Nano-risk Science: application of toxicogenomics in an adverse outcome pathway framework for risk assessment of multi-walled carbon nanotubes

BACKGROUND: A diverse class of engineered nanomaterials (ENMs) exhibiting a wide array of physical-chemical properties that are associated with toxicological effects in experimental animals is in commercial use. However, an integrated framework for human health risk assessment (HHRA) of ENMs has yet to be established. Rodent 2-year cancer bioassays, clinical chemistry, and histopathological endpoints are still considered the ‘gold standard’ for detecting substance-induced toxicity in animal models. However, the use of data derived from alternative toxicological tools, such as genome-wide expression profiling and in vitro high-throughput assays, are gaining acceptance by the regulatory community for hazard identification and for understanding the underlying mode-of-action. Here, we conducted a case study to evaluate the application of global gene expression data in deriving pathway-based points of departure (PODs) for multi-walled carbon nanotube (MWCNT)-induced lung fibrosis, a non-cancer endpoint of regulatory importance. METHODS: Gene expression profiles from the lungs of mice exposed to three individual MWCNTs with different physical-chemical properties were used within the framework of an adverse outcome pathway (AOP) for lung fibrosis to identify key biological events linking MWCNT exposure to lung fibrosis. Significantly perturbed pathways were categorized along the key events described in the AOP. Benchmark doses (BMDs) were calculated for each perturbed pathway and were used to derive transcriptional BMDs for each MWCNT. RESULTS: Similar biological pathways were perturbed by the different MWCNT types across the doses and post-exposure time points studied. The pathway BMD values showed a time-dependent trend, with lower BMDs for pathways perturbed at the earlier post-exposure time points (24 h, 3d). The transcriptional BMDs were compared to the apical BMDs derived by the National Institute for Occupational Safety and Health (NIOSH) using alveolar septal thickness and fibrotic lesions endpoints. We found that regardless of the type of MWCNT, the BMD values for pathways associated with fibrosis were 14.0–30.4 μg/mouse, which are comparable to the BMDs derived by NIOSH for MWCNT-induced lung fibrotic lesions (21.0–27.1 μg/mouse). CONCLUSIONS: The results demonstrate that transcriptomic data can be used to as an effective mechanism-based method to derive acceptable levels of exposure to nanomaterials in product development when epidemiological data are unavailable. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12989-016-0125-9) contains supplementary material, which is available to authorized users

Concurrent Acquisition of a Single Nucleotide Polymorphism in Diverse Influenza H5N1 Clade 2.2 Sub-clades

Highly pathogenic Influenza A H5N1 was first identified in Guangdong Province in 1996, followed by human cases in Hong Kong in 1997. The number of confirmed human cases now exceeds 300, and the associated Case Fatality Rate exceeds 60%. The genetic diversity of the serotype continues to increase. Four distinct clades or sub-clades have been linked to human cases. The gradual genetic changes identified in the sub-clades have been attributed to copy errors by viral encoded polymerases that lack an editing function, thereby resulting in antigenic drift. We report here the concurrent acquisition of the same polymorphism by multiple, genetically distinct, clade 2.2 sub-clades in Egypt, Russia, and Ghana. These changes are not easily explained by the current theory of “random mutation” through copy error, and are more easily explained by recombination with a common source. This conclusion is supported by additional polymorphisms shared by clade 2.2 isolates in Egypt and Germany

Independent Ion Migration in Suspensions of Strongly Interacting Charged Colloidal Spheres

