Urinary Pesticide Residual Levels and Acute Respiratory Infections in Children Under 5 Years of Age: Findings From the Offinso North Farm Health Study.

Background: Several environmental factors are associated with the risk of acute lower respiratory infections (ALRIs) and upper respiratory infections (URIs) in children under 5 years of age (YOA). Evidence implicating chemical pesticides remains equivocal. There are also no data on this subject in these children in Ghana. This study investigated the association between urinary pesticide residual levels and the risk for ALRIs/URIs in children under 5 YOA. Methods: The participants for this study were from the Offinso North Farm Health Study, a population-based cross-sectional study. Two hundred and fifty four parents/guardians who had answered affirmatively to the question "Has your child ever accompanied you to the farm?" were interviewed on household socio-demographic and environmental factors, being breastfed, child education, age, gender, and respiratory infection. One hundred fifty children were randomly selected to provide the first void urine. Results: The proportion of children with ALRI was 22.1% and those with URI was 35.8%. We observed a statistically significant exposure-response relation of p,p'-DDE (tertile) with ALRI (1.7-3.2 µg/L urine: prevalence ratio [PR] = 1.22 [1.05-1.70], ⩾3.2 µg/L urine: 1.50 [1.07-3.53] [P-for trend = .0297]). This observation was in children older than two YOA (P-for trend = .0404). Delta-HCH and beta-HCH (2-levels) were significantly associated with ALRI but not URI. The risk of ALRI increased with deltamethrin levels in an exposure-response manner (2.5-9.5 µg/L urine: 2.10 [1.37-3.24], ⩾9.5 µg/L urine: 4.38 [1.87-10.32] [P-for trend = .0011]) and this was also observed in children older than two YOA. Similar observation was noted for URI. Bifenthrin (>0.5 µg/L urine) was positively associated with ALRI and URI whereas permethrin (⩾1.2 µg/L urine) was not associated only with URI. Conclusions: The present study supports the hypothesis that exposure to chemical pesticides is associated with respiratory infections in children under 5 YOA.

Role of Oxidative Stress in Hypersensitivity Reactions to Sulfonamides.

Antimicrobial sulfonamides are important medications. However, their use is associated with major immune-mediated drug hypersensitivity reactions with a rate that ranges from 3% to 4% in the general population. The pathophysiology of sulfa-induced drug hypersensitivity reactions is not well understood, but accumulation of reactive metabolites (sulfamethoxazole [SMX] hydroxylamine [SMX-HA] and SMX N-nitrosamine [SMX-NO]) is thought to be a major factor. These reactive metabolites contribute to the formation of reactive oxygen species (ROS) known to cause cellular damage and induce cell death through apoptosis and necroptosis. ROS can also serve as "danger signals," priming immune cells to mount an immunological reaction. We recruited 26 sulfa-hypersensitive (HS) patients, 19 healthy control subjects, and 6 sulfa-tolerant patients to this study. Peripheral blood monocytes and platelets were isolated from blood samples and analyzed for in vitro cytotoxicity, ROS and carbonyl protein formation, lipid peroxidation, and GSH (glutathione) content after challenge with SMX-HA. When challenged with SMX-HA, cells isolated from sulfa-HS patients exhibited significantly (P ≤ .05) higher cell death, ROS and carbonyl protein formation, and lipid peroxidation. In addition, there was a high correlation between cell death in PBMCs and ROS levels. There was also depletion of GSH and lower GSH/GSSG ratios in peripheral blood mononuclear cells from sulfa-HS patients. The amount of ROS formed was negatively correlated with intracellular GSH content. The data demonstrate a major role for oxidative stress in in vitro cytotoxicity of SMX reactive metabolites and indicate increased vulnerability of cells from sulfa-HS patients to the in vitro challenge.

Respiratory and non-respiratory symptoms associated with pesticide management practices among farmers in Ghana's most important vegetable hub.

