1: Toxicol Sci. 2009 Mar;108(1):110-23. Epub 2009 Jan 13. Links
N,N,-diethyl-m-toluamide (DEET) suppresses humoral immunological function in B6C3F1 mice.
Keil DE, McGuinn WD, Dudley AC, EuDaly JG, Gilkeson GS, Peden-Adams MM.
Clinical Laboratory Sciences, University of Nevada-Las Vegas, Las Vegas, Nevada 89154, USA. deborah.keil@unlv.edu

N,N-diethyl-meta-toluamide (DEET) is a particularly effective broad-spectrum insect repellent used commonly in recreational, occupational and military environments. Due to its widespread use and suggested link to Gulf War Illness, this study examined the immunotoxicity of DEET. Adult female B6C3F1 mice were injected sc for 14 days with DEET at 0, 7.7, 15.5, 31, or 62 mg/kg/day. Due to differences in the dermal absorption of DEET between mice and humans, this study eliminated this confounding factor by utilizing sc injection and measured circulating blood levels of DEET to assess bioavailability from sc administration. Effects on lymphocyte proliferation, natural killer cell activity, thymus and spleen weight and cellularity, the antibody plaque-forming cell (PFC) response, and thymic and splenic CD4/CD8 lymphocyte subpopulations were assessed 24 h after the last dose. No effect was observed in lymphocyte proliferation, natural killer cell activity, thymic weight, splenic weight, thymic cellularity, or splenic cellularity. Significant decreases were observed in the percentage of splenic CD4-/CD8- and CD4+/CD8- lymphocytes but only at the 62 mg DEET/kg/day treatment level and not in absolute numbers of these cells types. Additionally, significant decreases in the antibody PFC response were observed following treatment with 15.5, 31, or 62 mg DEET/kg/day. Pharmacokinetic (PK) data from the current study indicate 95% bioavailability of the administered dose. Therefore, it is likely that DEET exposure ranges applied in this study are comparable to currently reported occupational usage. Together, the evidence for immunosuppression and available PK data suggest a potential human health risk associated with DEET in the occupational or military environments assuming similar sensitivity between human and rodent responses.

PMID: 19141786 [PubMed - in process]

1: Behav Brain Res. 2009 Feb 11;197(2):301-10. Epub 2008 Aug 29. Links
Repeated stress in combination with pyridostigmine Part I: long-term behavioural consequences.
Lamproglou I, Barbier L, Diserbo M, Fauvelle F, Fauquette W, Amourette C.
Service d'Oncologie Radiothérapique, Hôpital de la Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75651 Paris Cedex 13, France. ilamprogl@aol.com

Since their return from the first Persian Gulf War, some veterans have complained of a variety of symptoms that were designated as "Gulf War Illness" (GWI). Among other factors, pyridostigmine, used as a prophylaxis treatment against intoxication by nerve agents, has been proposed by many authors as a cause of late social and/or cognitive dysfunction related to GWI. One of the hypotheses placed to explain these behavioural disorders is that operational stress has modified the side effects of pyridostigmine given to soldiers. In an attempt to establish an experimental model of GWI to evaluate the long-term behavioural effects of pyridostigmine administered in stressful conditions, we have developed a new model of repeated stress based on the pole-climbing avoidance technique. We used it to evaluate the effects of pyridostigmine treatment combined to repeated stress over the months following the end of the treatment. We observed that this stress induces impulsiveness and aggressiveness in adult male rat. Moreover, pyridostigmine treatment administered daily 30 min before each stressful session amplifies these behavioural disorders and induces long-term learning dysfunction and slight but significant decrease in phosphocholine level in hippocampus. This suggests that repeated administration of pyridostigmine combined to pole-climbing avoidance (PCA) stress conditions can induce adverse effects in rat central nervous system.

