Gold(I) ion and the phosphine ligand are necessary for the anti-Toxoplasma gondii activity of auranofin.

Auranofin, an FDA-approved drug for rheumatoid arthritis, has emerged as a promising antiparasitic medication in recent years. The gold(I) ion in auranofin is postulated to be responsible for its antiparasitic activity. Notably, aurothiomalate and aurothioglucose also contain gold(I), and, like auranofin, they were previously used to treat rheumatoid arthritis. Whether they have antiparasitic activity remains to be elucidated. Herein, we demonstrated that auranofin and similar derivatives, but not aurothiomalate and aurothioglucose, inhibited the growth of Toxoplasma gondii in vitro. We found that auranofin affected the T. gondii biological cycle (lytic cycle) by inhibiting T. gondii's invasion and triggering its egress from the host cell. However, auranofin could not prevent parasite replication once T. gondii resided within the host. Auranofin treatment induced apoptosis in T. gondii parasites, as demonstrated by its reduced size and elevated phosphatidylserine externalization (PS). Notably, the gold from auranofin enters the cytoplasm of T. gondii, as demonstrated by scanning transmission electron microscopy-energy dispersive X-ray spectroscopy (STEM-EDS) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS).IMPORTANCEToxoplasmosis, caused by Toxoplasma gondii, is a devastating disease affecting the brain and the eyes, frequently affecting immunocompromised individuals. Approximately 60 million people in the United States are already infected with T. gondii, representing a population at-risk of developing toxoplasmosis. Recent advances in treating cancer, autoimmune diseases, and organ transplants have contributed to this at-risk population's exponential growth. Paradoxically, treatments for toxoplasmosis have remained the same for more than 60 years, relying on medications well-known for their bone marrow toxicity and allergic reactions. Discovering new therapies is a priority, and repurposing FDA-approved drugs is an alternative approach to speed up drug discovery. Herein, we report the effect of auranofin, an FDA-approved drug, on the biological cycle of T. gondii and how both the phosphine ligand and the gold molecule determine the anti-parasitic activity of auranofin and other gold compounds. Our studies would contribute to the pipeline of candidate anti-T. gondii agents.

Chemical and Cellular Formation of Reactive Oxygen Species from Secondary Organic Aerosols in Epithelial Lining Fluid.

