Toxicity of nickel to a soil-dwelling springtail, Folsomia fimetaria (Collembola: Isotomidae).

Exposure of the collembolan Folsomia fimetaria L. to nickel via soil caused significant mortality and reduced growth and reproductive output. Nickel may be present in elevated concentrations due to anthropogenic discharge. Although collembolans are very numerous and important organisms in the soil ecosystem, the effect of nickel has not previously been studied on these organisms. The aim of this study was to investigate the toxic effects of high soil nickel concentrations on the collembolan F. fimetaria following a 3-week exposure in a loamy sand spiked with nickel up to 1000 mg Ni/kg. A 10% decrease in adult female numbers at 427 mg Ni/kg and at 645 mg Ni/kg for adult male numbers was observed for nickel-spiked soil. Juvenile numbers were reduced at 701 mg Ni/kg following a 3-week exposure. The corresponding EC50 values were 786 mg Ni/kg for females, 922 mg Ni/kg for males, and 859 mg Ni/kg for juveniles. The reproductive output seems to be the most sensitive parameter being reduced at soil nickel concentrations above 173 mg Ni/kg (EC10). Adult growth was not affected by soil nickel concentrations up to 1000 mg Ni/kg, but juvenile growth was reduced at concentrations above 480 mg Ni/kg (EC10).     

Genetic haplotypes of Th-2 immune signalling link allergy to enhanced protection to parasitic worms

Parasitic worm infection, allergy and asthma involve increased IgE production, eosinophil activity, mucus secretion and smooth muscle reactivity, effected through Th-2 immune signalling. These pathological features of allergic disorder, common in developed countries, appear to be protective features in resistance to parasitic worm infections prevalent in many developing countries. We investigated how genetic variation in the Th-2 signalling transduction molecule STAT6 relates to these clinical disorders, using immune phenotyping by serum IgE levels and haplotyping nine STAT6 genetic variants in a rural Chinese population, where Ascaris infection is prevalent, and an urban UK population where Ascaris is largely unknown but asthma and allergy are prevalent. We show for the first time that STAT6 haplotypes relate clearly to IgE levels, allergy and worm burden. The haplotypes segregated into two groups: those with raised IgE/low worm burden tended to have increased risk of allergic disorder, whereas low IgE/high worm burden tended to have a reduced risk of allergies. By estimating the mean worm burden for each haplotype in China and the relative risk of asthma for the matching haplotype in the UK, we draw a cross-population comparison and show a negative correlation between worm burden and expected risk of asthma. These data imply that the origin of common up-regulating variants of Th-2 signalling, involving STAT6, promotes asthma and allergy in developed countries, whereas in developing countries it protects against parasitic worm infections. Selective evolutionary mechanisms, driven by parasitic worm infection, may underlie the genetic contribution to risk of allergy and asthma in humans.     

Multiple-electrode radiofrequency ablations using Octopus(R)electrodes in an in vivo porcine liver model

Objectives

The objective of this study was to determine the in vivo efficacy of radiofrequency ablation (RFA) in porcine liver using Octopus® electrodes for creating a large coagulation compared with RFA using clustered electrodes.

Methods

A total of 39 coagulations were created using a 200-W generator and clustered electrodes or Octopus electrodes during laparotomy in 19 pigs. Radiofrequency was applied to the livers using four protocols: (1) Group A-1, monopolar mode using a clustered electrode (n=11); (2) Group A-2, monopolar mode using an Octopus electrode (n=11); (3) Group B-1, consecutive monopolar mode using three, clustered electrodes (n=8); and (4) Group B-2, switching monopolar mode using two Octopus electrodes (n=9). The energy efficiency, shape, diameters (D) and volume (V) of the coagulation volume were compared in each of the two groups.

Results

The mean maximum D and V of the coagulations in Group A-2 (4.7 cm and 33.1 cm³, respectively) were significantly larger than those in Group A-1 (4.1 cm and 20.3 cm³, respectively) (p<0.05). Furthermore, the mean minimum D, maximum D and V of the coagulations in Group B-2 were significantly larger than those in Group B-1, i.e. 5.3 vs 4.0 cm, 6.6 vs 4.9 cm and 66.9 vs 30.2 cm³, respectively (p<0.05). The energy efficiencies were also significantly higher in Groups A-2 and B-2 than in Groups A-1 and B-1 (p<0.05).

