Rapid switching from levetiracetam to brivaracetam in pharmaco-resistant epilepsy in people with and without intellectual disabilities: a naturalistic case control study

BACKGROUND

Approximately one quarter of people with an intellectual disability (PwID) have epilepsy of whom nearly three-quarters are pharmaco-resistant. There are higher reported neuropsychiatric side-effects to anti-seizure medication (ASM) in this group. Levetiracetam (LEV) is a first-line ASM with a stronger association with neuropsychiatric symptoms for PwID than other ASMs. Brivaracetam (BRV) is a newer ASM. Recent studies suggest a beneficial effect of swapping people who experience neuropsychiatric events with LEV to BRV. However, there is limited evidence of this for PwID. This evaluation analyses real world outcomes of LEV to BRV swap for PwID compared to those without ID.

METHODS

We performed a multicentre, retrospective review of clinical records. Demographic, clinical characteristics and reported adverse events of patients switched from LEV to BRV (2016-2020) were recorded at 3 months pre and 6- and 12-month post-BRV initiation. Outcomes were compared between PwID and those without and summarised using cross-tabulations and logistic regression models. A Bonferroni correction was applied.

RESULTS

Of 77 participants, 46 had ID and 52% had a past psychiatric illness. 71% participants switched overnight from LEV to BRV. Seizure reduction of > 50% was seen in 40% patients. Psychiatric illness history was predictive of having neuropsychiatric side-effects with LEV but not BRV (p = 0.001). There was no significant difference for any primary outcomes between PwID versus without ID.

CONCLUSIONS

Switching from LEV to BRV appears as well tolerated and efficacious in PwID as those without ID with over 90% still on BRV after 12 months.

GlioPredictor: A Deep Learning Model for Identification of High-Risk Low-Grade Glioma toward Adjuvant Treatment Planning

PURPOSE/OBJECTIVE(S)

High-risk low-grade glioma (LGG) patients are recommended to undergo adjuvant radiotherapy whereas watchful waiting is recommended for low-risk LGG patients per the latest NCCN guidelines. Based on Radiation Therapy Oncology Group (RTOG) 9802, high-risk features include age >40 or subtotal resection (STR). However, in the era of molecular-based classification for tumors of central neural system, current risk classification criteria based on gross disease and patient demographics may be outdated. Here, we aim to develop a molecular-based glioma risk classification system (GlioPredictor) that could potentially facilitate identification of high-risk LGG patients.

MATERIALS/METHODS

A total of 507 LGG cases from The Cancer Genome Atlas-low grade glioma (TCGA-LGG), and 1,309 cases from AACR GENIE v13.0 datasets were studied for genetic disparities between IDH1-wildtype and mutated cohorts, and varying age groups. Through a feature selection technique using genomic profiling and correlation analyses, features such as mutation status, copy number variations (CNVs), among other clinicopathologic features prognostic of IDH1 mutation status were selected as potential inputs to train an artificial neural networks (ANNs) that could predict IDH1 mutation status. Model performance was assessed using the area under the receiver operating characteristic curve (AUC). Memorial Sloan Kettering (MSK) dataset (n = 404) for LGG was used to cross-validate the trained ANN. The optimized ANN model has 6 layers with 6 input nodes, 20 hidden nodes, and a binary output layer. The weights and biases of the hidden layers of the best-performing model were retrieved and reconstructed to yield the GlioPredictor score-the predicted risk of progression for IDH1-wildtype LGG.

RESULTS

Over 81% of glioma patients age less than 40 have IDH1 mutation, as compared with 31% in those age above 60. Using age > 40 as a cutoff failed to identify high-risk IDH1-mutant LGG with early progression. IDH1 mutation is associated with decreased CNVs of EGFR (21 % vs. 3%), CDKN2A (20% vs. 6%) and PTEN (14% vs. 1.7%), and increased percentage of mutations for TP53 (15% vs. 63%), and ATRX (10% vs. 54%) (p<0.001). Using these molecular features, along with the patient's age, an ANN model with 6 layers and 20 hidden nodes can predict IDH1 mutation status with over 90% accuracy and AUC score over 0.91.

CONCLUSION

We have developed an ANN model that is capable of learning the prognostic features of LGG associated with an IDH1-mutated LGG cohort and using the features to predict high-risk patients from the IDH1-wildtype cohort. This ANN model facilitates the selection of LGG patients who could benefit from immediate adjuvant radiotherapy. Future work includes the integration of image features to improve the prediction performance of the GlioPredictor system.

