Problems in evaluating the health impacts of radio frequency radiation

In an effort to clarify the nature of causal evidence regarding the potential impacts of RFR on biological systems, this paper relies on a well-established framework for considering causation expanded from that of Bradford Hill, that combines experimental and epidemiological evidence on carcinogenesis of RFR. The Precautionary Principle, while not perfect, has been the effective lodestone for establishing public policy to guard the safety of the general public from potentially harmful materials, practices or technologies. Yet, when considering the exposure of the public to anthropogenic electromagnetic fields, especially those arising from mobile communications and their infrastructure, it seems to be ignored. The current exposure standards recommended by the Federal Communications Commission (FCC) and International Commission on Non-Ionizing Radiation Protection (ICNIRP) consider only thermal effects (tissue heating) as potentially harmful. However, there is mounting evidence of non-thermal effects of exposure to electromagnetic radiation in biological systems and human populations. We review the latest literature on in vitro and in vivo studies, on clinical studies on electromagnetic hypersensitivity, as well as the epidemiological evidence for cancer due to the action of mobile based radiation exposure. We question whether the current regulatory atmosphere truly serves the public good when considered in terms of the Precautionary Principle and the principles for deducing causation established by Bradford Hill. We conclude that there is substantial scientific evidence that RFR causes cancer, endocrinological, neurological and other adverse health effects. In light of this evidence the primary mission of public bodies, such as the FCC to protect public health has not been fulfilled. Rather, we find that industry convenience is being prioritized and thereby subjecting the public to avoidable risks.

A new 90-day drinking water study of sodium cyanide in rats to further evaluate National Toxicology Program findings and inform risk assessment

BACKGROUND

The National Toxicology Program (NTP, 1993) reported male reproductive effects in a sodium cyanide (NaCN) drinking water study. The critical effect, decreased cauda epididymis weights, was used by U.S. Environmental Protection Agency for their hazard characterization and risk assessment of hydrogen cyanide and cyanide salts. To further investigate potential male reproductive effects, we conducted a new 90-day drinking water study.

METHODS

Our study expanded evaluations of testes and thyroid. Male F344 rats received NaCN in drinking water at 0, 0 (water restricted; paired to top dose), 3, 10, 30, 100, and 300 ppm for 13 weeks, followed by 10-weeks recovery.

RESULTS

Plasma thiocyanate increased dose-dependently but returned to baseline during recovery. NaCN caused neither effects on survival, body weight, food consumption, hematology, serum chemistry, urinalysis, thyroid hormones, testes or epididymides weights, sperm motility/viability, sperm morphology, or sperm production; nor clinical, ophthalmic, or histopathologic findings. Increased organ weights in thyroid/parathyroid and liver occurred at 300-ppm but were recoverable. No changes occurred in male reproductive organs.

CONCLUSIONS

Absent adverse effects, the NOAEL was 300 ppm (21.66 mg/kg/day; highest dose tested). Based on organ weight increases at 300 ppm, the NOEL was 100 ppm (7.46 mg/kg/day).

Do private health providers adhere to National Tuberculosis Guideline while assigning treatment outcome? Findings from a lower middle-income country

Background

Treatment success rate is an important indicator to measure the performance of the National Tuberculosis Program (NTP). There are concerns about the quality of outcome data from private facilities engaged by NTP. Adherence of private providers of tuberculosis care to NTP guideline while assigning treatment outcomes to patients is rarely investigated. We aimed to determine whether Lagos private for-profit (PFP) and private not-for-profit (PNFP) facilities adhere to domestic TB guideline while assigning treatment outcome and the availability of periodic sputum acid-fast bacilli (AFB) results.

Method

A retrospective review of facility treatment register and treatment cards of TB patients managed between January and December 2016 across 10 private directly observed treatment short-course (DOTS) facilities involved in the public-private mix (PPM) in Lagos, Nigeria. The study took place between January and June 2019.

Results

Of the 1,566 patients, majority (60.7%) were male, >30 years (50.2%), HIV-negative (88.4%), and attended PNFP (78.5%). The reported treatment success rate (TSR) was 84.2% while the actual TSR was 53.8%. In total, 91.1, 77.6, and 70.3% of patients had sputum acid-fast bacilli (AFB) at 2/3, month 5, and month 6, respectively, while 68.6% had all the three sputum AFB in the register. Healthcare workers (HCWs) were adherent in assigning treatment outcome for 65.6% of TB patients while 34.4% of patients were assigned incorrect treatment outcomes. Most variations between reported and actual treatment outcomes were found with cured (17%) and completed (13.4%). Successful and unsuccessful outcomes were overreported by 30.4% and 4.1%, respectively. DOTS providers in private facilities with available TB guideline (OR 8.33, CI 3.56-19.49, p < 0.0001) and PNFP facility (OR 4.42, CI 1.91-10.3, p = 0.001) were more likely to adhere to National TB Guideline while assigning TB treatment outcome.