INTRODUCTION: Oxidative stress mediated by reactive oxygen species (ROS) is a key process for adverse aerosol health effects. Secondary organic aerosols (SOA) account for a major fraction of particulate matter with aerodynamic diameter ≤2.5 µm (PM2.5). PM2.5 inhalation and deposition into the respiratory tract causes the formation of ROS by chemical reactions and phagocytosis of macrophages in the epithelial lining fluid (ELF), but their relative contributions are not well quantified and their link to oxidative stress remains uncertain. The specific aims of this project were (1) elucidating the chemical mechanism and quantifying the formation kinetics of ROS in the ELF by SOA; (2) quantifying the relative importance of ROS formation by chemical reactions and macrophages in the ELF. METHODS: SOA particles were generated using reaction chambers from oxidation of various precursors including isoprene, terpenes, and aromatic compounds with or without nitrogen oxides (NOx). We collected size-segregated PM at two highway sites in Anaheim, CA, and Long Beach, CA, and at an urban site in Irvine, CA, during two wildfire events. The collected particles were extracted into water or surrogate ELF that contained lung antioxidants. ROS generation was quantified using electron paramagnetic resonance (EPR) spectroscopy with a spin-trapping technique. PM oxidative potential (OP) was also quantified using the dithiothreitol assay. In addition, kinetic modeling was applied for analysis and interpretation of experimental data. Finally, we quantified cellular superoxide release by RAW264.7 macrophage cells upon exposure to quinones and isoprene SOA using a chemiluminescence assay as calibrated with an EPR spin-probing technique. We also applied cellular imaging techniques to study the cellular mechanism of superoxide release and oxidative damage on cell membranes. RESULTS: Superoxide radicals (·O2-) were formed from aqueous reactions of biogenic SOA generated by hydroxy radical (·OH) photooxidation of isoprene, ß-pinene, α-terpineol, and d-limonene. The temporal evolution of ·OH and ·O2- formation was elucidated by kinetic modeling with a cascade of aqueous reactions, including the decomposition of organic hydroperoxides (ROOH), ·OH oxidation of primary or secondary alcohols, and unimolecular decomposition of α-hydroxyperoxyl radicals. Relative yields of various types of ROS reflected the relative abundance of ROOH and alcohols contained in SOA, which generated under high NOx conditions, exhibited lower ROS yields. ROS formation by SOA was also affected by pH. Isoprene SOA had higher ·OH and organic radical yields at neutral than at acidic pH. At low pH ·O2- was the dominant species generated by all types of SOA. At neutral pH, α-terpineol SOA exhibited a substantial yield of carbon-centered organic radicals (R·), while no radical formation was observed by aromatic SOA.Organic radicals in the ELF were formed by mixtures of Fe2+ and SOA generated from photooxidation of isoprene, α-terpineol, and toluene. The molar yields of organic radicals by SOA were 5-10 times higher in ELF than in water. Fe2+ enhanced organic radical yields by a factor of 20-80. Ascorbate mediated redox cycling of iron ions and sustained organic peroxide decomposition, as supported by kinetic modeling reproducing time- and concentration-dependence of organic radical formation, as well as by additional experiments observing the formation of Fe2+ and ascorbate radicals in mixtures of ascorbate and Fe3+. ·OH and superoxide were found to be efficiently scavenged by antioxidants.Wildfire PM mainly generated ·OH and R· with minor contributions from superoxide and oxygen-centered organic radicals (RO·). PM OP was high in wildfire PM, exhibiting very weak correlation with radical forms of ROS. These results were in stark contrast with PM collected at highway and urban sites, which generated much higher amounts of radicals dominated by ·OH radicals that correlated well with OP. By combining field measurements of size-segregated chemical composition, a human respiratory tract model, and kinetic modeling, we quantified production rates and concentrations of different types of ROS in different regions of the ELF by considering particle-size-dependent respiratory deposition. While hydrogen peroxide (H2O2) and ·O2- production were governed by Fe and Cu ions, ·OH radicals were mainly generated by organic compounds and Fenton-like reactions of metal ions. We obtained mixed results for correlations between PM OP and ROS formation, providing rationale and limitations of the use of oxidative potential as an indicator for PM toxicity in epidemiological and toxicological studies.Quinones and isoprene SOA activated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in macrophages, releasing massive amounts of superoxide via respiratory burst and overwhelming the superoxide formation by aqueous chemical reactions in the ELF. The threshold dose for macrophage activation was much smaller for quinones compared with isoprene SOA. The released ROS caused lipid peroxidation to increase cell membrane fluidity, inducing oxidative damage and stress. Further increases of doses led to the activation of antioxidant response elements, reducing the net cellular superoxide production. At very high doses and long exposure times, chemical production became comparably important or dominant if the escalation of oxidative stress led to cell death. CONCLUSIONS: The mechanistic understandings and quantitative information on ROS generation by SOA particles provided a basis for further elucidation of adverse aerosol health effects and oxidative stress by PM2.5. For a comprehensive assessment of PM toxicity and health effects via oxidative stress, it is important to consider both chemical reactions and cellular processes for the formation of ROS in the ELF. Chemical composition of PM strongly influences ROS formation; further investigations are required to study ROS formation from various PM sources. Such research will provide critical information to environmental agencies and policymakers for the development of air quality policy and regulation.

The impact of alcohol use on tuberculosis treatment outcomes: a systematic review and meta-analysis.