SLE pachymeningitis and multiple cranial nerve palsies: a case report and review of the literature

Hypertrophic pachymeningitis (HP) is a relatively uncommon disease associated with focal or diffuse thickening of the dura mater secondary to underlying chronic inflammation. The link between systemic lupus erythematosus (SLE) and hypertrophic pachymeningitis (HP) is extremely rare, with only six other cases reported in the literature. We, however, report the first case of SLE pachymeningitis presenting with multiple cranial nerve palsies. The patient showed good response to steroids and cyclophosphamide therapy. One should maintain a high index of suspicion to make the diagnosis in patients with SLE presenting with neurological dysfunction. Prompt therapy prevents long-term neurological sequelae.

Spatial and temporal characteristics of ambient atmospheric hydrocarbons in an active shale gas region in North Texas

Over the past decade, significant development in shale gas extraction technologies has led to a massive increase in oil and gas production within the Barnett Shale region in North Texas. This region abuts a fast-growing Dallas-Fort Worth urban area with increasing air quality concerns. Air quality information for 2011-2015 from two urban and three non-urban monitoring sites within the Barnett Shale region were analyzed to identify the spatial and temporal trends of volatile organic compounds (VOC) concentrations. The non-urban sites had higher mean concentrations of total non-methane organic compounds (TNMOC) at 123.6 ppb-C than 77.06 ppb-C at the urban sites. Alkanes, which includes ethane, propane and n-butane, were the dominant VOC group at all five monitoring sites, with 88% of TNMOC at urban sites and 95% at the non-urban sites. Alkenes, alkynes and aromatics composition at urban sites accounted for 3.96%, 0.72% and 4.72% of TNMOC, and at the non-urban sites these were 1.55%, 0.43% and 1.94%, respectively. Seasonal variations were noted in the VOC profiles with high concentrations during the winter months and low during summer months. The alkane/TNMOC ratio also showed a similar seasonal pattern, with a median value of 0.8 at the urban sites and 0.9 at non-urban sites. Alkene/TNMOC ratios were highest during the summer months, while alkyne/TNMOC ratios were highest during spring and low in winter, due to the influence of localized urban emissions. Higher concentrations of isoprene were measured at one of the urban sites as a result of biogenic emissions from nearby urban forests. Spatial and temporal analysis of measured VOC concentrations at ambient air monitoring stations in North Texas revealed strong influence of source regions with high oil and gas activities in close proximity.

Medical Literature Searches -How Many Bibliographic Databases are Needed for Sufficient Retrieval in Medical Topics?

As many bibliographic services in medicine are offered, literature searches in eight databases at DIMDI were performed to find out which database is most important in medicine. The distribution of publications from members of the medical faculty of Frankfurt University was examined. No save prediction is possible as to which database will yield most articles. Overlapping from different databases is often rather low. The selection of an appropriate database mix for sufficient recall and in a cost-effective manner.is a task for an experienced searcher.

Disseminated cerebral toxoplasmosis in a patient with chronic lymphocytic leukemia

Infections are one of the most common causes of mortality in immunocompromised patients. In patients diagnosed with hematologic malignancies, treatment with stem cell transplants (SCT) or T-cell suppressing chemotherapy increases the risk of central nervous system (CNS) infections, of which toxoplasmosis is the most common. We report the case of a 63 year-old woman with chronic lymphocytic leukemia (CLL) that presented with gait instability and visual changes. Intracranial lesions were noted on initial neuro-imaging. A rapid decline in the patient's mental status warranted an urgent biopsy of the lesions that revealed tachyzoites consistent with toxoplasmosis. In the presence of diffuse brain lesions that lack a metastatic pattern or contrast enhancement, a common approach is to perform biopsy only after a battery of non-invasive testing. This diagnostic delay may take several days, exposing the patient to a rapidly fatal infection. This report illustrates the utility of early brain biopsy in high-risk patients with hematologic malignancies and CNS lesions.