Conclusion

Frontline TB providers in Lagos private hospitals struggled with assigning correct treatment outcome for TB patients based on NTBLCP guideline. Increased access to all the periodic follow-up AFB tests for TB patients on treatment and availability of National TB Guideline for referencing could potentially improve the adherence of private TB service providers while assigning TB treatment outcomes.

A modeling concept on removal of VOCs in wire-tube non-thermal plasma, considering electrical and structural factors

In this study, benzene was selected as an indicator of VOCs, and a modeling procedure was carried out on benzene removal (outflow concentration of benzene, C/inflow concentration of benzene, C₀), in DC and AC non-thermal plasma systems. Different diameters (18, 23, and 36 mm) of wire-tube plasma reactors were prepared, and models were raised based on the results of experiments with influencing factors of the used voltage, gap size inside the reactor, current density, and specific energy. The results showed correlation between the factors and benzene removal in both DC and AC discharge non-thermal plasma. The applied voltage as an electrical factor had negative correlation with C/C₀, and the correlation was stronger than for gap size which was positively correlated with C/C₀. Current density and specific energy were affected by the voltage and gap size of the reactor; the lowest C/C₀ values were obtained in the highest values of specific energy and current density. Regarding the raised models, multi-factor exponential model was the most reliable one with the results.

Quantifying association between liver tumor incidence and early-stage liver weight increase - An NTP data analysis

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Liver tumor incidence and liver weight data were collected from 593 NTP studies.

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Correlation between BMDs from these two types of data were quantified.

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In a general analysis, the correlation coefficient can be as high as 0.78.

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Early liver weight change may be used as an indicator for chemical tumorigenesis.

Two-year toxicology and carcinogenesis rodent studies conducted at the National Toxicology Program (NTP) are used to identify potential adverse health effects in humans due to chemical exposure, including cancer. Liver tumor, the most frequently diagnosed tumor type of chemically induced neoplastic effects documented in NTP’s carcinogenicity studies, is usually difficult to be detected at early stage due to the inconspicuous symptoms. However, the abnormal growth of liver cells can lead to liver weight increase, so it is hypothesized that liver tumor incidence is associated with early stage liver weight increase. In this study, the association between liver weight increase and liver tumor incidence are quantified by (1) calculating the correlation coefficient of and (2) building quantitative linear relationship between benchmark dose estimates derived from these two types of data collected from NTP studies. Together with 151 chemical/species/sex combinations of liver tumor data showing positive evidence collected from 76 NTP long-term studies, short-term liver weight data reported in the same NTP report were extracted to be paired with the liver tumor data for the analyses. Results show that the estimated correlation coefficients (as high as 0.78) along with the adequately fitted linear models suggest that the association between relative liver weight increase and aggregated liver tumor incidence are relatively strong. Additional analyses focused on some more specific situations (e.g., specific tumor type or specific strain/sex combination) further confirmed the strong association. Given the design of this study, the interpretation of the findings is not that liver weight increase can be used to predict liver tumor incidence, instead, evident increase in liver weight might be used as a reason to prioritize the test article for a two-year toxicology and carcinogenesis study.

Sputum smear-positive, Xpert® MTB/RIF-negative results: magnitude and treatment outcomes of patients in Myanmar

Setting: Myanmar's National Tuberculosis Programme (NTP) uses the Xpert^® MTB/RIF assay to diagnose rifampicin (RMP) resistance in sputum smear-positive (Sm+) pulmonary tuberculosis (TB) patients. The Xpert test may occasionally yield negative results (Xpert-) for Mycobacterium tuberculosis complex, indicating a false-positive sputum smear result, false-negative Xpert result or infection with non-tuberculous mycobacteria (NTM). Patients with NTM may respond poorly to first-line anti-tuberculosis treatment. Objective: To assess the burden of Sm+, Xpert- results at the national level and treatment outcomes of Sm+, Xpert- patients in Yangon Region. Design: A cohort study involving a retrospective record review of routinely collected NTP data. Result: In 2015 and 2016, 4% of the 25 359 Sm+ patients who underwent Xpert testing nationally were Sm+, Xpert-. Similarly, in the Yangon Region, 5% of the 5301 Sm+ patients were also Xpert- and were treated with first-line anti-tuberculosis regimens. Smear grade (scanty/1+) and age ⩾65 years were associated with Sm+, Xpert- results. The 88% treatment success rate for this group was similar to that of Sm+, Xpert+ patients without RMP resistance. Conclusion: Approximately 4-5% of Sm+ TB patients were Xpert-. There is an urgent need to formulate guidelines on how to reassess and manage these patients.