The data presented here are from the Offinso North District Farm Health Study (ONFAHS), a population-based cross-sectional study among vegetable farmers in Ghana. The paper addresses knowledge, pesticide handling practices, and protective measures related to pesticide use by self-reported symptoms for 310 adult farmers who completed a comprehensive questionnaire on pesticide management practices and health. In addition, an inventory was prepared using information supplied by pesticide sellers/dealers in this district. We report that cough and wheezing (but not breathlessness) are positively associated with stirring pesticide preparations with bare hands/drinking water while mixing/applying pesticides, and stirring pesticide preparations with bare hands/drinking water/smoking cigarettes while mixing/applying pesticides. There is a significant exposure-response association between the number of precautionary measures practiced while handling pesticides and cough and wheezing but not with breathlessness. We also found unsafe practices to be associated with sexual dysfunction, nervousness, and lack of concentration. The results also suggest a negative association between practice of any precautionary measure when mixing/applying pesticides and sexual dysfunction, nervousness, and lack of concentration. We found that in spite of the fact that farmers have adequate knowledge about the environment and health effects of pesticides, several unhygienic practices are in widespread use, indicating that knowledge is not necessarily always translated in action. Further action is necessary to promote the safe use of pesticides and to replace existing poor management practices among these and other farmers in Ghana.

HIV-1 tat expression and sulphamethoxazole hydroxylamine mediated oxidative stress alter the disulfide proteome in Jurkat T cells.

BACKGROUND: Adverse drug reactions (ADRs) are a significant problem for HIV patients, with the risk of developing ADRs increasing as the infection progresses to AIDS. However, the pathophysiology underlying ADRs remains unknown. Sulphamethoxazole (SMX) via its active metabolite SMX-hydroxlyamine, when used prophylactically for pneumocystis pneumonia in HIV-positive individuals, is responsible for a high incidence of ADRs. We previously demonstrated that the HIV infection and, more specifically, that the HIV-1 Tat protein can exacerbate SMX-HA-mediated ADRs. In the current study, Jurkat T cell lines expressing Tat and its deletion mutants were used to determine the effect of Tat on the thiol proteome in the presence and absence of SMX-HA revealing drug-dependent changes in the disulfide proteome in HIV infected cells. Protein lysates from HIV infected Jurkat T cells and Jurkat T cells stably transfected with HIV Tat and Tat deletion mutants were subjected to quantitative slot blot analysis, western blot analysis and redox 2 dimensional (2D) gel electrophoresis to analyze the effects of SMX-HA on the thiol proteome. RESULTS: Redox 2D gel electrophoresis demonstrated that untreated, Tat-expressing cells contain a number of proteins with oxidized thiols. The most prominent of these protein thiols was identified as peroxiredoxin. The untreated, Tat-expressing cell lines had lower levels of peroxiredoxin compared to the parental Jurkat E6.1 T cell line. Conversely, incubation with SMX-HA led to a 2- to 3-fold increase in thiol protein oxidation as well as a significant reduction in the level of peroxiredoxin in all the cell lines, particularly in the Tat-expressing cell lines. CONCLUSION: SMX-HA is an oxidant capable of inducing the oxidation of reactive protein cysteine thiols, the majority of which formed intermolecular protein bonds. The HIV Tat-expressing cell lines showed greater levels of oxidative stress than the Jurkat E6.1 cell line when treated with SMX-HA. Therefore, the combination of HIV Tat and SMX-HA appears to alter the activity of cellular proteins required for redox homeostasis and thereby accentuate the cytopathic effects associated with HIV infection of T cells that sets the stage for the initiation of an ADR.

Associations between pesticide use and respiratory symptoms: A cross-sectional study in Southern Ghana.