We report on sytematic measurements of the low frequency conductivity in aequous supensions of highly charged colloidal spheres. System preparation in a closed tubing system results in precisely controlled number densities between 1E16/m3 and 1E19/m^3 (packing fractions between 1E-7 and 1E-2) and electrolyte concentrations between 1E-7 and 1E-3 mol/l. Due to long ranged Coulomb repulsion some of the systems show a pronounced fluid or crystalline order. Under deionized conditions we find s to depend linearily on the packing fraction with no detectable influence of the phase transitions. Further at constant packing fraction s increases sublinearily with increasing number of dissociable surface groups N. As a function of c the conductivity shows pronounced differences depending on the kind of electrolyte used. We propose a simple yet powerful model based on independent migration of all species present and additivity of the respective conductivity contributions. It takes account of small ion macro-ion interactions in terms of an effectivly transported charge. The model successfully describes our qualitatively complex experimental observations. It further facilitates quantitative estimates of conductivity over a wide range of particle and experimental parameters.Comment: 32 pages, 17 figures, 2 tables, Accepted by Physical Review

Aggregation of Single Nucleotide Polymorphisms in a Human H5N1 Clade 2.2 Hemagglutinin

The evolution of H5N1 has attracted significant interest 1-4 due to linkages with avian 5,6 and human infections 7,8. The basic tenets of influenza genetics 9 attribute genetic drift to replication errors caused by a polymerase complex that lacks a proof reading function. However, recent analysis 10 of swine influenza genes identifies regions copied with absolute fidelity for more than 25 years. In addition, polymorphism tracing of clade 2.2 H5N1 single nucleotide polymorphisms identify concurrent acquisition 11 of the same polymorphism onto multiple genetic backgrounds in widely dispersed geographical locations. Here we show the aggregation of regional clade 2.2 polymorphisms from Germany, Egypt, and sub-Sahara Africa onto a human Nigerian H5N1 hemagglutinin (HA), implicating recombination in the dispersal and aggregation of single nucleotide polymorphisms from closely related genomes

Multicentre observational study of adherence to Sepsis Six guidelines in emergency general surgery

Background Evidence-based interventions may reduce mortality in surgical patients. This study documented the prevalence of sepsis, adherence to guidelines in its management, and timing of source control in general surgical patients presenting as an emergency. Methods Patients aged 16 years or more presenting with emergency general surgery problems were identified over a 7-day period and then screened for sepsis compliance (using the Sepsis Six standards, devised for severe sepsis) and the timing of source control (whether radiological or surgical). Exploratory analyses examined associations between the mode (emergency department or general practitioner) and time of admission, adherence to the sepsis guidelines, and outcomes (complications or death within 30 days). Results Of a total of 5067 patients from 97 hospitals across the UK, 911 (18·0 per cent) fulfilled the criteria for sepsis, 165 (3·3 per cent) for severe sepsis and 24 (0·5 per cent) for septic shock. Timely delivery of all Sepsis Six guidelines for patients with severe sepsis was achieved in four patients. For patients with severe sepsis, 17·6–94·5 per cent of individual guidelines within the Sepsis Six were delivered. Oxygen was the criterion most likely to be missed, followed by blood cultures in all sepsis severity categories. Surgery for source control occurred a median of 19·8 (i.q.r. 10·0–35·4) h after diagnosis. Omission of Sepsis Six parameters did not appear to be associated with an increase in morbidity or mortality. Conclusion Although sepsis was common in general surgical patients presenting as an emergency, adherence to severe sepsis guidelines was incomplete in the majority. Despite this, no evidence of harm was apparent

Pattern of Bladder Cancer at University Teaching Hospital, Lusaka, Zambia in the era of HIV Epidemic