Recombinant cell-lysate-catalysed synthesis of uridine-5'-triphosphate from nucleobase and ribose, and without addition of ATP

Nucleoside triphosphates (NTPs) are important synthetic targets with diverse applications in therapeutics and diagnostics. Enzymatic routes to NTPs from simple building blocks are attractive, however the cost and complexity of assembling the requisite mixtures of multiple enzymes hinders application. Here, we describe the use of an engineered E. coli cell-free lysate as an efficient readily-prepared multi-enzyme biocatalyst for the production of uridine triphosphate (UTP) from free ribose and nucleobase. Endogenous lysate enzymes are able to support the nucleobase ribosylation and nucleotide phosphorylation steps, while uridine phosphorylation and the production of ribose phosphates (ribose 1-phosphate, ribose 5-phosphate and phosphoribosyl pyrophosphate) require recombinant enrichment of endogenous activities. Co-expression vectors encoding all required recombinant enzymes were employed for host cell transformation, such that a cell-free lysate with all necessary activities was obtained from a single bacterial culture. ATP required as phosphorylation cofactor was recycled by endogenous lysate enzymes using cheap, readily-prepared acetyl phosphate. Surprisingly, acetyl phosphate initiated spontaneous generation of ATP in the lysate, most likely from the breakdown of endogenous pools of adenosine-containing starting materials (e.g. adenosine cofactors, ribonucleic acids). The sub-stoichiometric amount of ATP produced and recycled in this way was enough to support all ATP-dependent steps without addition of any exogenous cofactor or auxiliary enzyme. Using this approach, equimolar solutions of orotic acid and ribose are transformed near quantitatively into 1.4 g L^-1 UTP within 2.5 h, using a low-cost, readily-generated biocatalytic preparation.

Ultrafine NaTi2(PO4)3 Nanoparticles Encapsulated in N-CNFs as Ultra-Stable Electrode for Sodium Storage

We present a feasible method for the preparation of one-dimensional N-doping carbon nanofibers encapsulated NaTi2(PO4)3 (NTP-NCNFs) through electrospinning accompanied by calcination. The poor electrical conductivity of NTP is significantly improved and the as-prepared NTP-NCNFs exhibit stable and ultrafast sodium-storage capability. The NTP-NCNFs maintains a stable specific capacity of 121 mAh g-1 at 10 C after 2,000 cycles, which only drop to 105 mAh g-1 after 20,000 cycles. Furthermore, the NTP-NCNFs show excellent rate performance from 0.2 to 20 C, whose recovery efficiency still reaches 99.43%. The superior electrochemical property is mainly attributed to the large specific surface area, high porosity, N-doping carbon coating, and one-dimensional structure of NTP-NCNFs.

Nomogram integrating gene expression signatures with clinicopathological features to predict survival in operable NSCLC: a pooled analysis of 2164 patients

Background

The current tumor-node-metastasis (TNM) staging system is insufficient to predict outcome of patients with operable Non-Small Cell Lung Cancer (NSCLC) owing to its phenotypic and genomic heterogeneity. Integrating genomic signatures with clinicopathological factors may provide more detailed evaluation of prognosis.

Methods

All 2164 clinically annotated NSCLC samples (1326 in the training set and 838 in the validation set) with corresponding microarray data from 17 cohorts were pooled to develop and validate a clinicopathologic-genomic nomogram based on Cox regression model. Two computational methods were applied to these samples to capture expression pattern of genomic signatures representing biological statuses. Model performance was measured by the concordance index (C-index) and calibration plot. Risk group stratification was proposed for the nomogram.

Results

Multivariable analysis of the training set identified independent factors including age, TNM stage, combined prognostic classifier, non-overlapping signature, and the ratio of neutrophil to plasma cells. The C-index of the nomogram for predicting survival was statistically superior to that of the TNM stage (training set, 0.686 vs 0.627, respectively; P < .001; validation set, 0.689 vs 0.638, respectively; P < .001). The calibration plots showed that the predicted 1-, 3- and 5-year survival probabilities agreed well with the actual observations. Stratifying patients into three risk groups detected significant differences among survival curves.

Conclusions

These findings offer preliminary evidence that genomic data provide independent and complementary prognostic information and incorporation of this information can refine prognosis in NSCLC. Prospective studies are required to further explore the value of this composite model for prognostic stratification and tailored therapeutic strategies.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0477-x) contains supplementary material, which is available to authorized users.

Recent adaptations of fluorescence techniques for the determination of mechanistic parameters of helicases and translocases

Helicases and translocases are nucleic acid (NA)-based molecular motors that use the free energy liberated during the nucleoside triphosphate (NTP, usually ATP) hydrolysis cycle for unidirectional translocation along their NA (DNA, RNA or heteroduplex) substrates. Determination of the kinetic and thermodynamic parameters of their mechanoenzymatic cycle serves as a basis for the exploration of their physiological behavior and various cellular functions. Here we describe how recent adaptations of fluorescence-based solution kinetic methods can be used to determine practically all important mechanistic parameters of NA-based motor proteins. We outline practically useful analysis procedures for equilibrium, steady-state and transient kinetic data. This analysis can be used to quantitatively characterize the enzymatic steps of the NTP hydrolytic cycle, the binding site size, stoichiometry and energetics of protein-NA interactions, the rate and processivity of translocation along and unwinding of NA strands, and the mechanochemical coupling between these processes. The described methods yield insights into the functional role of the enzymes, and also greatly aid the design and interpretation of single-molecule experiments as well as the engineering of enzymatic properties for biotechnological applications.