BACKGROUND: Indiscriminate use of pesticides is a common practice amongst farmers in Low and Middle Income Countries (LMIC) across the globe. However, there is little evidence defining whether pesticide use is associated with respiratory symptoms. OBJECTIVES: This cross-sectional study was conducted with 300 vegetable farmers in southern Ghana (Akumadan). Data on pesticide use was collected with an interviewed-administered questionnaire. The concentration of seven organochlorine pesticides and 3 pyrethroid pesticides was assayed in urine collected from a sub-population of 100 vegetable farmers by a gas chromatograph equipped with an electron capture detector (GC-ECD). RESULTS: A statistically significant exposure-response relationship of years per day spent mixing/applying fumigant with wheezing [30-60 days/year: prevalence ratio (PR)=1.80 (95% CI 1.30, 2.50); >60days/year: 3.25 (1.70-6.33), p for trend=0.003] and hours per day spent mixing/applying fumigant with wheezing [1-2h/day: 1.20 (1.02-1.41), 3-5h/day: 1.45 (1.05-1.99), >5h/day: 1.74 (1.07-2.81), p for trend=0.0225]; days per year spent mixing/applying fungicide with wheezing [30-60 days/year: 2.04 (1.31-3.17); >60days/year: 4.16 (1.72-10.08), p for trend=0.0017] and h per day spent mixing/applying fungicide with phlegm production [1-2h/day: 1.25 (1.05-1.47), 3-5h/day: 1.55 (1.11-2.17), >5h/day: 1.93 (1.17-3.19), p for trend=0.0028] and with wheezing [1-2h/day: 1.10 (1.00-1.50), 3-5h/day: 1.20 (1.11-1.72), >5h/day: 1.32 (1.09-2.53), p for trend=0.0088]; h per day spent mixing/applying insecticide with phlegm production [1-2h/day: 1.23 (1.09-1.62), 3-5h/day: 1.51 (1.20-2.58), >5h/day: 1.85 (1.31-4.15), p for trend=0.0387] and wheezing [1-2h/day: 1.22 (1.02-1.46), 3-5h/day: 1.49 (1.04-2.12), >5h/day: 1.81 (1.07-3.08), p for trend=0.0185] were observed. Statistically significant exposure-response association was also observed for a combination of activities that exposes farmers to pesticide with all 3 respiratory symptoms. Furthermore, significant exposure-response associations for 3 organochlorine insecticides: beta-HCH, heptachlor and endosulfan sulfate were noted. CONCLUSIONS: In conclusion, vegetable farmers in Ghana may be at increased risk for respiratory symptoms as a result of exposure to pesticides.

Cultural and socio-economic conditions as factors contributing to chronic stress in sub-Saharan African communities.

Stress is known to contribute to overall health status. Many individuals in sub-Saharan Africa are believed to be stressed about their employment, income, and health. This study aimed to investigate hair cortisol as a biomarker of chronic stress in settlement communities in Kenya. Hair samples were collected from 108 volunteers from settlement communities in Kenya. An enzyme-linked immunosorbent assay technique was used to measure hair cortisol concentrations. In parallel, a health survey was completed. The mean ± SD for the cortisol concentration in the hair of volunteers from the settlement communities in Naivasha was 639 ± 300 ng/g, which was higher than found for a Caucasian reference group (299 ± 110 ng/g; one-way ANOVA, P = 0.0003). There were no differences in hair cortisol concentrations between members of slum settlements adjacent to large floriculture farms in Naivasha (Karagita, Kamere/Kwa Muhia/DCK, and Kasarani) compared with those well-removed from all floriculture in Mogotio (Mogotio and Westlands/Katorongot). However, hair cortisol concentrations were significantly higher in females, divorced volunteers, those who made below minimum wage, and those who reported feeling unsafe collecting water or using sanitation facilities within these 2 settlement groups. We found no evidence for increased chronic stress (measured by hair cortisol content) between members of slum settlements adjacent to versus distant to large floriculture farms. Cultural and socio-economic conditions that prevail in much of sub-Saharan Africa were found to be factors contributing to chronic stress.

Hair cortisol as a biomarker of stress among a first nation in Canada.

BACKGROUND: Cortisol level in hair is increasingly being used as a biomarker of chronic stress. Members of First Nation communities in Canada are experiencing stress related to a higher incidence of chronic diseases, socioeconomic factors, the state of their environment, and cultural oppression. This study aimed to investigate hair cortisol as a biomarker of stress in this population. MATERIALS AND METHODS: Hair samples were collected from the posterior vertex of 55 Walpole Island First Nation (WIFN) volunteers and compared with white volunteers living in and around London, ON, Canada. An enzyme-linked immunosorbent assay technique was used to measure cortisol content in 1 cm of hair, considered to represent 1 month of growth. In parallel, the Perceived Stress Scale (PSS), which measures short-term stress, was also completed. RESULTS: Median hair cortisol level (range) in WIFN volunteers was 177 (93-273) ng/g, significantly higher than the median hair cortisol in the healthy white controls of 116 (26-204) ng/g (P < 0.0001, Mann-Whitney U test). Hair cortisol correlated positively with gender, smoking status, and self-reported diabetes. Unlike hair cortisol, the Perceived Stress Scale did not differentiate between the First Nation and control population. CONCLUSIONS: The increased hair cortisol concentrations among WIFN volunteers compared with volunteers from a non-First Nation community suggests higher levels of chronic stress. The causes for this apparent increased stress are likely due to factors such as socioeconomic and poorer health and are worthy of further evaluation. The results highlight the difference between acute stress measured for short periods of time compared with chronic stress, measured by hair analysis.