Alcohol use is associated with increased risk of developing tuberculosis (TB) disease, yet the impact of alcohol use on TB treatment outcomes has not been summarized. We aimed to quantitatively review evidence of the relationship between alcohol use and poor TB treatment outcomes. We conducted a systematic review of PubMed, EMBASE, and Web of Science (January 1980-May 2018). We categorized studies as having a high- or low-quality alcohol use definition and examined poor treatment outcomes individually and as two aggregated definitions (i.e., including or excluding loss to follow-up [LTFU]). We analyzed drug-susceptible (DS-) and multidrug-resistant (MDR-) TB studies separately. Our systematic review yielded 111 studies reporting alcohol use as a predictor of DS- and MDR-TB treatment outcomes. Alcohol use was associated with increased odds of poor treatment outcomes (i.e., death, treatment failure, and LTFU) in DS (OR 1.99, 95% CI 1.57-2.51) and MDR-TB studies (OR 2.00, 95% CI 1.73-2.32). This association persisted for aggregated poor treatment outcomes excluding LTFU, each individual poor outcome, and across sub-group and sensitivity analyses. Only 19% of studies used high-quality alcohol definitions. Alcohol use significantly increased the risk of poor treatment outcomes in both DS- and MDR-TB patients. This study highlights the need for improved assessment of alcohol use in TB outcomes research and potentially modified treatment guidelines for TB patients who consume alcohol.

Proteomic changes driven by urban pollution suggest particulate matter as a deregulator of energy metabolism, mitochondrial activity, and oxidative pathways in the rat brain.

The adverse effects of air pollution have been long studied in the lung and respiratory systems, but the molecular changes that this causes at the central nervous system level have yet to be fully investigated and understood. To explore the evolution with time of protein expression levels in the brain of rats exposed to particulate matter of different sizes, we carried out two-dimensional gel electrophoresis followed by determination of dysregulated proteins through Coomassie blue staining-based densities (SameSpots software) and subsequent protein identification using MALDI-based mass spectrometry. Expression differences in dysregulated proteins were found to be statistically significant with p-value <0.05. A systems biology-based approach was utilized to determine critical biochemical pathways involved in the rats' brain response. Our results suggest that rats' brains have a particulate matter size dependent-response, being the mitochondrial activity and the astrocyte function severely affected. Our proteomic study confirms the dysregulation of different biochemical pathways involving energy metabolism, mitochondrial activity, and oxidative pathways as some of the main effects of PM exposure on the rat brain. SIGNIFICANCE: Rat brains exposed to particulate matter with origin in car engines are affected in two main areas: mitochondrial activity, by the dysregulation of many pathways linked to the respiratory chain, and neuronal and astrocytic function, which stimulates brain changes triggering tumorigenesis and neurodegeneration.

Extraskeletal Calcifications in Hutchinson-Gilford Progeria Syndrome.

PURPOSE: Children with Hutchinson-Gilford progeria syndrome (HGPS), a rare premature aging disease, exhibit extraskeletal calcifications detected by radiographic analysis and on physical examination. The aim of this study was to describe the natural history and pathophysiology of these abnormal calcifications in HGPS, and to determine whether medications and/or supplements tested in clinical trials alter their development. METHODS: Children from two successive clinical trials administering 1) lonafarnib (n = 26) and 2) lonafarnib + pravastatin + zoledronic acid (n = 37) were studied at baseline (pre-therapy), one year on therapy, and at end-of-therapy (3.3-4.3 years after the baseline visit). Calcium supplementation (oral calcium carbonate) was administered during the first year of the second trial and was subsequently discontinued. Information on calcifications was obtained from physical examinations, radiographs, and serum and urinary biochemical measures. The mineral content of two skin-derived calcifications was determined by x-ray diffraction. RESULTS: Extraskeletal calcifications were detected radiographically in 12/39 (31%) patients at baseline. The odds of exhibiting calcifications increased with age (p = 0.045). The odds were unaffected by receipt of lonafarnib, pravastatin, and zoledronate therapies. However, administration of calcium carbonate supplementation, in conjunction with all three therapeutic agents, significantly increased the odds of developing calcifications (p = 0.009), with the odds plateauing after the supplement's discontinuation. Composition analysis of calcinosis cutis showed hydroxyapatite similar to bone. Although serum calcium, phosphorus, and parathyroid hormone (PTH) were within normal limits at baseline and on-therapy, PTH increased significantly after lonafarnib initiation (p < 0.001). Both the urinary calcium/creatinine ratio and tubular reabsorption of phosphate (TRP) were elevated at baseline in 22/39 (56%) and 31/37 (84%) evaluable patients, respectively, with no significant changes while on-therapy. The mean calcium × phosphorus product (Ca × Pi) was within normal limits, but plasma magnesium decreased over both clinical trials. Fibroblast growth factor 23 (FGF23) was lower compared to age-matched controls (p = 0.03). CONCLUSIONS: Extraskeletal calcifications increased with age in children with HGPS and were composed of hydroxyapatite. The urinary calcium/creatinine ratio and TRP were elevated for age while FGF23 was decreased. Magnesium decreased and PTH increased after lonafarnib therapy which may alter the ability to mobilize calcium. These findings demonstrate that children with HGPS with normal renal function and an unremarkable Ca × Pi develop extraskeletal calcifications by an unidentified mechanism that may involve decreased plasma magnesium and FGF23. Calcium carbonate accelerated their development and is, therefore, not recommended for routine supplementation in these children.