Background: Human Immunodeficiency Virus (HIV) is endemic to Zambia and is associated with changes in the patterns of both AIDS and non- AIDS defining cancers. Bladder cancer is one malignancy that has been noted toincrease in the era of HIV/ AIDS epidemic. This study sought to describe the pattern of cancer of the bladder at UTH in the era of HIV/AIDS epidemic in respect with the epidemiological characteristics, prevalence of HIV infection and the histological types of bladder cancer in patients with cancer of the bladder.Patients and Methods: A prospective cross sectional, hospital based study was performed at the University Teaching Hospital (UTH), Lusaka, Zambia, between November 2009 and November 2010. Patients with bladder cancer who presented to the hospital during this period were recruited and  parameters studied included patients demographics, HIV status and pathology of cancer. Data collected was analyzed using SPSS 17.Results: A total of 53 patients with median age of 57.49 years who had histological confirmed bladder cancer were recruited during this one year period. The male to female ratio was 1.3 to 1. Of the 53 patients, HIV infection was found in six patients (11.3 %). Squamous cell carcinoma was the most common histological type (60.4%) followed by Transitional cell carcinoma (30.2%) and adenocarcinoma was least common type (9.4%).Schistosoma infection was found in 14 patients all had SCC. The study found a statistically significant reduction in the mean age of bladder cancer in HIV infected patients.Conclusions: Squamous cell carcinoma is still the most common histological type of bladder cancer in Zambia and it's strongly associated with schistosomia infection. Haematuria remains to be the most common presenting symptom in bladder cancer patients

Pattern of Bladder Cancer at University Teaching Hospital, Lusaka, Zambia in the era of HIV Epidemic

Background: Human Immunodeficiency Virus (HIV) is endemic to Zambia and is associated with changes in the patterns of both AIDS and non- AIDS defining cancers. Bladder cancer is one malignancy that has been noted to increase in the era of HIV/ AIDS epidemic. This study sought to describe the pattern of cancer of the bladder at UTH in the era of HIV/AIDS epidemic in respect with the epidemiological characteristics, prevalence of HIV infection and the histological types of bladder cancer in patients with cancer of the bladder.Patients and Methods: A prospective cross sectional, hospital based study was performed at the University Teaching Hospital (UTH), Lusaka, Zambia, between November 2009 and November 2010. Patients with bladder cancer who presented to the hospital during this period were recruited and parameters studied included patients demographics, HIV status and pathology of cancer. Data collected was analyzed using SPSS 17.Results: A total of 53 patients with median age of 57.49 years who had histological confirmed bladder cancer were recruited during this one year period. The male to female ratio was 1.3 to 1. Of the 53 patients, HIV infection was found in six patients (11.3 %). Squamous cell carcinoma was the most common histological type (60.4%) followed by Transitional cell carcinoma (30.2%) and adenocarcinoma was least common type (9.4%). Schistosoma infection was found in 14 patients all had SCC. The study found a statistically significant reduction in the mean age of bladder cancer in HIV infected patients.Conclusions: Squamous cell carcinoma is still the most common histological type of bladder cancer in Zambia and it's strongly associated with schistosomia infection. Haematuria remains to be the most common presenting symptom in bladder cancer patients.

Aggregation of Single Nucleotide Polymorphisms in a Human H5N1 Clade 2.2 Hemagglutinin

The rapid evolution of the H5N1 serotype of avian influenza has been explained by a mechanism involving the selection of single nucleotide polymorphisms generated by copy errors. The recent emergence of H5N1 Clade 2.2 in fifty countries, offered a unique opportunity to view the acquisition of new polymorphism in these evolving genomes. We analyzed the H5N1 hemagglutinin gene from a fatal human case from Nigeria in 2007. The newly emerged polymorphisms were present in diverse H5N1 isolates from the previous year. The aggregation of these polymorphisms from clade 2.2 sub-clades was not supported by recent random mutations, and was most easily explained by recombination between closely related sequences

The Effects of Cocaine on Different Redox Forms of Cysteine and Homocysteine, and on Labile, Reduced Sulfur in the Rat Plasma Following Active versus Passive Drug Injections