Severe bullous hypersensitivity reactions after exposure to carbamazepine in a Han-Chinese child with a positive HLA-B*1502 and negative in vitro toxicity assays: evidence for different pathophysiological mechanisms.

BACKGROUND: Drug hypersensitivity syndrome (DHS) can present in several clinical forms ranging from simple maculopapular skin rash to severe bullous reactions and multi-system dysfunction. Genetic analysis of DHS patients has revealed a striking association between carbamazepine (CBZ)-induced severe bullous reactions, such as Steven-Johnson Syndrome, and toxic epidermal necrolysis in individuals from Southeast Asia who carry a specific HLA allele (HLA-B*1502). This ethnic-specific relationship with a disease phenotype has raised the question of the commonality of the pathogenesis mechanisms of these diseases. The aim of this study was to investigate the genetic and metabolic bases of DHS development to help predict patient susceptibility. METHOD: A case of carbamazepine-induced Steven-Johnson Syndrome reaction in a HLA-B*1502 positive child of Han Chinese origin, a carbamazepine-induced DHS case in a Caucasian patient and 3 healthy controls were investigated. We performed two types of in vitro toxicity assay, the lymphocyte toxicity assay (LTA) and the novel in vitro platelet toxicity assay (iPTA) on cells taken from the Chinese child 3 and 9 months after recovery from the reaction and from two healthy volunteers. We also tested the Caucasian patient, who developed CBZ-induced DHS, 3 months after the reaction. RESULTS: Both LTA and iPTA tests were negative 3 and 9 months after the reaction on samples from the Chinese child whereas the tests were positive in the Caucasian patient. CONCLUSION: These results strongly suggest more than one mechanistic pathway for different CBZ-induced hypersensitivity reactions in patients with different ethnic backgrounds.

Fish consumption in pregnancy and fetal risks of methylmercury toxicity.

QUESTION: Because I practise in a rural area with a large number of lakes, I have patients planning pregnancy who consume relatively large amounts of fish harvested by their families. What should be my advice to them? ANSWER: A recent Motherisk study has shown that fairly commonly these women's mercury levels exceed the threshold level for cognitive effects. Women should not consume excessive amounts of seafood in pregnancy (ie, no more than 2 weekly average size servings). Hair mercury level above 0.3 µg/g indicates a potentially excessive body burden.

Hair methylmercury: a new indication for therapeutic monitoring.

Maternal exposure to methylmercury can adversely affect fetal neurodevelopment. Long-term mercury exposure is best estimated by hair measurement of the metal. The authors analyzed the appropriateness of therapeutic monitoring of hair mercury in women of reproductive age using widely accepted criteria for therapeutic drug monitoring. The analysis reveals that such monitoring can help protect babies from long-term adverse effects, while ensuring appropriate maternal fish consumption.

Global changes in gene regulation demonstrate that unconjugated bilirubin is able to upregulate and activate select components of the endoplasmic reticulum stress response pathway.

Elevated concentrations of unconjugated bilirubin (UCB) are responsible for neonatal jaundice and can eventually lead to kernicterus or death. The molecular mechanism of UCB toxicity is incompletely elucidated. The purpose of this study was to analyze changes in gene regulation mediated by UCB to determine novel pathways that contribute to UCB-mediated toxicity. We employed microarray analysis to determine changes in gene regulation mediated by UCB at both pro- (50 microM) and antioxidant (70 nM) concentrations in Hepa 1c1c7 cells at 1 and 6 h. The changes observed in select genes were validated with qPCR. Using immunoblot analysis, we validated these changes at the protein level for select genes and documented the activation of two proteins involved in the endoplasmic reticulum (ER) stress pathway, eIF2 alpha and PERK. Following treatment with 50 microM UCB, microarray analysis revealed the upregulation of many genes involved in ER stress (ATF3, BiP, CHOP, Dnajb1, and Herp). We demonstrate that upregulation of the proapoptotic transcription factor CHOP results in increased intracellular protein content. It was determined that activation of proteins involved in ER stress was an early event in UCB toxicity as eIF2 alpha and PERK were both phosphorylated and activated by 1 h posttreatment. We also demonstrate that procaspase-12 content, a proposed initiator caspase in ER stress-mediated apoptosis, is decreased by 4 h posttreatment. In conclusion, this study demonstrates that elevated concentrations of UCB (50 microM) are able to activate select components of the ER stress pathway in Hepa 1c1c7 cells, which may contribute to UCB-mediated apoptosis.

