulating in the environment. Our findings implicate cyanobacteria and hydrocarbon degraders as key players in a notable internal hydrocarbon cycle within the upper ocean, where alkanes are continually produced and subsequently consumed within days. Furthermore we show that cyanobacterial alkane production is likely sufficient to sustain populations of hydrocarbon-degrading bacteria, whose abundances can rapidly expand upon localized release of crude oil from natural seepage and human activities.Hydrocarbons are ubiquitous in the oceans, where natural seepage and human activities are estimated to release between 0.4 and 4.0 million tons of crude oil into the ocean ecosystem annually (1). Even in minimally polluted marine surface waters, alkanes such as pentadecane and heptadecane have been found at concentrations ranging from 2 to 130 pg/mL (2, 3), although their sources remain unclear. A small proportion of alkanes, from 1 to 60 fg/mL, is associated with particulate matter >0.7 µm in diameter (4). Larger amounts may be associated with particulate matter <0.7 µm in diameter, because ocean concentrations are higher than the solubility of pentadecane and heptadecane, which is ∼10 pg/mL and 1 pg/mL, respectively (2). Populations of hydrocarbon-degrading bacteria, referred to as hydrocarbonoclastic bacteria, including many species that cannot use other carbon sources, are present in marine systems and play an important role in turnover of these compounds (5–9). Because obligate hydrocarbon-degrading bacteria are found in waters without significant levels of crude oil pollution, these organisms must use an alternate hydrocarbon source (9–11).Here, we investigate the extent to which cyanobacteria may contribute to these marine hydrocarbon pools. Cyanobacteria (oxygenic photosynthetic bacteria) can synthesize C15 to C19 hydrocarbons via two separate pathways. The first produces alkanes, predominantly pentadecane, heptadecane, and methyl-heptadecane, in addition to smaller amounts of alkenes, via acyl-ACP reductase (FAR) and aldehyde deformylating oxygenase (FAD) enzymes (12). The second pathway generates alkenes, primarily nonadecene and 1,14-nonadecadiene, via a polyketide synthase enzyme (Ols) (13). The abundance and ubiquity of cyanobacteria in the marine environment suggests hydrocarbon production in the oceans could be considerable and broadly distributed geographically (14, 15).We focused our studies on the two most abundant marine cyanobacteria, Prochlorococcus and Synechococcus (16). These genera have estimated global population sizes of 2.9 ± 0.1 × 10²⁷ and 7.0 ± 0.3 × 10²⁶ cells, respectively (14), and are together responsible for approximately a quarter of marine net primary production (14). These are also the only cyanobacterial genera for which global population size estimates have been compiled (14). Although the distribution patterns of both genera overlap (14, 17), Prochlorococcus cells dominate low-nutrient open-ocean areas between 40°N and 40°S and can be found at depths of up to 200 m (16, 18). Synechococcus are more numerous in coastal and temperate regions where conditions and nutrient levels are more variable (14, 16) but are still widely distributed in high abundance.     

A prospective 3-year study of fixed bridges linking Astra Tech ST implants to natural teeth

BACKGROUND: Connecting teeth and osseointegrated implants in fixed reconstructions is not generally recommended because of differences in their response to loading. AIM: The aim of the present study was to assess the clinical and radiographic performance of the teeth and implants used to support three unit fixed bridges subjected to normal functional loads. SUBJECTS AND METHODS: Nineteen subjects (10 males, nine females, age range 27-65 years) with an edentulous posterior free end saddle in either maxilla or mandible (Kennedy Class 2), and opposing natural teeth or a tooth-supported fixed bridge were treated and completed the 3-year trial. An Astra Tech ST implant (length: 9 mm (n=2), 11 mm (n=9) or 13 mm (n=8); diameter: 4.5 mm) was placed immediately distal to the last tooth or leaving a single premolar sized space. The distal tooth received a gold coping and the implant was restored with a customised Prepable abutment (Astra Tech Profile BiAbutment: diameter 5.5 or 7 mm). A fixed bridge was placed linking the gold coping and implant abutment either with the pontic as a distal cantilever (n=6, length 7-8 mm) or as a fixed-fixed design (n=13, length 6-12 mm). Standardised radiographs and clinical records were taken at delivery of the prosthesis (baseline BL) and annually. RESULTS: Plaque scores at implant sites increased between BL and subsequent years (P<0.02). Statistically significant increases in probing depth were observed at both abutment teeth and implants between baseline and subsequent years (P<0.001). Marginal bone levels (mm) at the implant and tooth were stable between BL, 1-, 2- and 3-year examinations (implant: BL 0.65+/-0.42, 1 year 0.63+/-0.47, 2 years 0.88+/-0.55, 3 years 0.78+/-0.64; tooth: BL 2.29+/-0.82, 1 year 2.41+/-0.8, 2 years 2.38+/-1.02, 3 years 2.68+/-0.86). No signs of the intrusion of the abutment teeth were detected. One case of abutment screw loosening occurred. Eight bridges required re-cementation with a permanent cement in place of the temporary cement. There were eight subjects presenting with fractures/chips to the composite component of the bridges. CONCLUSION: The 3-year results demonstrate fully functional successful restorations with no evidence of tooth intrusion and with stable bone levels at both teeth and implants.