PMID: 18793677 [PubMed - indexed for MEDLINE]

1: Behav Brain Res. 2009 Feb 11;197(2):292-300. Epub 2008 Aug 29. Links
Repeated stress in combination with pyridostigmine Part II: changes in cerebral gene expression.
Barbier L, Diserbo M, Lamproglou I, Amourette C, Peinnequin A, Fauquette W.
Department of Radiobiology and Radiopathology, Centre de Recherches Emile Pardé, 24, Avenue des Maquis du Grésivaudan, BP87-38700 La Tronche Cedex, France. laure barbier@hotmail.fr

Organophosphates (OP) represent a potential threat in terrorism or during military conflicts. Due to its faculty to protect cholinesterase (ChE) activity against irreversible inactivation by OP, pyridostigmine bromide (PB) was used as a prophylaxis treatment during the first Persian Gulf War. To explain dysfunctions reported by Gulf War Veterans (GWV), it was suggested a potentiation of the operational stress effects by PB given to soldiers. Our companion paper (see part 1 in the same journal issue) describes that PB treatment administered in repeated stress conditions results in long-term perturbations of learning and social behaviour. The present paper examines, in adult male Wistar rats, consequences of the association of repeated stress and PB treatment on gene expression in hypothalamus and hippocampus. PB treatment (1.5 mg/kg/day) was orally administered 30 min before each stress session to inhibit 40% of blood ChE as recommended by NATO. 10 days of stress alone induce a decrease in hypothalamic Il-1alpha expression. Treatment with PB alone increases mineralocorticoid receptor expression in hypothalamus which means that PB may thus modify stress perception by animals. Stressed-PB animals showed increase in hippocampal expression of BDNF, TrkB and CamKIIalpha, three genes implicated in memory development. As a supplement to previous studies showing behavioural and biochemical effects of the association of stress with PB, our data reveal that behavioural effects of this association may be linked with genomic changes in hippocampus. Mechanisms underlying these modifications and their link with memory disturbances reported by GWV remain to be further determined.

PMID: 18796314 [PubMed - indexed for MEDLINE]

1: Autoimmun Rev. 2008 Oct;8(1):52-5. Epub 2008 Aug 24. Links
Chronic fatigue syndrome with autoantibodies--the result of an augmented adjuvant effect of hepatitis-B vaccine and silicone implant.
Nancy AL, Shoenfeld Y.
Center for Autoimmune Diseases, Department of Medicine B, Sheba Medical Center, Tel-Hashomer, Israel.

BACKGROUND: Chronic fatigue syndrome (CFS) that defines by prolonged fatigue and other manifestations, was recently integrated into a spectrum of central sensitivity syndromes including several diseases as fibromylagia. CFS etiology is multi-factorial commonly triggered by infectious agents. Vaccines, induce an immune response similarly to infections, and may trigger just like infections autoimmune diseases, CFS and fibromyalgia. Furthermore vaccines contain an adjuvant which enhances their immune stimulation. CASE PRESENTATION: A 56-year-old woman was diagnosed with CFS accompanied by fibromyalgia, demyelination and autoantibodies. Her illness begun following the 2nd dose of hepatitis-B vaccine, and was aggravated by the 3rd vaccination. She underwent silicone breast implantation 6 years before vaccination with no adverse events. However, between the 2nd and 3rd vaccination she suffered a breast injury with local inflammation. Upon explanation of her breast implants silicone leak was observed. DISCUSSION: Vaccines have been reported to precede CFS mainly following exposure to multiple vaccinations (e.g. the Gulf war syndrome), or as an adverse response to the vaccine adjuvant (e.g. the macrophagic myofasciitis syndrome). Silicone is considered an adjuvant to the immune system, and may induce "the adjuvant disease". Silicone implant, especially silicone leak relationship with autoimmunity and CFS has been the focus of considerable debates. CONCLUSION: Our patient illness started following hepatitis-B vaccine, suggesting that it was caused or accelerated by vaccination. In parallel to vaccination our patient suffered from breast injury, which might represent the time of silicone leak. The exposure to the adjuvant, silicone, might have augmented her immune response to the vaccine. To the best of our knowledge this is the first case of combined adverse effect to vaccine and silicone. Vaccine safety in individuals with silicone implants requires further studies.