Hair mercury levels of women of reproductive age in Ontario, Canada: implications to fetal safety and fish consumption.

OBJECTIVE: To study hair mercury concentrations among women of reproductive age in relation to fish intake in Ontario, Canada. STUDY DESIGN: Three groups were studied: 22 women who had called the Motherisk Program for information on the reproductive safety of consuming fish during pregnancy, a group of Japanese residing in Toronto (n=23) consuming much larger amounts of fish, and a group of Canadian women of reproductive age (n=20) not seeking advice, were studied. Mercury concentrations in hair samples were measured using inductively coupled plasma mass spectrometry. Seafood consumption habits were recorded for each participant. Based on the types of fish consumed and consumption frequencies, the estimated monthly intake of mercury was calculated. Hair mercury concentrations were correlated to both the number of monthly seafood servings and the estimated ingested mercury dose. RESULTS: There were significant correlations between fish servings and hair mercury (Spearman r=0.73, P<.0001) and between amounts of consumed mercury and hair mercury concentrations (Spearman r=0.81, P<.0001). Nearly two thirds of the Motherisk callers, all of the Japanese women, and 15% of the Canadian women of reproductive age had hair mercury above 0.3 microg/g, which was shown recently to be the lowest observable adverse effect level in a large systematic review of all perinatal studies. CONCLUSIONS: Because of very wide variability, general recommendations for a safe number of fish servings may not be sufficient to protect the fetus. Analysis of hair mercury may be warranted before pregnancy in selected groups of women consuming more than 12 ounces of fish per week, as dietary modification can decrease body burden and ensure fetal safety.

In vitro testing for the diagnosis of anticonvulsant hypersensitivity syndrome: a systematic review.

Anticonvulsant hypersensitivity syndrome (AHS) is a rare and potentially fatal reaction that develops in susceptible patients following exposure to certain drugs, including aromatic anticonvulsants. Because of its ill-defined clinical picture and resemblance to other diseases, the diagnosis of AHS is often difficult and requires a safe and reliable diagnostic test. Other than systemic rechallenge, which is not always ethically permissible and has its own limitations, no reliable diagnostic test is available for this type of disorder. This systematic review attempts to evaluate the usefulness of the available in vitro tests in the diagnosis of AHS - namely, the lymphocyte transformation test (LTT) and the lymphocyte toxicity assay (LTA) - and to examine the different technical aspects of these tests that may contribute to their performance. We included studies in which aromatic anticonvulsant drugs were the likely causes of the hypersensitivity reaction and either the LTT or the LTA was used to aid the diagnosis of AHS. Analysis of original publications from 1950 to the last week of March 2009 and cited in PubMed, MEDLINE and EMBASE has revealed that there are numerous factors affecting the final result of the test, including the following: the timing of the test after exposure; the clinical manifestation of the reactions; the specific drug; and the test procedure and read-out system. In vitro diagnostic tests have the advantage over in vivo tests of being safe to use; however, in vitro tests for the diagnosis of AHS are not well standardized and their sensitivity and specificity are not yet determined. From the reviewed literature, the sensitivity of the LTT and the LTA seem to be around 70% and 90%, respectively, and the positive and negative predictive values of the tests in highly imputable cases are quite high. However, the lack of a gold-standard diagnostic test to prove drug culpability, along with the paucity of large-scale studies, precludes accurate determination of the epidemiological characteristics of these tests. It appears that without further understanding of the mechanisms underlying the pathophysiology of AHS, and how specific drugs and metabolites differentially affect these mechanisms, the development of more reliable tools for AHS diagnosis will be compromised. Consequently, in the absence of further research, the predictability of these tests will remain questionable and they are unlikely to be utilized on a large scale.