Conclusion

The Octopus electrodes were more efficient for creating a large ablation zone than clustered electrodes, and the efficacy of RFA with Octopus electrodes can be amplified in the switching monopolar mode.In recent years, image-guided percutaneous tumour ablation using radiofrequency (RF) energy has become increasingly popular and has gained wide acceptance as a valuable, minimally invasive treatment for primary and secondary liver malignancies [1]. Compared with conventional surgery, RF ablation (RFA) has many advantages in terms of reduced complications, morbidity and mortality as well as its cost-effectiveness. However, a major obstacle preventing the widespread use of RFA is its inability to reliably create adequate volumes of complete tumour destruction with sufficient safety margins, thus causing an increasing rate of marginal recurrence in large tumours due to the incomplete RFA. Most clinically available electrodes, including internally cooled electrodes, clustered electrodes, multitined expandable needle electrodes and perfusion electrodes, can induce coagulation necrosis in the range of 3–4 cm in diameter after a single ablation session [2,3]. Therefore, to treat liver tumours >3 cm in diameter, multiple overlapping ablations are often required to cover the entire tumour volume as well as the peripheral ablation margins [4,5]. However, in clinical practice, there is considerable difficulty repositioning the probe under ultrasound guidance during overlapping ablations as numerous microbubbles form in the heated tissue during RFA and may thus interfere with finding the electrode tip and the untreated portions of the target tumour on ultrasound [6].In order to avoid problems related to multiple overlapping ablations, including technical difficulties and a long procedure time, several approaches have been used to treat medium and large liver tumours. These include the use of cluster electrodes [7], multitined electrodes with saline infusion (RITA Medical Systems, Mountain View, CA) [2] and multiple electrodes in the switching monopolar mode or multipolar mode [8-11]. Although several previous studies demonstrated that the use clustered electrodes or multiple electrodes in the switching or multipolar modes could create larger coagulations [2,3,6,8-14], they also presented several potential unsolved problems. The clustered electrode problems include: (1) convergence of the three individual needles <5 mm; (2) limited access to the target tumour owing to narrow intercostal spaces; and (3) displacement of the liver due to its resistance to the electrode. Although RFA using multiple electrodes can successfully treat large liver tumours, it is still not widely used in clinical practice, primarily owing to its high cost and the complexity of using multiple electrodes.Recently, in order to improve the efficiency of clustered electrodes in creating a large ablation zone and to diminish any potential problems, we developed a separable clustered electrode (Octopus®; Taewoong Medical Co., Ltd, Goyang, Republic of Korea) with a specialised handle that can be incorporated into a larger handle in a single unit (Figure 1). Our electrode can be placed as a single electrode with variable interelectrode distances, according to the shape and size of the target tumour, or in a similar way to the clustered electrodes that are also composed of three electrodes as a single body at a fixed 5-mm interelectrode distance. Therefore, prior to their clinical application, we attempted to prove the in vivo efficacy of RFA using the Octopus electrodes to create a large area of coagulation necrosis in either the conventional or switching monopolar mode compared with RFA using a clustered electrode in porcine liver.Open in a separate windowFigure 1(a,b) Photographs of the Octopus® electrodes (Taewoong Medical Co., Ltd, Goyang, Republic of Korea), all of which have three individual needles. (c) Adaptor for the Octopus electrodes which connects the three cables to one port. (d) An illustration, which shows details of the connection between the needles and radiofrequency (RF) ablution system in a three Octopus electrodes system.     

Enhancement patterns of hepatocellular carcinomas on multiphasicmultidetector row CT: comparison with pathological differentiation