The Consensus from the Mycobacterium avium ssp. paratuberculosis (MAP) Conference 2017

On March 24 and 25, 2017 researchers and clinicians from around the world met at Temple University in Philadelphia to discuss the current knowledge of Mycobacterium avium ssp. paratuberculosis (MAP) and its relationship to human disease. The conference was held because of shared concern that MAP is a zoonotic bacterium that poses a threat not only to animal health but also human health. In order to further study this problem, the conferees discussed ways to improve MAP diagnostic tests and discussed potential future anti-MAP clinical trials. The conference proceedings may be viewed on the www.Humanpara.org website. A summary of the salient work in this field is followed by recommendations from a majority of the conferees.

Statistical evaluation of the impact of shale gas activities on ozone pollution in North Texas

Over the past decade, substantial growth in shale gas exploration and production across the US has changed the country's energy outlook. Beyond its economic benefits, the negative impacts of shale gas development on air and water are less well known. In this study the relationship between shale gas activities and ground-level ozone pollution was statistically evaluated. The Dallas-Fort Worth (DFW) area in north-central Texas was selected as the study region. The Barnett Shale, which is one the most productive and fastest growing shale gas fields in the US, is located in the western half of DFW. Hourly meteorological and ozone data were acquired for fourteen years from monitoring stations established and operated by the Texas Commission on Environmental Quality (TCEQ). The area was divided into two regions, the shale gas region (SGR) and the non-shale gas (NSGR) region, according to the number of gas wells in close proximity to each monitoring site. The study period was also divided into 2000-2006 and 2007-2013 because the western half of DFW has experienced significant growth in shale gas activities since 2007. An evaluation of the raw ozone data showed that, while the overall trend in the ozone concentration was down over the entire region, the monitoring sites in the NSGR showed an additional reduction of 4% in the annual number of ozone exceedance days than those in the SGR. Directional analysis of ozone showed that the winds blowing from areas with high shale gas activities contributed to higher ozone downwind. KZ-filtering method and linear regression techniques were used to remove the effects of meteorological variations on ozone and to construct long-term and short-term meteorologically adjusted (M.A.) ozone time series. The mean value of all M.A. ozone components was 8% higher in the sites located within the SGR than in the NSGR. These findings may be useful for understanding the overall impact of shale gas activities on the local and regional ozone pollution.

Resolution of Crohn's disease and complex regional pain syndrome following treatment of paratuberculosis

A cohort of family members with various chronic diseases including Crohn's disease, asthma, complex regional pain syndrome, hypothyroidism, type 1 diabetes mellitus, and lymphangiomatosis and/or evidence of infection by Mycobacterium avium subsp. paratuberculosis (MAP) are described in this series of case reports. MAP was cultured from the blood of three members affected by the first five diseases and there was accompanying elevated anti-MAP IgG in two members. The patient affected by the sixth disease has a markedly elevated anti-MAP titer. The two patients affected by the first four diseases have been treated with a combination of anti-MAP antibiotics and ultraviolet blood irradiation therapy with resolution of the disease symptomatology and inability to culture MAP in post treatment blood samples. These case reports of patients with MAP infections provide supportive evidence of a pathogenic role of MAP in humans.

Spinal subdural abscess following epidural steroid injection

The authors report the case of a 58-year-old man who presented with a cervicothoracolumbosacral spinal subdural abscess about a month after receiving an epidural steroid injection for management of low-back pain due to L5-S1 disc herniation. Although he presented with symptoms concerning for a spinal etiology, the subdural empyema was not evident on the initial MRI study and was observed on imaging 5 days later. This patient was successfully managed with surgical intervention and antibiotic treatment, and he is doing well more than 21 months after the operation. It is possible that a prior history of disc herniation or other spinal abnormality may increase a patient's risk of developing spinal subdural empyema. This case illustrates the risk of infection following spinal epidural steroid injections and the importance of early recognition and intervention to successfully treat an extensive subdural abscess.

Seroprevalence of bluetongue among domestic ruminants in Northern Kerala, India

The objective of the present study is to assess the seroprevalence of bluetongue (BT) among domestic ruminants of Northern Kerala. Sera samples from cattle (82), goat (40) and sheep (50) collected from districts of Wayanad, Kozhikode and Palakkad respectively were tested using competitive enzyme linked immune-sorbent assay (cELISA). Out of the 172 samples tested, the overall BT seroprevalence was 9.3%. There is an increase in prevalence from previous reports which may indicate possible outbreaks in future.