Phosphorylation of a constrained azacyclic FTY720 analog enhances anti-leukemic activity without inducing S1P receptor activation.

The frequency of poor outcomes in relapsed leukemia patients underscores the need for novel therapeutic approaches. The Food and Drug Administration-approved immunosuppressant FTY720 limits leukemia progression by activating protein phosphatase 2A and restricting nutrient access. Unfortunately, FTY720 cannot be re-purposed for use in cancer patients due to on-target toxicity associated with S1P receptor activation at the elevated, anti-neoplastic dose. Here we show that the constrained azacyclic FTY720 analog SH-RF-177 lacks S1P receptor activity but maintains anti-leukemic activity in vitro and in vivo. SH-RF-177 was not only more potent than FTY720, but killed via a distinct mechanism. Phosphorylation is dispensable for FTY720's anti-leukemic actions. However, chemical biology and genetic approaches demonstrated that the sphingosine kinase 2 (SPHK2)-mediated phosphorylation of SH-RF-177 led to engagement of a pro-apoptotic target and increased potency. The cytotoxicity of membrane-permeant FTY720 phosphonate esters suggests that the enhanced potency of SH-RF-177 stems from its more efficient phosphorylation. The tight inverse correlation between SH-RF-177 IC50 and SPHK2 mRNA expression suggests a useful biomarker for SH-RF-177 sensitivity. In summary, these studies indicate that FTY720 analogs that are efficiently phosphorylated but fail to activate S1P receptors may be superior anti-leukemic agents compared to compounds that avoid cardiotoxicity by eliminating phosphorylation.

Nitrogen dioxide and ozone as factors in the availability of lead from lead-based paints.

Lead-based paint remains a pervasive problem in U.S. cities, and an increasing problem in the developing world where it is still manufactured and used. Little attention has focused on the factors that increase the release of lead pigment granules from painted surfaces. Nitrogen dioxide (NO(2)) and ozone (O(3)) from transportation emissions in urban environments have the potential to react with and remove polymeric binders in paint, making pigment granules more available for subsequent transfer to hands on contact, or deposition in housedust. Here we show that exposure to NO(2) and O(3) increased the lead in wipe samples of stainless steel surfaces painted with alkyd low gloss solvent lead-based paint by 296% +/- 101 (or 0.24 microg/cm(2)) and 37% +/- 21 (or 0.025 microg/cm(2)), respectively, with corresponding changes in surface morphology indicated by reflectometry and scanning electron microscopy. Lead release from unexposed low gloss acrylic household paints was 40 times greater than comparable solvent based paints. Given that lead-based paint is still manufactured and used in many urban areas of the developing world where O(3) concentrations currently exceed historic U.S. concentrations, the interaction of air pollution with lead painted indoor surfaces may pose greater exposure risks for lead poisoning in children than previously anticipated.

Inhaled ultrafine particulate matter affects CNS inflammatory processes and may act via MAP kinase signaling pathways.