PMID: 18725327 [PubMed - in process]

1: Med Hypotheses. 2009 Feb;72(2):135-9. Epub 2008 Nov 11. Links
A role for the body burden of aluminium in vaccine-associated macrophagic myofasciitis and chronic fatigue syndrome.
Exley C, Swarbrick L, Gherardi RK, Authier FJ.
Birchall Centre for Inorganic Chemistry and Materials Science, Keele University, Staffordshire ST5 5BG, UK. c.exley@chem.keele.ac.uk

Macrophagic myofasciitis and chronic fatigue syndrome are severely disabling conditions which may be caused by adverse reactions to aluminium-containing adjuvants in vaccines. While a little is known of disease aetiology both conditions are characterised by an aberrant immune response, have a number of prominent symptoms in common and are coincident in many individuals. Herein, we have described a case of vaccine-associated chronic fatigue syndrome and macrophagic myofasciitis in an individual demonstrating aluminium overload. This is the first report linking the latter with either of these two conditions and the possibility is considered that the coincident aluminium overload contributed significantly to the severity of these conditions in this individual. This case has highlighted potential dangers associated with aluminium-containing adjuvants and we have elucidated a possible mechanism whereby vaccination involving aluminium-containing adjuvants could trigger the cascade of immunological events which are associated with autoimmune conditions including chronic fatigue syndrome and macrophagic myofasciitis.

PMID: 19004564 [PubMed - in process]

Biochimie. 2009 Mar 23. [Epub ahead of print] Links

Dna methylation during depleted uranium-induced leukemia.
Miller AC, Stewart M, Rivas R.
Scientific Research Department, Armed Forces Radiobiology Research Institute (AFRRI), Uniformed Services University, Bethesda, MD 20889-5603 USA.

OBJECTIVES: The radioactive heavy metal depleted uranium (DU) is used in kinetic-energy penetrators in military applications. The objective of this study was to determine involvement of DNA methylation in DU-induced leukemia. METHODS: Methylation was measured by direct analysis of 5-methylcytosine content of spleen DNA in DU leukemic mice. RESULTS: Spleen hypomethylation occurred during DU-induced leukemogenesis (chronic internal DU exposure). Aberrant gene transcription was also detected. CONCLUSIONS: Epigenetic mechanisms are implicated in DU-induced leukemia. These data are evidence of aberrant DNA hypomethylation being associated with DU leukemogenesis.

PMID: 19324073 [PubMed - as supplied by publisher]

1: Health Phys. 2009 Apr;96(4):483-92. Links
Acute toxicity of subcutaneously administered depleted uranium and the effects of CBMIDA in the simulated wounds of rats.
Fukuda S, Ikeda M, Nakamura M, Yan X, Xie Y.
Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences, Chiba 263-8555, Japan. s_fukuda@nirs.go.jp

We examined the acute toxicity of depleted uranium (DU) after subcutaneous injection as a simulated wound model (experiment I), and the effects of a chelating agent, catechol-3,6-bis(methyleiminodiacetic acid) (CBMIDA), on the removal and damages caused by uranium by local treatment for wounds in rats (experiment II). Experiment I: To examine the initial behavior and toxicity of uranium of different chemical forms, male Wistar rats were subcutaneously injected with 4 and 16 mg kg-1 DU in a solution of pH 1 and 7. The rats were killed 1, 3, 6, and 24 h after DU injection. The DU (pH 1) injection site on the skin was altered markedly by acid burn, and the chemical action of uranium compared with that of DU (pH 7). After the injection of 4 mg kg-1 DU (pH 1), about 60% of the uranium was retained 1-3 h at the injected sites and then decreased to 16% at 24 h. However, the concentration of uranium in the injected site after 16 mg kg-1 DU (pH 1) injection did not change significantly. Urinary excretion rates of uranium (pH 1) increased in a time-independent manner after the injection. Depositions of uranium in the liver, kidneys and femur were found at 1 h after DU injection, and the results of serum and urinary examinations indicated that severe damage in the organs, including the kidney, was induced. The results of the DU (pH 7) were useful for estimating the chemical toxicity of uranium. Experiment II: The effects of CBMIDA by local treatment for wounds with DU were examined. CBMIDA (480 mg kg-1) was infused into the DU-injected site 0, 10, 30, 60, 120 min, and 24 h after the subcutaneous injection of 4 mg kg-1 DU (pH 1 and 7). The uranium at the injected sites decreased to 4-17% of that at 24 h in the DU (pH 1) group without CBMIDA treatment in experiment I, when it was administered within 120 min after DU injection. In addition, CBMIDA had excellent efficacy in excreting the uranium in urine and feces and decreasing the concentrations of uranium in the kidneys and femur. However, there were no distinct effects of CBMIDA for DU (pH 7). In conclusion, the results indicated that the subcutaneous injected uranium acutely induced severe damage in the DU-injected sites and organs by chemical toxicity within a very short time after DU intake, despite the chemical forms of uranium used, and the local treatment of CBMIDA for wounds contaminated with DU was effective in decreasing the acute toxicity of uranium if carried out within 120 min after DU administration.

