Genotoxicity of synthetic amorphous silica nanoparticles in rats following short‐term exposure. Part 1: Oral route

Synthetic amorphous silica (SAS) in its nanosized form is now used in food applications although the potential risks for human health have not been evaluated. In this study, genotoxicity and oxidative DNA damage of two pyrogenic (NM‐202 and 203) and two precipitated (NM‐200 and ‐201) nanosized SAS were investigated in vivo in rats following oral exposure. Male Sprague Dawley rats were exposed to 5, 10, or 20 mg/kg b.w./day for three days by gavage. DNA strand breaks and oxidative DNA damage were investigated in seven tissues (blood, bone marrow from femur, liver, spleen, kidney, duodenum, and colon) with the alkaline and the (Fpg)‐modified comet assays, respectively. Concomitantly, chromosomal damage was investigated in bone marrow and in colon with the micronucleus assay. Additionally, malondialdehyde (MDA), a lipid peroxidation marker, was measured in plasma. When required, a histopathological examination was also conducted. The results showed neither obvious DNA strand breaks nor oxidative damage with the comet assay, irrespective of the dose and the organ investigated. Similarly, no increases in chromosome damage in bone marrow or lipid peroxidation in plasma were detected. However, although the response was not dose‐dependent, a weak increase in the percentage of micronucleated cells was observed in the colon of rats treated with the two pyrogenic SAS at the lowest dose (5 mg/kg b.w./day). Additional data are required to confirm this result, considering in particular, the role of agglomeration/aggregation of SAS NMs in their uptake by intestinal cells. Environ. Mol. Mutagen. 56:218–227, 2015. © 2014 Wiley Periodicals, Inc.     

Validity of the neck disability index,Northwick Park neck pain questionnaire,and problem elicitation technique for measuring disability associated with whiplash-associated disorders

The Neck Disability Index (NDI) and Northwick Park Neck Pain Questionnaire (NPQ) were developed to measure self-perceived disability from neck pain, including that which may arise from whiplash injury. However, there is little data specifically concerning their validity for whiplash-associated disorders (WAD). The aim of this study was to assess the validity of the NDI and NPQ as measures of outcome in WAD by comparing them to a patient preference questionnaire, the problem elicitation technique (PET), which identifies problems that are of most importance to the individual patient. A cross-sectional study of 71 patients with varying severity and duration of WAD were recruited from a private physiotherapy practice. All patients completed a standardized self-administered questionnaire that included demographic and clinical details as well as self-perceived pain and severity of symptoms, NDI and NPQ. A trained interviewer administered the PET. Construct validity of the disability measures was examined by determining their correlation with each other and with pain and severity of symptoms by calculating Pearson's correlation coefficients. Content validity of the NDI and NPQ was assessed by comparing the items of both questionnaires to the problems identified by the PET. Participants' mean age was 40.1 years (SD=14.3) and 59 were women (83.1%). Most patients were in WAD category I (n=23, 32.1%), or II (n=42, 59.2%). Mean NDI, NPQ, and PET scores were 40.7 (SD=17.0), 38.7 (SD=15.8), and 160.2 (SD=92.0, range 6.0-509.5), respectively. Correlations between the NDI and PET, NPQ and PET, and NDI and NPQ were r=0.57, 0.56 and 0.88, respectively. The PET identified an average of 7.7 problems per patient (SD=4.2, range 1-17 problems). Problems most commonly identified were work for wages (52.1%), fatigued during the day (50.7%), participation in sports (47.9%), depression (43.7%), drive a car (43.7%), socialize with friends (33.8%), sleep through the night (31.0%), frustration (31.0%), and anger (28.2%). Only three of these problems are included in the NDI (work, driving, and sleeping) and only four are included in the NPQ (work, driving, sleeping, and social activities). While both the NDI and NPQ include some problems that are common in patients with WAD, frequently identified problems, such as emotional and social items are absent. In contrast to the PET, neither instrument captures the full spectrum of disabilities judged to be important by the patient.     

Comparison of estimates of left ventricular ejection fraction obtained from gated blood pool imaging,different software packages and cameras

Serial measurement of LVEF using gated blood pool (GBP) imaging is an established technique for monitoring LVEF in patients undergoing chemotherapy with cardiotoxic medication and in patients after heart transplants.11,2 The nuclear medicine department at Groote Schuur Hospital performs up to a thousand GBP studies annually. The majority of these studies are for patients receiving cardiotoxic chemotherapy and have a significant impact on patient management.In our hospital, the radiation oncologists consider not starting cardiotoxic chemotherapy if the LVEF is below 50% and terminating chemotherapy if there is a 10% decrease. In patients who have had heart transplants, the cardiologists start patients on glucocorticosteroids if a patient’s LVEF decreases by10%. It is therefore imperative that serial studies on an individual patient are comparable.Two software systems are used in our nuclear medicine department. The Siemens system (Siemens Medical Solutions, Chicago, USA) was introduced in February 2006 and the Hermes system (Hermes Medical Solutions, Stockholm Sweden) in September 2007. After the introduction of the Hermes system, we found large differences between the LVEFs calculated by the two systems. This was confirmed by a pilot study and is consistent with the literature that different software programs for processing equilibrium gated radionuclide studies cannot be used interchangeably.3-7The department also uses two different cameras, a General Electric (GE) Starcam 400 AC single-head and a Siemens Signature Series e.cam dual-head camera to acquire the raw data. These are then transferred to the Siemens and Hermes processing systems.This study was done to determine how the software packages used for processing GBP studies should be integrated into our department and if the use of different cameras for acquisition influences results. The study had two components. The first examined the values and reproducibility of estimates of LVEF from two software packages using data acquired on the GE gamma camera and processed independently by three operators. The second component examined the values and reproducibility of estimates of LVEF calculated with the same software packages using matched pairs of raw data acquired on both gamma cameras (GE and Siemens) processed by one operator.