Increased plasma levels of CK-18 as potential cell death biomarker in patients with HELLP syndrome

HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome represents a life-threatening pregnancy disorder with high fetal and maternal mortality, but its underlying molecular mechanisms remain unknown. Although apoptosis has been implicated in HELLP syndrome, its pathogenic role remains largely unclear. In the present study, we investigated whether the detection of apoptosis by novel plasma biomarkers is of diagnostic value in HELLP patients. For this purpose, we analyzed two biomarkers that specifically detect apoptosis or overall cell death of epithelial cells, such as hepatocytes or placental trophoblasts, through the release of caspase-cleaved or total (caspase-cleaved and uncleaved) cytokeratin-18 (CK-18) in plasma of HELLP patients compared with pregnant as well as non-pregnant healthy women. In addition, caspase activation and cell death were determined in placental tissues of HELLP patients and individuals with normal pregnancy. In contrast to pregnant or non-pregnant healthy controls, we observed significantly increased levels of both caspase-cleaved and total CK-18 in plasma of HELLP patients. Following delivery, CK-18 levels rapidly decreased in HELLP patients. Caspase activation and cell death were also elevated in placental tissues from HELLP patients compared with healthy pregnant women. These data demonstrate not only that apoptosis is increased in HELLP syndrome, but also that caspase-cleaved or total CK-18 are promising plasma biomarkers to identify patients with HELLP syndrome. Thus, further studies are warranted to evaluate the utility of these biomarkers for monitoring disease activity in HELLP syndrome.

Dural venous sinus thrombosis in anaplastic astrocytoma following concurrent temozolomide and focal brain radiotherapy plus bevacizumab

Malignant gliomas have long been a therapeutic dilemma in neuro-oncology, with a poor overall prognosis. Standard treatment, consisting of primary resection, followed by radiation therapy and temozolomide, has improved prognosis. Recently, studies have looked at the addition of bevacizumab (Avastin), a humanized murine IgG1 monoclonal antibody against vascular endothelial growth factor-A, to conventional regiments. Bevacizumab gained US FDA approval for single agent use in recurrent glioblastoma in 2009. Known side effects of bevacizumab include increased risk of arterial and venous thromboembolism, as well as hemorrhage. With emerging data for the use of bevacizumab in malignant gliomas, the extent of risks such as bleeding and thrombosis in patients with primary brain tumors treated with bevacizumab remains unknown. Here, we present only the second reported case of dural venous sinus thrombosis during treatment with bevacizumab and the first reported case for a primary glioma treated with temozolomide, radiation, and bevacizumab.

Seasonal variations in the levels of PAH-DNA adducts in young adults living in Mexico City

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous components of polluted air. The Mexico City Metropolitan Area (MCMA), one of the most densely populated areas in the world, is 2240 m above sea level. At this altitude, less oxygen is available, making combustion less efficient and therefore producing more PAH pollutants. According to the Automatic Monitoring Network in Mexico City (RAMA, for its Spanish initials; http://www.sma.df.gob.mx/simat2/informaciontecnica/index.php?opcion=5&opciondifusion_bd=90), which performs environmental monitoring, the critical air pollutants in Mexico City are ozone and particulate matter (PM). PM emissions increase during the dry season (winter to spring) and decrease during the rainy season (summer to autumn). The bioactivation of some PAHs produces reactive metabolites that bind to DNA, and the presence of elevated levels of PAH-DNA adducts in tissues such as blood lymphocytes represents an elevated risk for the development of cancer. We have compared the levels of PAH-DNA adducts and the percentage of cells with chromosomal aberrations (CWAs) using a matched set of peripheral blood lymphocytes obtained on two separate occasions from young non-smoking inhabitants of the MCMA (n = 92) during the 2006 dry season and the following rainy season. PAH-DNA adducts were analysed using the r7, t8-dihydroxy-t-9, 10-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE)-DNA chemiluminescence immunoassay (CIA). The percentages of CWA were determined in cultured lymphocytes from the same individuals. Both DNA adduct levels and chromosomal aberrations were tested for correlation with lifestyle and the polymorphisms of cytochromes P450 CYP1A1 and CYP1B1 as well as glutathione-S-transferases GSTM1 and GSTT1. The levels of PAH-DNA adducts were significantly higher (P < 0.001) in the dry season (10.66 ± 3.05 per 10(9) nt, n = 92) than during the rainy season (9.50 ± 2.85 per 10(9) nt, n = 92) and correlated with the seasonal levels of particulate matter with a diameter of ≤ 10 μm (PM(10)). The percentage of CWA was not seasonally related; however, significant associations between the number of risk alleles and adduct levels in the dry (R = 0.298, P = 0.048) and in the wet seasons (R = 0.473, P = 0.001) were observed.