In addition to evidence that inhalation of ambient particulate matter (PM) can increase cardiopulmonary morbidity and mortality, the brain may also constitute a site adversely effected by the environmental presence of airborne particulate matter. We have examined the association between exposure to PM and adverse CNS effects in apolipoprotein E knockout (ApoE-/-) mice exposed to two levels of concentrated ultrafine particulate matter in central Los Angeles. Mice were euthanized 24h after the last exposure and brain, liver, heart, lung and spleen tissues were collected and frozen for subsequent bioassays. There was clear evidence of aberrant immune activation in the brains of exposed animals as judged by a dose-related increase in nuclear translocation of two key transcription factors, NF-kappaB and AP-1. These factors are involved in the promotion of inflammation. Increased levels of glial fibrillary acidic protein (GFAP) were also found consequent to particulate inhalation suggesting that glial activation was taking place. In order to determine the mechanism by which these events occurred, levels of several MAP kinases involved in activation of these transcription factors were assayed by Western blotting. There were no significant changes in the proportion of active (phosphorylated) forms of ERK-1, IkB and p38. However, the fraction of JNK in the active form was significantly increased in animals receiving the lower concentration of concentrated ambient particles (CAPs). This suggests that the signaling pathway by which these transcription factors are activated involves the activation of JNK.

Effect of cigarette smoking on nitric oxide, structural, and mechanical properties of mouse arteries.

Cigarette smoking (CS) is a major risk factor for vascular disease. The aim of this study was to quantitatively assess the influence of CS on mouse arteries. We studied the effect of short-term (6 wk) and long-term (16 wk) CS exposure on structural and mechanical properties of coronary arteries compared with that of control mice. We also examined the reversibility of the deleterious effects of CS on structural [e.g., wall thickness (WT)], mechanical (e.g., stiffness), and biochemical [e.g., nitric oxide (NO) by-products] properties with the cessation of CS. The left and right coronary arteries were cannulated in situ and mechanically distended. The stress, strain, elastic modulus, and WT of coronary arteries were determined. Western blot analysis was used to analyze endothelial NO synthase (eNOS) in the femoral and carotid arteries of the same mice, and NO by-products were determined by measuring the levels of nitrite. Our results show that the mean arterial pressure was increased by CS. Furthermore, CS significantly increased the elastic modulus, decreased stress and strain, and increased the WT and WT-to-radius ratio compared with those of control mice. The reduction of eNOS protein expression was found only after long-term CS exposure. Moreover, the NO metabolite was markedly decreased in CS mice after short- and long-term exposure of CS. These findings suggest that 16 wk of CS exposure can cause an irreversible deterioration of structural and elastic properties of mouse coronary arteries. The decrease in endothelium-derived NO in CS mice was seen to significantly correlate with the remodeling of arterial wall.

Pb enamel biomarker: deposition of pre- and postnatal Pb isotope injection in reconstructed time points along rat enamel transect.

Exposure to lead (Pb) as well as other heavy metals in the environment is still a matter of public health concern. The development of the enamel biomarker for heavy metal exposure assessment is designed to improve studies of dose-effect relationships to developmental anomalies, particularly embryonic dysfunctions, and to provide a time-specific recount of past exposures. The work presented in this paper demonstrates maternal transfer across the placental barrier of the enriched isotope (206)Pb tracer to the enamel of the rat pup. Likewise, injections of (204)Pb-enriched tracer in the neonate rat resulted in deposition of the tracer in the enamel histology as measured by secondary ion microprobe spectrometry. Through enamel, we were able to observe biological removal and assimilation of prenatal and postnatal tracers, respectively. This research demonstrates that enamel can be used as a biomarker of exposure to Pb and may illustrate the toxicokinetics of incorporating Pb into fetal and neonatal steady-state system processes. The biomarker technique, when completely developed, may be applied to cross-sectional and longitudinal epidemiological research.

Particulate matter in polluted air may increase biomarkers of inflammation in mouse brain.

The etiology of neurodegenerative disorders is at present unknown. However, many of these disorders are associated with an increase in oxidative and inflammatory events. Although a small percentage of these disorders are familial cases linked to specific genetic defects, most are idiopathic. Thus, environmental factors are thought to play an important role in the onset and progression of such disorders. We have demonstrated that exposure (4 h, 5 days per week for 2 weeks) to concentrated airborne particulate matter increases inflammatory indices in brain of ovalbumin-sensitized BALB/c mice. Animals were divided into three exposure groups: filtered air (control), ultrafine particles, or fine and ultrafine particles. The levels of proinflammatory cytokines interleukin-1 alpha (IL-1alpha) and tumor necrosis factor alpha (TNF-alpha) were increased in brain tissue of mice exposed to particulate matter compared to that of control animals. Levels of the immune-related transcription factor NF-kappaB were also found to be substantially elevated in the brain of exposed groups compared with the control group. These data indicate that components of inhaled particulate matter may trigger a proinflammatory response in nervous tissue that could contribute to the pathophysiology of neurodegenerative diseases.