Defining a lowest observable adverse effect hair concentrations of mercury for neurodevelopmental effects of prenatal methylmercury exposure through maternal fish consumption: a systematic review.

BACKGROUND: Methylmercury is an environmental pollutant that can cause irreversible effects on the development of children. Although there is no doubt that high exposure can cause neurodevelopmental deficits, the threshold that will adversely affect the developing fetus is not well defined. Our objective was to systematically review the evidence of neurodevelopmental risks of methylmercury to the unborn child from maternal fish consumption to define the lowest observable adverse effect hair concentration (LOAEHC). METHODS: A systematic review was conducted of all original research reporting on the effects of methylmercury on the human fetus. A literature search was undertaken using SCOPUS, Medline-Ovid, PubMed, Google Scholar, and EMBASE. Papers were selected based on the following inclusion criteria: 1) child neurodevelopmental outcome; 2) comparison groups; and 3) methylmercury exposure through fish consumption. RESULTS: Forty-eight publications met these inclusion criteria. Thirty articles reported on longitudinal studies and 18 were cross-sectional studies. Variations in study design precluded formal meta-analysis. Based on an evaluation of these studies, we defined the LOAEHC at 0.3 microg/g of maternal hair mercury. The longitudinal studies yielded a LOAEHC of 0.5 microg/g. CONCLUSION: In the clinical context, the majority of pregnant women consume mercury-containing fish in amounts that are lower than the LOAEHC defined in this study. However, the LOAEHC is in the same order of magnitude of mercury exposure that occurs in significant numbers of women. Hence, although it appears safe to suggest that eating the recommended types and amounts of fish poses no measurable risks for neurodevelopmental deficits, analysis of hair mercury content before pregnancy might be suggested because dietary modification can decrease body content and risk.

Patch testing for the diagnosis of anticonvulsant hypersensitivity syndrome: a systematic review.

Anticonvulsant hypersensitivity syndrome (AHS), also known by the other names drug rash (reaction) with eosinophilia and systemic symptoms (DRESS) and drug-induced hypersensitivity syndrome (DIHS), is a rare and potentially fatal reaction that occurs in susceptible patients after exposure to certain drugs, including aromatic anticonvulsants. Because of its ill-defined clinical picture and resemblance to other diseases, the diagnosis of AHS is often difficult and requires a safe and reliable diagnostic test. The skin patch test has been proven to be very useful for prediction and diagnosis of some types of hypersensitivity reactions such as delayed drug eruptions to beta-lactam antibacterials. However, the diagnostic value of patch testing for AHS is yet to be determined and its negative predictive values (NPVs) and positive predictive values (PPVs) are still unknown. This systematic review attempts to evaluate the usefulness of patch tests in the diagnosis of AHS and to examine different technical aspects of patch testing that may contribute to its performance. We included studies in which aromatic anticonvulsant drugs are the likely causes of the hypersensitivity reaction. Analysis of original publications from 1950 to August 2008 and cited in PubMed, MEDLINE and EMBASE has revealed contradictory findings, possibly due mainly to the use of unstandardized methods. Numerous factors have been suggested to affect the final result of the test, including the following: type of drug tested; concentration of drug and vehicle used; timing of the test after exposure; and the clinical picture of the reaction. The PPV of the test in optimal conditions was as high as 80-90% depending on the drug tested. On the other hand, this value is around 10-20% in many other published studies. Although patch testing may be a useful diagnostic test for AHS, accurate determination of its sensitivity and specificity is yet to be achievable due to the lack of a gold standard test against which the performance of patch testing can be measured. Its PPV appears to be higher than its NPV, a matter that necessitates the use of other confirmatory tests in case of negative patch tests (e.g. careful systemic rechallenge). The benefit of testing appears to be maximal with certain drugs (i.e. carbamazepine and phenytoin) and for specific clinical manifestations (strong reactions). It should be performed 2-6 months after recovery from the date of the ADR for best results, with adequate vehicle control.

A surveillance method for the early identification of idiosyncratic adverse drug reactions.