Nuclear bud formation: a novel manifestation of Zidovudine genotoxicity

Normal diploid somatic mammalian cell division generates 2 daughter cells as a result of a strict and well-controlled mitotic process. However, some defects during the progression of that process could generate an unbalanced distribution of chromosomes, aneuploidy and eventually, a malignant phenotype. Previous observations using a transgenic mouse model with diminished DNA repair capacity revealed the presence of nuclear buds (NBs) induced in vitro by the nucleoside analog zidovudine (Retrovir(R), 3'-azido-3'-deoxythymidine, AZT). Here we used bone marrow mesenchymal cells, taken from mice with the Xpa(-/-)Trp53(+/-) genotype, that were cultured and exposed to 0 and 100 muM AZT for 24 hours. Fixed and denatured cells were processed by fluorescence in situ hybridization (FISH) with whole chromosome painting probes used to identify chromosomes in cells growing on glass chamber slides (2 probes/slide). A variety of sizes and shapes of NBs were observed. Some NBs had a large connection with the main nucleus (>(1/4) of the NB diameter), others hada smaller connection (<(1/4) of the NB diameter), some were circular and positioned close to the nucleus, while some resided in the cytoplasm separated from the nucleus or connected by a thin chromatin strand. We had hypothesized that NBs would progress in the process of budding until separation occurred, but this was not proven by time-lapse photography studies performed for 20 hours. From 1,126 cells scored in the unexposed cultures, 10.39 % of cells carried NBs, while from 1,108 cells scored in the AZT-exposed cultures 29.16% of cells carried NBs (p = 0.001). In AZT-exposed cells there were a total of 322 NBs scored; 46.6% or 150 NBs contained positive signals for one or both probes used, while 53% or 172 NBs had no probe signal. In addition, FISH analysis showed no preferential localization of any chromosome within the NBs. Among the NBs that carried no probe signal, the presence of positive signals with inversion of DAPI imaging demonstrated centromeric content. It has been hypothesized that NBs occur as a result of expulsion of amplified DNA from the main nucleus; however, this data demonstrates that NBs may contain any chromosome, suggesting that NBs do not consist of just amplified DNA.

Source characterization of volatile organic compounds affecting the air quality in a coastal urban area of South Texas

Selected Volatile Organic Compounds (VOC) emitted from various anthropogenic sources including industries and motor vehicles act as primary precursors of ozone, while some VOC are classified as air toxic compounds. Significantly large VOC emission sources impact the air quality in Corpus Christi, Texas. This urban area is located in a semi-arid region of South Texas and is home to several large petrochemical refineries and industrial facilities along a busy ship-channel. The Texas Commission on Environmental Quality has setup two continuous ambient monitoring stations (CAMS 633 and 634) along the ship channel to monitor VOC concentrations in the urban atmosphere. The hourly concentrations of 46 VOC compounds were acquired from TCEQ for a comprehensive source apportionment study. The primary objective of this study was to identify and quantify the sources affecting the ambient air quality within this urban airshed. Principal Component Analysis/Absolute Principal Component Scores (PCA/APCS) was applied to the dataset. PCA identified five possible sources accounting for 69% of the total variance affecting the VOC levels measured at CAMS 633 and six possible sources affecting CAMS 634 accounting for 75% of the total variance. APCS identified natural gas emissions to be the major source contributor at CAMS 633 and it accounted for 70% of the measured VOC concentrations. The other major sources identified at CAMS 633 included flare emissions (12%), fugitive gasoline emissions (9%), refinery operations (7%), and vehicle exhaust (2%). At CAMS 634, natural gas sources were identified as the major source category contributing to 31% of the observed VOC. The other sources affecting this site included: refinery operations (24%), flare emissions (22%), secondary industrial processes (12%), fugitive gasoline emissions (8%) and vehicle exhaust (3%).