Ambient fine and coarse particle suppression of alveolar macrophage functions.

Alveolar macrophages (AM) are part of the innate immunological defense system and are among the first cells to respond to the effects of inhaled particles. Study of macrophage responses to particles is, therefore, relevant to understanding the mechanisms by which inhaled particles can adversely affect health. Size-fractionated ambient particles were collected at traffic-dominated sites in The Netherlands using a mobile high volume slit impactor system. AM were obtained by bronchoalveolar lavage from adult as well as aged rats and were incubated with for 4 h with collected particles at concentrations of 25-1000 pg per cell. Free radical generation by AM was measured with and without stimulation of AM with phorbol myristate acetate (PMA). There were dose-dependent decreases in macrophage production of superoxide radicals as measured by the chemiluminescent method. Coarse particles were more toxic than were fine particles. Suppression of free radical production did not seem to be related to the presence of bioavailable iron or to endotoxin associated with the particles. There were no statistically significant differences related to age or strain of the rats tested. We conclude that in vitro tests using AM is a useful and rapid method for delineating differences in toxicity between environmental samples of size fractionated ambient particles.

Anti-inhibitor coagulant complex for the rescue therapy of acquired inhibitors to factor VIII: case report and review of the literature.

A 62-year-old African-American man with a history of hypertension, asthma, and prostate cancer, but no prior history of haemophilia presented with gross haematuria following a motor vehicle accident. Coagulation studies revealed a prolonged partial thromboplastin time. Subsequent mixing study and factor analysis confirmed factor VIII (FVIII) deficiency. The patient subsequently developed a knee haemarthrosis associated with persistent haematuria and a profoundly elevated FVIII inhibitor titre. Fresh frozen plasma was initiated upon presentation. Once FVIII inhibitor was discovered, immunosuppressive agents were started. Concurrent treatment with acute bypass agents including porcine FVIII, and recombinant human factor VIIa (rFVIIa;NovoSeven), was also given. Ultimately, anti-inhibitor coagulant complex (Autoplex T) was administered, stabilizing the haematuria and haemarthrosis. There was no additional bleeding 6 months after the last dose of anti-inhibitor coagulant complex. This case is consistent with others in which anti-inhibitor coagulant complex therapy was used successfully to manage patients with serious acute bleeding problems who are found to have acquired inhibitors to factor VIII.

Measurements of manganese with respect to calcium in histological enamel cross sections: toward a new manganese biomarker.

Airborne Mn may become an important route of exposure if the use of Mn-containing gasoline additives becomes more widespread. We report on the measurement of manganese and calcium in histological cross sections of shed deciduous tooth enamel of three human subjects. The goal of this research was to measure Mn in tooth enamel for use as a biomarker in assessing manganese exposure in cross-sectional and longitudinal studies. The histological locations can be time-specific (analogous to examining growth rings in trees). This technique, which may identify critical windows of exposure, can be important for evaluating potential vulnerability of the fetus and neonate to inhaled or ingested Mn.

Respiratory tract responses to repeated inhalation of an oxidant and acid gas-particle air pollutant mixture.

The purpose of this study was to examine a broad range of toxicologic responses in rats exposed to a multi-component pollutant atmosphere. Cumulative and adaptive respiratory tract responses to 3 concentrations of an inhaled particle-oxidant mixture were examined in Fisher 344 N rats exposed 4 h/day, 3 days/week for 4 weeks. The mixtures contained O3, NO2, NH4HSO4, carbon particles, and HNO3 vapor. Irritant-induced, rapid-shallow breathing responses were present during the first 4-h exposure to medium and high concentrations. Successive exposures showed diminished responses in medium concentrations and exacerbated responses in high concentrations. At the end of 4 weeks, rats exposed to high concentrations exhibited lung lesions. Lavaged pulmonary macrophages showed dose-dependent depressions of Fc-receptor binding and phagocytosis. Lung tissue macrophages showed dose-dependent increases in acid phosphatase staining density and carbon particles. Respiratory tract clearance of tracer particles was not significantly affected by the exposures. Broncho-alveolar epithelial permeability was increased by the high concentration. Epithelial cell-proliferation labeling showed a dose-dependent increase at all levels of the respiratory tract. Progressively exacerbated breathing-pattern responses at high concentrations were associated with lung lesions and high cell-proliferation labeling in the nose transitional epithelium and terminal bronchioles. Attenuating or adaptive breathing-pattern responses occurred in the presence of smaller, but in many cases still significant, compromise of respiratory functions. Either attenuating or exacerbated breathing-pattern responses can occur in the presence of a significant dose-dependent compromise of other respiratory functions and lung tissue injury.