Measuring the adherence energy of the resin-metal interface with two fracture mechanics methods: The DCB and NTP tests

OBJECTIVE

To evaluate the abilities of the DCB and the NTP test for measuring adherence of an adhesive joint between a resin and a metal interface.

METHODS

Two-hundred stainless steel metal beams (diam. 50×5×2 mm) were cast and treated by the following methods: (1) sandblasting with aluminum oxide, followed by treatment with (2) the Rocatec system or (3) the Alloy primer. Superbond and Panavia F 2.0 were used as adhesives. The fracture energy (G1C) and fracture toughness (K1C) of two adhesives were compared by two-way analysis of variance.

RESULTS

With the DCB test, Superbond was more effective than Panavia, regardless of the surface treatment and conditions of crack propagation. The overall effectiveness of the treatments was in the following order: sandblasting + Rocatec > sandblasting alone > sandblasting + Alloy primer. The adherence energy in an aqueous medium was lower than that in air. With the NTP test, similar performances were obtained with three surface treatments. However, the potential of Rocatec seemed slightly higher.

CONCLUSIONS

The DCB and NTP tests provide independent measures of the inherent value of an adhesive. Rocatec appeared to provide greater resistance of the bonded joints in an aqueous environment.

My Winding Road: From Microbiology to Toxicology and Environmental Health

I would certainly never have predicted that I would become the director of the National Institute of Environmental Health Sciences (NIEHS) and the National Toxicology Program (NTP) when I was a Jewish girl growing up in Teaneck, New Jersey. My family stressed the importance of education. Yet for a girl there were many not-so-subtle suggestions that the appropriate careers were in teaching or nursing, and the most important thing was to be a wife and mother. Well, I can't disagree with the latter, although I would have to add grandmother to that list of achievements. My parents were both college graduates, but my mom only taught high school English for one year before leaving the field to start our family. My dad returned from World War II and joined his brother in accounting. After my first sister was born, my father joined my mother's family jewelry business and helped to open a second retail store. My mother helped my dad out during the busy times—Christmas and wedding season—but otherwise focused on our growing family of three girls and one boy. This became increasingly challenging when it became clear that my little brother was severely retarded and would require extra care.

The trend of tuberculosis cases over 60 years in Fiji's largest treatment centre: 1950-2010

SETTING

P J Twomey Hospital, National Tuberculosis Programme, Fiji.

OBJECTIVES

To review the trend in numbers of tuberculosis (TB) cases registered each year from 1950 to 2010 at P J Twomey Hospital, Fiji's largest TB treatment centre and central TB unit, and to consider trends in the context of key TB control events in Fiji.

DESIGN

Descriptive study of data from medical records and TB registers, including age, sex, ethnicity, TB diagnosis and smear result.

RESULTS

Between 1950 and 2010, 14 616 cases were registered at P J Twomey Hospital. Of these, 58% were male, 70% were indigenous Fijians (i-taukei) and 64% were aged 15-49 years. The caseload dropped sharply in the 1960s, and has fallen steadily since 1990. Smear results were available for the majority of cases (91%). Between 1950 and 1985, smear-positive cases accounted for 19% of cases overall; this increased to 41% after 1985 following laboratory training. The numbers of sputum smear-positive cases recorded each year has been increasing in the last decade.

CONCLUSION

There have been marked changes in TB caseload over the last 60 years at Fiji's largest TB treatment centre. The recent increase in smear-positive cases while total TB cases have been falling needs further evaluation.

Characteristics and treatment outcomes of tuberculosis retreatment cases in three regional hospitals, Uganda

SETTING

Three regional referral hospitals in Uganda with a high burden of tuberculosis (TB) and human immunodeficiency virus (HIV) cases.

OBJECTIVE

To determine the treatment outcomes of TB retreatment cases and factors influencing these outcomes.

DESIGN

A retrospective cohort study of routinely collected National Tuberculosis Programme data between 1 January 2009 and 31 December 2010.

RESULTS

The study included 331 retreatment patients (68% males), with a median age of 36 years, 93 (28%) of whom were relapse smear-positive, 21 (6%) treatment after failure, 159 (48%) return after loss to follow-up, 26 (8%) relapse smear-negative and 32 (10%) relapse cases with no smear performed. Treatment success rates for all categories of retreatment cases ranged between 28% and 54%. Relapse smear-positive (P = 0.002) and treatment after failure (P = 0.038) cases were less likely to have a successful treatment outcome. Only 32% of the retreatment cases received a Category II treatment regimen; there was no difference in treatment success among patients who received Category II or Category I treatment regimens (P = 0.73).

CONCLUSION

Management of TB retreatment cases and treatment success for all categories in three referral hospitals in Uganda was poor. Relapse smear-positive or treatment after failure cases were less likely to have a successful treatment outcome.