Objective The objective of this study was to determine the incidence of typical and atypical enhancement patterns of hepatocellular carcinomas (HCCs) on multiphasic multidetector row CT (MDCT) and to correlate the enhancement patterns and morphological image findings of HCC with the degree of tumour differentiation. Methods MDCT images of 217 patients with 243 surgically proven HCCs were evaluated through consensus reading by two radiologists. Our MDCT protocol was composed of precontrast, arterial, portal and delayed phases. The reviewers analysed the CT images for degree of attenuation; relative timing of washout; presence of dysmorphic intratumoral vessels, aneurysms and necrosis; tumour size; tumour margin; presence of pseudocapsule; intratumoral heterogeneity; and determined enhancement pattern. The imaging features were correlated with tumour differentiation using Fisher's exact test or the χ(2) test. Results Among 243 HCCs, 137 (56.4%) showed the typical enhancement pattern of HCC, which is arterial enhancement and washout on portal or equilibrium phase images. In the arterial phase, 190 of 243 (78.2%) HCCs showed hypervascularity, with approximately three quarters of poorly differentiated (PD) (34 of 45, 75.6%) and moderately differentiated (MD) HCCs (92 of 123, 74.8%) showing washout during the portal or delayed phases, vs only 50% of well-differentiated (WD) HCCs (11 of 22; p<0.048). The presence of intratumoral vessels and aneurysms, tumour necrosis, attenuation of precontrast, the relative timing of washout, intratumoral attenuation heterogeneity, tumour margin and tumour size were correlated with the pathological differentiation of HCCs (p<0.05). Conclusion A typical enhancement of HCCs on MDCT was not unusual (43.6%) and WD and PD HCCs account for most of the atypical enhancement patterns. Early washout favoured MD and PD HCCs rather than WD HCCs, whereas in our study the presence of intratumoral aneurysm was a highly specific finding for PD HCC.     

The development of the Be Active & Relax ¿Vitality in Practice¿ (VIP) project and design of an RCT to reduce the need for recovery in office employees

ABSTRACT: BACKGROUND: There is strong evidence to suggest that multiple work-related health problems are preceded by a higher need for recovery. Physical activity and relaxation are helpful in decreasing the need for recovery. This article aims to describe (1) the development and (2) the design of the evaluation of a daily physical activity and relaxation intervention to reduce the need for recovery in office employees. METHODS: The study population will consist of employees of a Dutch financial service provider. The intervention was systematically developed, based on parts of the Intervention Mapping (IM) protocol. Assessment of employees needs was done by combining results of face-to-face interviews, a questionnaire and focus group interviews. A set of theoretical methods and practical strategies were selected which resulted in an intervention program consisting of Group Motivational Interviewing (GMI) supported by a social media platform, and environmental modifications. The Be Active & Relax program will be evaluated in a modified 2 X 2 factorial design. The environmental modifications will be pre-stratified and GMI will be randomised on department level. The program will be evaluated, using 4 arms: (1) GMI and environmental modifications; (2) environmental modifications; (3) GMI; (4) no intervention (control group). Questionnaire data on the primary outcome (need for recovery) and secondary outcomes (daily physical activity, sedentary behaviour, relaxation/detachment, work- and health-related factors) will be gathered at baseline (T0), at 6 months (T1), and at 12 months (T2) follow-up. In addition, an economic and a process evaluation will be performed. DISCUSSION: Reducing the need for recovery is hypothesized to be beneficial for employees, employers and society. It is assumed that there will be a reduction in need for recovery after 6 months and 12 months in the intervention group, compared to the control group. Results are expected in 2013. Trial registration: Netherlands Trial Register (NTR): NTR2553 KEYWORDS: Need for recovery, relaxation, physical activity, environmental modifications, group motivational interviewing, employees, RCT.     

Toxicity of Nickel to the Earthworm and the Applicability of the Neutral Red Retention Assay

The toxic effects of nickel on survival, growth, and reproduction of Eisenia veneta were investigated following 4 weeks of exposure to a nickel-chloride spiked loamy sand soil. The ability of a simple earthworm biomarker, the lysosomal membrane stability of coelomocytes, to reflect nickel exposure was also studied. Nickel caused a significant toxic effect on E.veneta at soil concentrations above 85 mg Ni/kg. Reproduction (cocoon production) was the most sensitive parameter being reduced at soil concentrations above 85 mg Ni/kg (EC10 = 85 mg Ni/kg). Survival of adults was only reduced at concentrations above 245 mg Ni/kg, while adult and cocoon wet weight were not affected by soil nickel concentrations up to 700 mg Ni/kg. The lysosomal membrane stability, measured as neutral-red retention time, was reduced at soil nickel concentrations similar to those that reduced reproduction, and demonstrated a dose-response relationship. The neutral-red retention time showed large individual variation for the earthworms within each exposure concentration. It was concluded that the lysosomal membrane stability, measured as neutral red retention time, has a potential role in risk assessment, but care should be taken conducting this test.