BACKGROUND: Pemoline is a CNS stimulant that was introduced in 1975 in the US and was used to treat children with attention deficit hyperactivity disorder. Pemoline was withdrawn from the market 30 years later because of fatal hepatotoxicity associated with its use. OBJECTIVE: To create a system that will estimate the potential association between a serious adverse event and a medication early in its marketing cycle. METHOD: All case reports of acute liver failure associated with pemoline and reported to the US FDA from 1975 through 1999 were reviewed. All published articles on pemoline-induced hepatotoxicity were reviewed, and the Naranjo adverse drug reaction probability scale was applied. The incidence rate of idiopathic acute liver failure was estimated from the published literature. The data were analyzed using Fisher's Exact test and relative risks (RR) were calculated. RESULTS: As early as 1978, there was a significant signal indicating that pemoline was associated with acute liver failure, with an RR of 24.08 (95% CI 4.67, 124.10; p < 0.05). With an increased number of cases, the significance of the association had been steadily increased. CONCLUSION: This method enables researchers, clinicians, drug companies and regulators to identify uncommon adverse drug reactions, caused mostly by new medications, earlier than they currently are in the course of marketing and thus quantify serious adverse events.

Early steps in bilirubin-mediated apoptosis in murine hepatoma (Hepa 1c1c7) cells are characterized by aryl hydrocarbon receptor-independent oxidative stress and activation of the mitochondrial pathway.

Unconjugated bilirubin (UCB), the end product of heme catabolism, causes apoptosis in cells of the central nervous system, endothelial cells, and hepatotoma cells. However, the molecular mechanisms that contribute to UCB cytotoxicity remain unclear. The purpose of this study was to characterize the sequence of early events leading to UCB-mediated cytotoxicity in murine hepatoma Hepa 1c1c7 cells. In the present study, UCB (5-50 microM) was found to markedly increase the intracellular generation of reactive oxygen species (ROS) in a concentration-dependent manner, which is significantly elevated by 30 min post-treatment. This generation of ROS by UCB is not dependent on aryl hydrocarbon receptor (Ahr) signaling, as cells deficient in the Ahr (C12 cells) or the Ahr nuclear translocator protein (Arnt; C4 cells) were as efficient at generating ROS as wild type (WT) Hepa 1c1c7 cells. Mitochondrial membrane depolarization, evaluated with the lipophilic cationic dye, JC-1, occurred at least by 2 h after treatment with 50 muM UCB. Analysis of the caspase cascade demonstrated that activation of caspase-9 preceded activation of caspase-3. No conversion of procaspase-2 to active caspase-2 was detected in this study. These results demonstrate that UCB-mediated apoptosis in Hepa 1c1c7 cells is associated with increased oxidative stress and that caspase-9, and definitely not caspase-2, is the initiator caspase for apoptosis in UCB-treated Hepa 1c1c7 cells.

Excess nitric oxide decreases cytochrome P-450 2J4 content and P-450-dependent arachidonic acid metabolism in lungs of rats with acute pneumonia.

Recently, we demonstrated that pulmonary CYP2J4 content, a prominent source of EETs and HETEs formation in rat lungs, is reduced in pneumonia. Therefore, the purpose of this study was to determine the role of iNOS-derived NO in reduced pulmonary CYP2J4 protein content and decreased CYP metabolites in pneumonia. Rats were randomized to control, control plus 1400W (iNOS inhibitor), pneumonia, and pneumonia plus 1400W groups. Pseudomonas organisms were injected into lungs of pneumonia rats. At 40 h after surgery, rats were treated with either saline or 1400W for 4 h before death. Venous plasma samples were obtained for measuring nitrites/nitrates (NOx). There was no significant effect of 1400W on blood pressure measured in control or pneumonia rats, whereas 1400W reduced the elevated plasma NOx levels in pneumonia rats by half. CYP primary metabolites of AA formed at significantly lower rates in pulmonary microsomes from pneumonia rats compared with control rats. Treatment of pneumonia rats with 1400W resulted in a significant increase in the rate of formation of pulmonary EETs and omega-terminal HETEs compared with untreated pneumonia rats. The reduction in CYP2J4 protein content in pneumonia lung microsomes was also partially prevented by 1400W. Therefore, excess NO from iNOS decreases the pulmonary production of EETs and omega-HETEs in acute pneumonia. Inhibition of iNOS restores CYP2J4 protein content and CYP activity in acute pneumonia, indicating an important NO-CYP interaction in pulmonary responses to infection. We speculate CYP2J4 and its AA metabolites are involved in the modulation of pulmonary function in health and disease.