NIEHS/FDA CLARITY-BPA research program update

Bisphenol A (BPA) is a chemical used in the production of numerous consumer products resulting in potential daily human exposure to this chemical. The FDA previously evaluated the body of BPA toxicology data and determined that BPA is safe at current exposure levels. Although consistent with the assessment of some other regulatory agencies around the world, this determination of BPA safety continues to be debated in scientific and popular publications, resulting in conflicting messages to the public. Thus, the National Toxicology Program (NTP), National Institute of Environmental Health Sciences (NIEHS), and U.S Food and Drug Administration (FDA) developed a consortium-based research program to link more effectively a variety of hypothesis-based research investigations and guideline-compliant safety testing with BPA. This collaboration is known as the Consortium Linking Academic and Regulatory Insights on BPA Toxicity (CLARITY-BPA). This paper provides a detailed description of the conduct of the study and a midterm update on progress of the CLARITY-BPA research program.

The National Toxicology Program Web-based nonneoplastic lesion atlas: a global toxicology and pathology resource

Toxicologists and pathologists worldwide will benefit from a new, website-based, and completely searchable Nonneoplastic Lesion Atlas just released by the U.S. National Toxicology Program (NTP). The atlas is a much-needed resource with thousands of high-quality, zoomable images and diagnostic guidelines for each rodent lesion. Liver, gallbladder, nervous system, bone marrow, lower urinary tract and skin lesion images, and diagnostic strategies are available now. More organ and biological systems will be added with a total of 22 chapters planned for the completed project. The atlas will be used by the NTP and its many pathology partners to standardize lesion diagnosis, terminology, and the way lesions are recorded. The goal is to improve our understanding of nonneoplastic lesions and the consistency and accuracy of their diagnosis between pathologists and laboratories. The atlas is also a useful training tool for pathology residents and can be used to bolster any organization's own lesion databases. Researchers have free access to this online resource at www.ntp.niehs.nih.gov/nonneoplastic.

Subsite awareness in neuropathology evaluation of National Toxicology Program (NTP) studies: a review of select neuroanatomical structures with their functional significance in rodents

This review article is designed to serve as an introductory guide in neuroanatomy for toxicologic pathologists evaluating general toxicity studies. The article provides an overview of approximately 50 neuroanatomical subsites and their functional significance across 7 transverse sections of the brain. Also reviewed are 3 sections of the spinal cord, cranial and peripheral nerves (trigeminal and sciatic, respectively), and intestinal autonomic ganglia. The review is limited to the evaluation of hematoxylin and eosin-stained tissue sections, as light microscopic evaluation of these sections is an integral part of the first-tier toxicity screening of environmental chemicals, drugs, and other agents. Prominent neuroanatomical sites associated with major neurological disorders are noted. This guide, when used in conjunction with detailed neuroanatomic atlases, may aid in an understanding of the significance of functional neuroanatomy, thereby improving the characterization of neurotoxicity in general toxicity and safety evaluation studies.

Probabilistic risk assessment of exposure to leucomalachite green residues from fish products

To assess the potential risk of human exposure to carcinogenic leucomalachite green (LMG) due to fish consumption, the probabilistic risk assessment was conducted for adolescent, adult and senior adult consumers in Taiwan. The residues of LMG with the mean concentration of 13.378±20.56 μg kg(-1) (BFDA, 2009) in fish was converted into dose, considering fish intake reported for three consumer groups by NAHSIT (1993-1996) and body weight of an average individual of the group. The lifetime average and high 95th percentile dietary intakes of LMG from fish consumption for Taiwanese consumers were estimated at up to 0.0135 and 0.0451 μg kg-bw(-1) day(-1), respectively. Human equivalent dose (HED) of 2.875 mg kg-bw(-1) day(-1) obtained from a lower-bound benchmark dose (BMDL10) in mice by interspecies extrapolation was linearly extrapolated to oral cancer slope factor (CSF) of 0.035 (mgkg-bw(-1)day(-1))(-1) for humans. Although, the assumptions and methods are different, the results of lifetime cancer risk varying from 3×10(-7) to 1.6×10(-6) were comparable to those of margin of exposures (MOEs) varying from 410,000 to 4,800,000. In conclusions, Taiwanese fish consumers with the 95th percentile LADD of LMG have greater risk of liver cancer and need to an action of risk management in Taiwan.

External conditions inversely change the RNA polymerase II elongation rate and density in yeast

Elongation speed is a key parameter in RNA polymerase II (RNA pol II) activity. It affects the transcription rate, while it is conditioned by the physicochemical environment it works in at the same time. For instance, it is well-known that temperature affects the biochemical reactions rates. Therefore in free-living organisms that are able to grow at various environmental temperatures, such as the yeast Saccharomyces cerevisiae, evolution should have not only shaped the structural and functional properties of this key enzyme, but should have also provided mechanisms and pathways to adapt its activity to the optimal performance required. We studied the changes in RNA pol II elongation speed caused by alternations in growth temperature in yeast to find that they strictly follow the Arrhenius equation, and that they also provoke an almost inverse proportional change in RNA pol II density within the optimal growth temperature range (26-37 °C). Moreover, we discovered that yeast cells control the transcription initiation rate by changing the total amount of available RNA pol II.