Neuromelanin biosynthesis is driven by excess cytosolic catecholamines not accumulated by synaptic vesicles.

Melanin, the pigment in hair, skin, eyes, and feathers, protects external tissue from damage by UV light. In contrast, neuromelanin (NM) is found in deep brain regions, specifically in loci that degenerate in Parkinson's disease. Although this distribution suggests a role for NM in Parkinson's disease neurodegeneration, the biosynthesis and function of NM have eluded characterization because of lack of an experimental system. We induced NM in rat substantia nigra and PC12 cell cultures by exposure to l-dihydroxyphenylalanine, which is rapidly converted to dopamine (DA) in the cytosol. This pigment was identical to human NM as assessed by paramagnetic resonance and was localized in double membrane autophagic vacuoles identical to NM granules of human substantia nigra. NM synthesis was abolished by adenoviral-mediated overexpression of the synaptic vesicle catecholamine transporter VMAT2, which decreases cytosolic DA by increasing vesicular accumulation of neurotransmitter. The NM is in a stable complex with ferric iron, and NM synthesis was inhibited by the iron chelator desferrioxamine, indicating that cytosolic DA and dihydroxyphenylalanine are oxidized by iron-mediated catalysis to membrane-impermeant quinones and semiquinones. NM synthesis thus results from excess cytosolic catecholamines not accumulated into synaptic vesicles. The permanent accumulation of excess catechols, quinones, and catechol adducts into a membrane-impermeant substance trapped in organelles may provide an antioxidant mechanism for catecholamine neurons. However, NM in organelles associated with secretory pathways may interfere with signaling, as it delays stimulated neurite outgrowth in PC12 cells.

Evaluation of a real-time passive personal particle monitor in fixed site residential indoor and ambient measurements.

Recent experimental findings in animals and humans indicate adverse respiratory effects from short-term exposures to particulate air pollutants, especially in sensitive subpopulations such as asthmatics. The relationship between air pollution and asthma has mainly been determined using particulate matter (PM) measurements from central sites. Validated tools are needed to assess exposures most relevant to health effects. Recently, a personal passive particulate sampler (personal Data-RAM, pDR, MIE Inc., Bedford, MA) has become available for studying personal exposures to PM with time resolution at 1 min. The pDR measures light scatter from PM in the 0.1-10 microM range, the significant range for health effects. In order to assess the ability of the pDR in predicting gravimetric mass, pDRs were collocated with PM2.5 and PM10 Harvard Impactors (HI) inside and outside nine homes of asthmatic children and at an outdoor central Air Pollution Control District site. Results are presented of comparisons between the HI samplers and the pDR in various modes of operation: passive, active, and active with a heated inlet. When used outdoors at fixed sites the pDR readings exhibit interference from high relative humidity (RH) unless operated with a method for drying inlet air such as a heater, or if readings at times of high RH are adjusted. The pDR correlates more highly with the HI PM2.5 than with the HI PM10 (r2 = 0.66 vs. 0.13 for outdoors, r2 = 0.42 vs. 0.20 for indoors). The pDR appears to be a useful tool for an epidemiologic study that aims to examine the relationship between health outcomes and personal exposure to peaks in PM.

Effect of serial-day exposure to nitrogen dioxide on airway and blood leukocytes and lymphocyte subsets.