PMID: 19276709 [PubMed - indexed for MEDLINE]

J Toxicol Environ Health A. 2009;72(6):410-27. Links

Two-generation reproductive toxicity study of implanted depleted uranium (DU) in CD rats.
Arfsten DP, Still KR, Wilfong ER, Johnson EW, McInturf SM, Eggers JS, Schaeffer DJ, Bekkedal MY.
Navy Drug Screening Laboratory, Naval Air Station Jacksonville, Florida 32212-0113, USA. darryl.arfsten@med.navy.mil

Depleted uranium (DU) munitions and armor plating have been used in several conflicts over the last 17 yr, including the Persian Gulf War and the Iraq War. Because of its effectiveness and availability, DU will continue to be used in military applications into the foreseeable future. There is much controversy over the use of DU in weapons and equipment because of its potential radiological and toxic hazards, and there is concern over the chronic adverse health effects of embedded DU shrapnel in war veterans and bystanders. This study evaluated the effects of long-term implantation of DU on the reproductive success of F0 generation adults and development and survival of subsequent F1 and F2 generations in a two-generation reproductive toxicity study. F0 generation Sprague-Dawley rats, 8 wk of age, were surgically implanted with 0, 4, 8, 12, or 20 DU pellets (1 x 2 mm). Inert implant control animals were implanted with 12 or 20 tantallum (Ta) pellets. The F0 generation was then mated at 120 d post DU implantation. In the F0 generation, when measured on postimplantation d 27 and 117, uranium was present in the urine of DU-implanted animals in a dose-dependent manner. F0 reproductive success was similar across treatment groups and the maternal retrieval test revealed no changes in maternal behavior. DU implantation exerted no effect on the survival, health, or well-being of the F0 generation. Necropsy results of F0 animals were negative with the exception of a marked inflammatory response surrounding the implanted DU pellets. For the F1 generation, measures of F1 development through postnatal day (PND) 20 were unremarkable and no gross abnormalities were observed in F1 offspring. No uranium was detected in whole-body homogenates of PND 4 or PND 20 pups. Necropsy findings of F1 PND 20 pups were negative and no instances of ribcage malformation were observed in F1 PND 20 pups. Body weight and body weight gain of F1 rats through PND 120 were similar across treatment groups. Eight of 414 F1 animals observed from PND 20 to 120 died of unknown causes; 7 were from litters of DU-implanted F0 mating pairs. F1 mating success at 10 wk of age was an overall 70% compared with 91% for F0 mating pairs. Mating success was similar between F1 animals derived from DU-implanted F0 adults and those derived from F0 implant control adults suggesting that the comparatively low mating success was not due to F1 DU exposure. The gestational index of F1 animals derived from mid-dose F0 mating pairs was found to be lower compared with F1 controls. The average gestation duration of F1 animals derived from high-dose F0 mating pairs was found to be significantly longer than F1 controls. F1 sperm motility analyses did not differ among experimental groups and no gross abnormalities were identified at necropsy among surviving F1 animals at PND 120. Histopathology of kidneys, spleen, thymus, bone marrow, ovaries, and testes of F1 high-dose animals did not differ from F1 controls. F1 high-dose females had significantly higher mean relative liver and heart weights compared with F1 controls; the biological relevance of this finding could not be determined. For the F2 generation, measures of F2 development through PND 20 were unremarkable and no gross abnormalities were observed in F2 offspring. Necropsy findings of F2 PND 20 pups were negative and no instances of ribcage malformation were observed in F2 PND 20 pups. Body weight and body weight gain of F2 rats through PND 90 were similar across treatment groups. Mean relative heart weights of males derived from high-dose F0 parents were significantly lower compared with F2 controls. Sperm motility and concentration analysis of F2 males at PND 90 were similar across F2 groups. Overall, the consistent absence of positive findings in this study seems to suggest that DU is not a significant reproductive or developmental hazard, particularly when one considers that mid- and high-dose rats were implanted with the equivalent of 0.3 and 0.5 lb of DU in a 70-kg human, respectively. However, the findings that seven of eight F1 adults that died postweaning were from DU-implanted F0 mating pairs, and that mean relative heart weights were elevated in high-dose F1 and F2 pups, suggest conservatism is warranted in characterizing the reproductive and teratogenic hazards of embedded DU until further studies are completed.