Low dose effects and non-monotonic dose responses for endocrine active chemicals: science to practice workshop: workshop summary

A workshop was held in Berlin September 12-14th 2012 to assess the state of the science of the data supporting low dose effects and non-monotonic dose responses ("low dose hypothesis") for chemicals with endocrine activity (endocrine disrupting chemicals or EDCs). This workshop consisted of lectures to present the current state of the science of EDC action and also the risk assessment process. These lectures were followed by breakout sessions to integrate scientists from various backgrounds to discuss in an open and unbiased manner the data supporting the "low dose hypothesis". While no consensus was reached the robust discussions were helpful to inform both basic scientists and risk assessors on all the issues. There were a number of important ideas developed to help continue the discussion and improve communication over the next few years.

The STEP (Safety and Toxicity of Excipients for Paediatrics) database: part 2 - the pilot version

The screening and careful selection of excipients is a critical step in paediatric formulation development as certain excipients acceptable in adult formulations, may not be appropriate for paediatric use. While there is extensive toxicity data that could help in better understanding and highlighting the gaps in toxicity studies, the data are often scattered around the information sources and saddled with incompatible data types and formats. This paper is the second in a series that presents the update on the Safety and Toxicity of Excipients for Paediatrics ("STEP") database being developed by Eu-US PFIs, and describes the architecture data fields and functions of the database. The STEP database is a user designed resource that compiles the safety and toxicity data of excipients that is scattered over various sources and presents it in one freely accessible source. Currently, in the pilot database data from over 2000 references/10 excipients presenting preclinical, clinical, regulatory information and toxicological reviews, with references and source links. The STEP database allows searching "FOR" excipients and "BY" excipients. This dual nature of the STEP database, in which toxicity and safety information can be searched in both directions, makes it unique from existing sources. If the pilot is successful, the aim is to increase the number of excipients in the existing database so that a database large enough to be of practical research use will be available. It is anticipated that this source will prove to be a useful platform for data management and data exchange of excipient safety information.

Kinesin-5: cross-bridging mechanism to targeted clinical therapy

Kinesin motor proteins comprise an ATPase superfamily that works hand in hand with microtubules in every eukaryote. The mitotic kinesins, by virtue of their potential therapeutic role in cancerous cells, have been a major focus of research for the past 28 years since the discovery of the canonical Kinesin-1 heavy chain. Perhaps the simplest player in mitotic spindle assembly, Kinesin-5 (also known as Kif11, Eg5, or kinesin spindle protein, KSP) is a plus-end-directed motor localized to interpolar spindle microtubules and to the spindle poles. Comprised of a homotetramer complex, its function primarily is to slide anti-parallel microtubules apart from one another. Based on multi-faceted analyses of this motor from numerous laboratories over the years, we have learned a great deal about the function of this motor at the atomic level for catalysis and as an integrated element of the cytoskeleton. These data have, in turn, informed the function of motile kinesins on the whole, as well as spearheaded integrative models of the mitotic apparatus in particular and regulation of the microtubule cytoskeleton in general. We review what is known about how this nanomotor works, its place inside the cytoskeleton of cells, and its small-molecule inhibitors that provide a toolbox for understanding motor function and for anticancer treatment in the clinic.

A systematic review of Bisphenol A "low dose" studies in the context of human exposure: a case for establishing standards for reporting "low-dose" effects of chemicals

Human exposure to the chemical Bisphenol A is almost ubiquitous in surveyed industrialized societies. Structural features similar to estrogen confer the ability of Bisphenol A (BPA) to bind estrogen receptors, giving BPA membership in the group of environmental pollutants called endocrine disruptors. References by scientists, the media, political entities, and non-governmental organizations to many toxicity studies as "low dose" has led to the belief that exposure levels in these studies are similar to humans, implying that BPA is toxic to humans at current exposures. Through systematic, objective comparison of our current, and a previous compilation of the "low-dose" literature to multiple estimates of human external and internal exposure levels, we found that the "low-dose" moniker describes exposures covering 8-12 orders of magnitude, the majority (91-99% of exposures) being greater than the upper bound of human exposure in the general infant, child and adult U.S. Population. "low dose" is therefore a descriptor without specific meaning regarding human exposure. Where human exposure data are available, for BPA and other environmental chemicals, reference to toxicity study exposures by direct comparison to human exposure would be more informative, more objective, and less susceptible to misunderstanding.