Biotransformation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in peripheral human lung microsomes.

The contributions of different enzymes to 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) biotransformation were assessed in human lung microsomes prepared from peripheral lung specimens obtained from seven subjects. Metabolite formation was expressed as a percentage of total recovered radioactivity from [5-3H]NNK and its metabolites per milligram of protein per minute. 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol was the major metabolite formed in the presence of an NADPH-generating system, with production ranging from 0.5186 to 1.268%/mg of protein/min, and total NNK bioactivation (represented by the sum of the four alpha-carbon hydroxylation endpoint metabolites) ranged from 0.002100 to 0.005685% alpha-hydroxylation/mg of protein/min. Overall, production of bioactivation metabolites was greater than that of detoxication (i.e., N-oxidation) products. Based on total bioactivation, subjects could be classified as high or low NNK bioactivators. In the presence of an NADPH-generating system, microsomal formation of the endpoint metabolite 1-(3-pyridyl)-1-butanone-4-carboxylic acid (keto acid) was consistently higher than that of all other alpha-carbon hydroxylation endpoint metabolites. Contributions of cytochrome p450 (p450) enzymes to NNK oxidation were demonstrated by NADPH dependence, inhibition by carbon monoxide, and inhibition by the nonselective p450 inhibitors proadifen hydrochloride (SKF-525A) and 1-aminobenzotriazole (ABT), particularly in lung microsomes from high bioactivators. At 5.0 mM, ABT inhibited total NNK bioactivation by 54 to 100%, demonstrating the importance of ABT-sensitive enzyme(s) in human pulmonary NNK bioactivation. Contributions of CYP2A6 and/or CYP2A13, as well as CYP2B6, to NNK bioactivation were also suggested by selective chemical and antibody inhibition in lung microsomes from some subjects. It is likely that multiple p450 enzymes contribute to human pulmonary microsomal NNK bioactivation, and that these contributions vary between individuals.

Pulmonary cytochrome P-450 2J4 is reduced in a rat model of acute Pseudomonas pneumonia.

We previously reported that the levels of epoxyeicosatrienoic acids (EETs) and 20-hydroxyeicosatetraenoic acid (20-HETE) are depressed in microsomes prepared from lungs of rats with acute Pseudomonas pneumonia. We also showed a potential role for cytochrome P-450 (CYP) metabolites of arachidonic acid (AA) in contractile responses of both normal pulmonary arteries and pulmonary arteries from rats with pneumonia. The CYP2J subfamily enzymes (endogenous source of EETs and HETEs) are constitutively expressed in human and rat lungs where they are localized in vascular smooth muscle and endothelium. The purpose of this study was to determine if CYP2J proteins are modified in pneumonia. Pseudomonas organisms were injected via a tracheostomy in the lungs of rats. Later (44 h), lungs were frozen, and microsomes were prepared from pneumonia and control rat lung homogenates. Lung microsomal proteins were then immunoblotted with anti-CYP2B1/2B2, anti-CYP4A, anti-CYP2J9pep2 (which reacts with rat CYP2J3), anti-CYP2J6pep1 (which reacts with rat CYP2J4), anti-CYP2J2pep4, or anti-CYP2J2pep3 (both of which react with all known CYP2J isozymes). Western blotting revealed a prominent 55-kDa band with anti-CYP2J2pep3, anti-CYP2J2pep4, and anti-CYP2J6pep1 (but not anti-CYP2J9pep2) that was reduced in pneumonia compared with control lung microsomes. The CYP2B bands (51-52 kDa) were less prominent and not different between pneumonia and control lungs. CYP4A proteins (20-HETE sources) were not detected in rat lung microsomes. Therefore, rat lung contains a protein with immunological characteristics similar to CYP2J4, and this CYP is reduced after pneumonia. We speculate that CYP2J (but not CYP2B) enzymes and their AA metabolic products (EETs) are involved in the modulation of pulmonary vascular tone in pneumonia in rats.