PMID: 19199148 [PubMed - indexed for MEDLINE]

Toxicology. 2009 Apr 5;258(1):1-9. Epub 2008 Dec 31. Links

Different pattern of brain pro-/anti-oxidant activity between depleted and enriched uranium in chronically exposed rats.
Lestaevel P, Romero E, Dhieux B, Ben Soussan H, Berradi H, Dublineau I, Voisin P, Gourmelon P.
Institut de Radioprotection et de Sûreté Nucléaire, Direction de la RadioProtection de l'Homme, Service de Radiobiologie et d'Epidémiologie, Laboratoire de RadioToxicologie Expérimentale. IRSN, B.P. n degrees 17, F 92262 Fontenay-aux-Roses Cedex, France.

Uranium is not only a heavy metal but also an alpha particle emitter. The main toxicity of uranium is expected to be due to chemiotoxicity rather than to radiotoxicity. Some studies have demonstrated that uranium induced some neurological disturbances, but without clear explanations. A possible mechanism of this neurotoxicity could be the oxidative stress induced by reactive oxygen species imbalance. The aim of the present study was to determine whether a chronic ingestion of uranium induced anti-oxidative defence mechanisms in the brain of rats. Rats received depleted (DU) or 4% enriched (EU) uranyl nitrate in the drinking water at 2mg(-1)kg(-1)day(-1) for 9 months. Cerebral cortex analyses were made by measuring mRNA and protein levels and enzymatic activities. Lipid peroxidation, an oxidative stress marker, was significantly enhanced after EU exposure, but not after DU. The gene expression or activity of the main antioxidant enzymes, i.e. superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), increased significantly after chronic exposure to DU. On the contrary, oral EU administration induced a decrease of these antioxidant enzymes. The NO-ergic pathway was almost not perturbed by DU or EU exposure. Finally, DU exposure increased significantly the transporters (Divalent-Metal-Transporter1; DMT1), the storage molecule (ferritin) and the ferroxidase enzyme (ceruloplasmin), but not EU. These results illustrate that oxidative stress plays a key role in the mechanism of uranium neurotoxicity. They showed that chronic exposure to DU, but not EU, seems to induce an increase of several antioxidant agents in order to counteract the oxidative stress. Finally, these results demonstrate the importance of the double toxicity, chemical and radiological, of uranium.

PMID: 19154773 [PubMed - in process]

Med Sci Monit. 2009 Mar;15(3):RA75-90. Links

Current opinion on the science of organophosphate pesticides and toxic stress: a systematic review.
Soltaninejad K, Abdollahi M.
Laboratory of Forensic Toxicology, Legal Medicine Organization of Iran, Tehran, Iran.

The aim of this article is to provide a brief review of the current status of our knowledge related to organophosphates (OPs) and oxidative stress. For this purpose, we performed a systematic review on the literatures using Pubmed and Scopus databases without date limitation. A total of 127 articles including 112 experimental and 15 human studies were found relevant and reviewed. Data were categorized according to experimental and clinical studies. Occurrence of cell membrane lipid peroxidation, alteration in the levels of total antioxidant capacity, total thiol molecules, and protective effects of natural and synthetic antioxidants against OP-induced histopathological and biochemical alterations are the most important evidences for involvement of oxidative stress in OP-induced toxicity. It is concluded that evaluation of blood oxidative stress parameters can be useful for monitoring exposed people. Supplementing of people in exposure to OPs with potent antioxidants such as vitamin E and C is recommended. Much human studies with higher sample size and better exclusion of biasing factors are still needed.

PMID: 19247260 [PubMed - in process]

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