Nitrogen dioxide (NO2) is a free radical-producing oxidant gas. Inhalation of NO2 could cause airway inflammation, and decrease immune function. This experiment tested the hypothesis that exposure to NO2 would: 1) increase leukocytes in bronchoalveolar lavage (BAL); and 2) change the distribution of lymphocyte subsets and activation in BAL and peripheral blood (PB). Using a counter-balanced, repeated-measures design, 15 healthy volunteers were exposed to filtered air (FA) or 2.0 parts per million NO2 for 4 h x day(-1) (4 x 30 min of exercise), for three consecutive days. Bronchoscopy was performed 18 h following each exposure set, and PB was drawn pre-exposure and pre-bronchoscopy. Flow cytometry was used to enumerate lymphocyte subsets and activation makers in BAL and PB. In the bronchial fraction, there was an increase in the percentage of neutrophils following NO2 exposure compared to FA (median (interquartile range): 10.6 (4.8-17.2)% versus 5.3 (2.5-8.3)%; p=0.005). In the BAL, there was a decrease in the percentage of T-helper cells following NO2 exposure compared to FA (55.9 (40.8-62.7)% versus 61.6 (52.6-65.2)%; p=0.022). For PB, there were no between-condition differences in any leukocyte or lymphocyte subsets, or activation. In conclusion exposure to nitrogen dioxide results in bronchial inflammation and a minimal change in bronchoalveolar lavage T-helper cells, and no changes in peripheral blood cells.

Modern psychometric methods for detection of differential item functioning: application to cognitive assessment measures.

Cognitive screening tests and items have been found to perform differently across groups that differ in terms of education, ethnicity and race. Despite the profound implications that such bias holds for studies in the epidemiology of dementia, little research has been conducted in this area. Using the methods of modern psychometric theory (in addition to those of classical test theory), we examined the performance of the Attention subscale of the Mattis Dementia Rating Scale. Several item response theory models, including the two- and three-parameter dichotomous response logistic model, as well as a polytomous response model were compared. (Log-likelihood ratio tests showed that the three-parameter model was not an improvement over the two-parameter model.) Data were collected as part of the ten-study National Institute on Aging Collaborative investigation of special dementia care in institutional settings. The subscale KR-20 estimate for this sample was 0.92. IRT model-based reliability estimates, provided at several points along the latent attribute, ranged from 0.65 to 0.97; the measure was least precise at the less disabled tail of the distribution. Most items performed in similar fashion across education groups; the item characteristic curves were almost identical, indicating little or no differential item functioning (DIF). However, four items were problematic. One item (digit span backwards) demonstrated a large error term in the confirmatory factor analysis; item-fit chi-square statistics developed using BIMAIN confirm this result for the IRT models. Further, the discrimination parameter for that item was low for all education subgroups. Generally, persons with the highest education had a greater probability of passing the item for most levels of theta. Model-based tests of DIF using MULTILOG identified three other items with significant, albeit small, DIF. One item, for example, showed non-uniform DIF in that at the impaired tail of the latent distribution, persons with higher education had a higher probability of correctly responding to the item than did lower education groups, but at less impaired levels, they had a lower probability of a correct response than did lower education groups. Another method of detection identified this item as having DIF (unsigned area statistic=3.05, p<0.01, and 2.96, p<0.01). On average, across the entire score range, the lower education group's probability of answering the item correctly was 0.11 higher than the higher education group's probability. A cross-validation with larger subgroups confirmed the overall result of little DIF for this measure. The methods used for detecting differential item functioning (which may, in turn, be indicative of bias) were applied to a neuropsychological subtest. These methods have been used previously to examine bias in screening measures across education and ethnic and racial subgroups. In addition to the important epidemiological applications of ensuring that screening measures and neuropsychological tests used in diagnoses are free of bias so that more culture-fair classifications will result, these methods are also useful for the examination of site differences in large multi-site clinical trials. It is recommended that these methods receive wider attention in the medical statistical literature.

Unsuspected splenic rupture in a neonate.

Serious intra-abdominal injuries in neonates are very rare. In addition, the signs and symptoms of hemoperitoneum caused by bleeding from solid viscera are vague and nonspecific and often are not recognized before the onset of hypovolemic shock or death. In this report, we describe a 2-day-old infant who presented with shock and pallor who had a ruptured spleen, presumably from birth. We also review the literature and the importance of recognizing this injury in the emergency department setting.