Inhibitors of Bacillus anthracis edema factor

Edema factor (EF) is a calmodulin (CaM)-activated adenylyl cyclase (AC) toxin from Bacillus anthracis that contributes to anthrax pathogenesis. Anthrax is an important medical problem, but treatment of B. anthracis infections is still unsatisfying. Thus, selective EF inhibitors could be valuable drugs in the treatment of anthrax infection, most importantly shock. The catalytic site of EF, the EF/CaM interaction site and allosteric sites constitute potential drug targets. To this end, most efforts have been directed towards targeting the catalytic site. A major challenge in the field is to obtain compounds with high selectivity for AC toxins relative to mammalian membranous ACs (mACs). 3'-(N-methyl)anthraniloyl-2'-deoxyadenosine-5'-triphosphate is the most potent EF inhibitor known so far (Ki, 10nM), but selectivity relative to mACs needs to be improved (currently ~5-50-fold, depending on the specific mAC isoform considered). AC toxin inhibitors can be identified in virtual screening studies based on available EF crystal structures and examined in cellular test systems or at the level of purified toxin using classic radioisotopic or non-radioactive fluorescence assays. Binding of certain MANT-nucleotides to AC toxins elicits large direct fluorescence- or fluorescence resonance energy transfer signals upon interaction with CaM, and these signals can be used to identify toxin inhibitors in competition binding studies. Collectively, potent EF inhibitors are available, but before they can be used clinically, selectivity against mACs must be improved. However, several methodological approaches, complementing each other, are now available to direct the development of potent, selective, orally applicable and clinically useful EF inhibitors.

A new approach to synergize academic and guideline-compliant research: the CLARITY-BPA research program

Recently, medical research has seen a strong push toward translational research, or "bench to bedside" collaborations, that strive to enhance the utility of laboratory science for improving medical treatment. The success of that paradigm supports the potential application of the process to other fields, such as risk assessment. Close collaboration among academic, government, and industry scientists may enhance the translation of scientific findings to regulatory decision making. The National Toxicology Program (NTP), National Institute of Environmental Health Sciences (NIEHS), and U.S. Food and Drug Administration (FDA) developed a consortium-based research program to link more effectively academic and guideline-compliant research. An initial proof-of-concept collaboration, the Consortium Linking Academic and Regulatory Insights on BPA Toxicity (CLARITY-BPA), uses bisphenol A (BPA) as a test chemical. The CLARITY-BPA program combines a core perinatal guideline-compliant 2-year chronic toxicity study with mechanistic studies/endpoints conducted by academic investigators. Twelve extramural grantees were selected by NIEHS through an RFA-based initiative to participate in the overall study design and conduct disease-relevant investigations using tissues and animals from the core study. While the study is expected to contribute to our understanding of potential effects of BPA, it also has ramifications beyond this specific focus. Through CLARITY-BPA, NIEHS has established an unprecedented level of collaboration among extramural grantees and regulatory researchers. By drawing upon the strengths of academic and regulatory expertise and research approaches, CLARITY-BPA represents a potential new model for filling knowledge gaps, enhancing quality control, informing chemical risk assessment, and identifying new methods or endpoints for regulatory hazard assessments.

Gender differences in the incidence of background and chemically induced primary pulmonary neoplasms in B6C3F1 mice: a retrospective analysis of the National Toxicology Program (NTP) carcinogenicity bioassays

The National Toxicology Program (NTP) database of technical reports on carcinogenicity bioassays has been interrogated for the incidence of primary pulmonary neoplasms in B6C3F1 mice. A total of 170 study reports were selected, from studies that completed the in-life phase during 1983-2007, which included neoplasm incidence data for 180 control groups comprising both male and female mice. The incidence (median and inter-quartile range) of males with alveolar/bronchiolar adenoma was 16% (12-20%), and for females it was 5% (2-8%); the incidence of males with alveolar/bronchiolar carcinoma was 8% (4-12%), and for females it was 2% (0-4%); and the incidence of males with combined alveolar/bronchiolar adenoma or carcinoma was 24% (18-30%), and for females it was 8% (6-12%). Comparing the incidence of animals bearing these lesions on a per study basis showed the median incidence in males to be 3.0-fold, 2.0-fold, and 2.8-fold higher than in females. The incidence of other primary pulmonary neoplasms was <10% of the alveolar/bronchiolar neoplasms. Comparison of gender-specific response to lung tumorigens showed that the increase in incidence of tumors above control levels was greater in females than in males.

Impact of non-thermal plasma treatment on MAPK signaling pathways of human immune cell lines

In the field of wound healing research non-thermal plasma (NTP) increasingly draws attention. Next to its intensely studied antibacterial effects, some studies already showed stimulating effects on eukaryotic cells. This promises a unique potential in healing of chronic wounds, where effective therapies are urgently needed. Immune cells do play an important part in the process of wound healing and their reaction to NTP treatment has yet been rarely examined. Here, we studied the impact of NTP treatment using the kinpen on apoptotic and proliferative cell signaling pathways of two human immune cell lines, the CD4(+)T helper cell line Jurkat and the monocyte cell line THP-1. Depending on NTP treatment time the number of apoptotic cells increased in both investigated cell types according to a caspase 3 assay. Western blot analysis pointed out that plasma treatment activated pro-apoptotic signaling proteins like p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun N-terminal kinase 1 and 2 (JNK 1/2) in both cell types. Stronger signals were detected in Jurkat cells at comparable plasma treatment times. Intriguingly, exposure of Jurkat and THP-1 cells to plasma also activated the pro-proliferative signaling molecules extracellular signal-regulated kinase 1/2 (ERK 1/2) and MAPK/ERK kinase 1 and 2 (MEK 1/2). In contrast to Jurkat cells, the anti-apoptotic heat shock protein 27 (HSP27) was activated in THP-1 cells after plasma treatment, indicating a possible mechanism how THP-1 cells may reduce programmed cell death. In conclusion, several signaling cascades were activated in the examined immune cell lines after NTP treatment and in THP-1 monocytes a possible defense mechanism against plasma impacts could be revealed. Therefore, plasma might be a treatment option for wound healing.