Received: 28 November 2012 / Revised: 19 April 2013 / Accepted: 6 May 2013 / Published online: 16 May 2013 The Author(s) 2013. This article is published with open access at Springerlink.comThe aim of the present studies was to evaluate cocaine-induced changes in the concentrations of different redox forms of cysteine (Cys) and homocysteine (Hcy), and products of anaerobic Cys metabolism, i.e., labile, reduced sulfur (LS) in the rat plasma. The above-mentioned parameters were determined after i.p. acute and subchronic cocaine treatment as well as following i.v. cocaine self-administration using the yoked procedure. Additionally, Cys, Hcy, and LS levels were measured during the 10-day extinction training in rats that underwent i.v. cocaine administration. Acute i.p. cocaine treatment increased the total and protein-bound Hcy contents, decreased LS, and did not change the concentrations of Cys fractions in the rat plasma. In turn, subchronic i.p. cocaine administration significantly increased free Hcy and lowered the total and protein-bound Cys concentrations while LS level was unchanged. Cocaine self-administration enhanced the total and protein-bound Hcy levels, decreased LS content, and did not affect the Cys fractions. On the other hand, yoked cocaine infusions did not alter the concentration of Hcy fractions while decreased the total and protein-bound Cys and LS content. This extinction training resulted in the lack of changes in the examined parameters in rats with a history of cocaine self-administration while in the yoked cocaine group an increase in the plasma free Cys fraction and LS was seen. Our results demonstrate for the first time that cocaine does evoke significant changes in homeostasis of thiol amino acids Cys and Hcy, and in some products of anaerobic Cys metabolism, which are dependent on the way of cocaine administration

Pre-operative bladder irrigation with 1% Povidone iodine in reducing open prostatectomy surgical site infection (SSI) at university teaching hospital, Lusaka

Purpose: The aim of the study is to assess the effectiveness of using preoperative bladder irrigation with 1% povidone iodine in reducing post transvesical prostatectomy surgical site infections. Study design: This was a prospective randomized cohort study with blinding of patients and outcome adjudicator regarding group assignments.Methodology: One hundred and thirty patients were recruited from the waiting list of Urology unit II in the department of surgery during the period between July 2011 to December 2012. The non-probability convenience sampling technique was used. Any consenting patient who presented to the department of surgery for open prostatectomy and fulfills the inclusion criteria was selected. The patients were randomly allocated to each of the two groups. Each group had 65 patients. Patients in the study group had their bladder irrigated with 1% 50cc povidoneiodine which was drained upon opening the bladder followed by enucleating the adenomatous prostate gland. Hemostasis was ensured and a 3 way Foley's catheter inserted via the urethral into the bladder and ballooned appropriately for draining and irrigation. The bladder was sutured in 2 layers using 0 or 1 chromic catgut. In the control group povidone-iodine was not used. Both groups received pre-operative antibiotics 30 minutes before incision and post-operative for 5 days. Pre-operative, intraoperative and post-operative data were collected on a standardized data collection forms. Post-operative irrigation was done for 9 to 12 days after which the catheter was removed as an outpatient. Patients were followed up in the urological clinic at 1 week, 2weeks and at 4 weeks post-operatively to assess whether they had developed surgical site infections according to CDC guidelines. Data was analyzed using SPSS version 16.Results: The patients mean age was 71.1 in the control group and 71.4 in the study group with no statistically significant difference (t=0.318; p=0.75; df=126.89). The overall surgical infection rate was 16.2%. In the control group 15 out of 65 patients (23.1%) developed SSIs. While in the study group 6 out of 65 patients (9.2%) developed SSIs. The difference in the rates of SSI between the two groups was statistically significant (÷²; p<0.05; df=126.89) Escherichia coli was the most predominant organism 13/37 (35%), streptococcus 7/37 (18.9), Citrobacter koseri 5/37 (13.5%), Klebsiella sp 4/37 (10.8%). Escherichia coli, Streptococcus and Citrobacter were sensitive to ciprofloxacin; Pantoea agglomerans was sensitive to ceftazidime while Staphylococcus coagulase was sensitive to imipenem. Enterobacter cloace was resistant to all antibiotics used.Conclusion: The study found that irrigating the bladder with 1% povidone-iodine resulted in significant reduction in post prostatectomy surgical site infection, Escherichia coli as the most common causative organism, reduced morbidity and post-operative hospital stay in the povidone iodine group.Key words: Benign prostatic hyperplasia, transvesical prostatectomy, povidone iodine, surgical site infections