Polychlorinated biphenyl 153 is a diet-dependent obesogen that worsens nonalcoholic fatty liver disease in male C57BL6/J mice

BACKGROUND

Polychlorinated biphenyls (PCBs) are persistent environmental pollutants that are detectable in the serum of all American adults. Amongst PCB congeners, PCB 153 has the highest serum level. PCBs have been dose-dependently associated with obesity, metabolic syndrome and nonalcoholic fatty liver disease (NAFLD) in epidemiological studies.

OBJECTIVE

The purpose of this study is to determine mechanisms by which PCB 153 worsens diet-induced obesity and NAFLD in male mice fed a high-fat diet (HFD).

METHODS

Male C57BL6/J mice were fed either control or 42% milk fat diet for 12 weeks with or without PCB 153 coexposure (50 mg/kg ip ×4). Glucose tolerance test was performed, and plasma and tissues were obtained at necropsy for measurements of adipocytokine levels, histology and gene expression.

RESULTS

In control diet-fed mice, addition of PCB 153 had minimal effects on any of the measured parameters. However, PCB 153 treatment in high-fat-fed mice was associated with increased visceral adiposity, hepatic steatosis and plasma adipokines including adiponectin, leptin, resistin and plasminogen activator inhibitor-1 levels. Likewise, coexposure reduced expression of hepatic genes implicated in β-oxidation while increasing the expression of genes associated with lipid biosynthesis. Regardless of diet, PCB 153 had no effect on insulin resistance or tumor necrosis factor alpha levels.

CONCLUSION

PCB 153 is an obesogen that exacerbates hepatic steatosis, alters adipocytokines and disrupts normal hepatic lipid metabolism when administered with HFD but not control diet. Because all US adults have been exposed to PCB 153, this particular nutrient-toxicant interaction potentially impacts human obesity/NAFLD.

The burden and outcomes of childhood tuberculosis in Cotonou, Benin

SETTING

The National Tuberculosis Programme (NTP) and the paediatric ward of the General Hospital (GH), Cotonou, Benin.

OBJECTIVE

To describe the burden of tuberculosis (TB), characteristics and outcomes among children treated in Cotonou from 2009 to 2011.

DESIGN

Cross-sectional cohort study consisting of a retrospective record review of all children with TB aged <15 years.

RESULTS

From 2009 to 2011, 182 children with TB were diagnosed and treated (4.5% of total cases), 153 (84%) by the NTP and 29 (16%) by the GH; the latter were not notified to the NTP. The incidence rate of notified TB cases was between 8 and 13 per 100 000 population, and was higher in children aged >5 years. Of 167 children tested, 29% were HIV-positive. Treatment success was 72% overall, with success rates of 86%, 62% and 74%, respectively, among sputum smear-positive, sputum smear-negative and extra-pulmonary patients. Treatment success rates were lower in children with sputum smear-negative TB (62%) and those with HIV infection (58%).

CONCLUSION

The number of children being treated for TB is low, and younger children in particular are underdiagnosed. There is a need to improve the diagnosis of childhood TB, especially among younger children, and to improve treatment outcomes among HIV-TB infected children, with better follow-up and monitoring.

Use of genomic data in risk assessment case study: I. Evaluation of the dibutyl phthalate male reproductive development toxicity data set

A case study was conducted, using dibutyl phthalate (DBP), to explore an approach to using toxicogenomic data in risk assessment. The toxicity and toxicogenomic data sets relative to DBP-related male reproductive developmental outcomes were considered conjointly to derive information about mode and mechanism of action. In this manuscript, we describe the case study evaluation of the toxicological database for DBP, focusing on identifying the full spectrum of male reproductive developmental effects. The data were assessed to 1) evaluate low dose and low incidence findings and 2) identify male reproductive toxicity endpoints without well-established modes of action (MOAs). These efforts led to the characterization of data gaps and research needs for the toxicity and toxicogenomic studies in a risk assessment context. Further, the identification of endpoints with unexplained MOAs in the toxicity data set was useful in the subsequent evaluation of the mechanistic information that the toxicogenomic data set evaluation could provide. The extensive analysis of the toxicology data set within the MOA context provided a resource of information for DBP in attempts to hypothesize MOAs (for endpoints without a well-established MOA) and to phenotypically anchor toxicogenomic and other mechanistic data both to toxicity endpoints and to available toxicogenomic data. This case study serves as an example of the steps that can be taken to develop a toxicological data source for a risk assessment, both in general and especially for risk assessments that include toxicogenomic data.