Roadside measurements of ultrafine particles at a busy urban intersection

A field sampling campaign on ultrafine particles (UFPs, diameter <100 nm) was conducted at a busy traffic intersection from December 2006 to June 2007 in Corpus Christi, TX. This traffic intersection consisted of South Padre Island Drive (SPID, Highway 358) and Staples Street. Traffic densities on SPID were 9102/hr and 7880/hr for weekdays and weekends, respectively. Staples Street traffic densities were 2795/hr and 2572/hr, respectively. There were approximately 3.7% heavy-duty diesel vehicles (HDDVs) on both roadways. Peak traffic flows occurred early in the morning and late in the evening during weekdays and around noon on weekends. The average UFP total number concentration collected by a condensation particle counter (CPC 3785; TSI) was 66 x 10(3) cm(-3). A direct relationship between the UFP number concentration and traffic density was observed, but the HDDV traffic density was found to be a better estimator of the UFP number concentration than total traffic density. A scanning mobility particle sizer (SMPS 3936 with DMA 3081 and CPC 3785, TSI) measuring the particle size distribution from 7 to 290 nm was rotated among four corners of the intersection. The upwind and downwind size distributions were both bimodal in shape, exhibiting a nucleation mode at 10-30 nm and a secondary mode at 50-70 nm. The highest and lowest particle concentrations were observed on the downwind and upwind sides of both roadways, respectively, indicating the importance of wind direction. Wind speed also played an important role in overall particle concentrations; UFP concentrations were inversely proportional to wind speed. A negative correlation was observed between particle number concentrations and ambient temperature. The particle number concentration was 3.5 times greater when traffic was idling at a red light than moving at a green light.

Characterization of fine particulate matter in Ohio: indoor, outdoor, and personal exposures

Ambient, indoor, and personal PM2.5 concentrations were assessed based on an exhaustive study of PM2.5 performed in Ohio from 1999 to 2000. Locations in Columbus, one in an urban corridor and the other in a suburban area were involved. A third rural location in Athens, Ohio, was also established. At all three locations, elementary schools were utilized to determine outdoor, indoor, and personal PM2.5 concentrations for fourth and fifth grade students using filter-based measurements. Three groups of 30 students each were used for personal sampling at each school. Continuous ambient PM2.5 mass concentrations were also measured with tapered element oscillating microbalances (TEOMs). At all three sites, personal and indoor PM2.5 concentrations exceeded outdoor levels. This trend is consistent on all week days and most evident in the spring as compared to fall and winter. The ambient PM2.5 concentrations were similar among the three sites, suggesting the existence of a common regional source influence. At all the three sites, larger variations were found in personal and indoor PM2.5 than ambient levels. The strongest correlations were found between indoor and personal concentrations, indicating that personal PM2.5 exposures were significantly affected by indoor PM2.5 than by ambient PM2.5. This was further confirmed by the indoor to outdoor (I/O) ratios of PM2.5 concentrations, which were greater when school was in session than non-school days when the students were absent.

Brain death: a challenging diagnosis in trauma patients

Brain death is a catastrophic consequence of trauma, and diagnosing it can be a challenging for physicians because it presents in numerous ways. Since existing recommendations are not applicable to all hospitals because of the requirement of special equipment and highly-trained personnel, a committee of health care professionals at Charleston Area Medical Center in Charleston decided to review the available literature and create a new set of protocols regarding brain death. This article summarizes the findings of the committee and provides recommendations for physicians working with trauma patients.

Analysis of trace elements and ions in ambient fine particulate matter at three elementary schools in Ohio

The results from a chemical characterization study of fine particulate matter (PM2.5) measured at three elementary schools in Central and Southeast Ohio is presented here. PM2.5 aerosol samples were collected from outdoor monitors and indoor samplers at each monitoring location during the period of February 1, 1999, through August 31, 2000. The locations included a rural elementary school in Athens, OH, and two urban schools within Columbus, OH. The trace metal and ionic concentrations in the collected samples were analyzed using an X-ray fluorescence spectrophotometer and ion chromatography unit, respectively. Sulfate ion was found to be the largest component present in the samples at all three of the sites. Other abundant components included nitrate, chloride, ammonium, and sodium ions, as well as calcium, silicon, and iron. The average PM2.5 concentrations showed similar temporal variations among the three sites within the study region. PM2.5 and its major component, sulfate ion, showed strong seasonal variations with maximum concentrations observed during the summer at all three of the sites. The indoor environment was found to be more contaminated during the spring months (March through May) at New Albany (a suburb of Columbus, OH) and East Athens (rural Ohio area). Potential source contribution function analysis showed that particulate matter levels at the monitoring sites were affected by transport from adjoining urban areas and industrial complexes located along the Ohio River Valley. A preliminary outdoor source apportionment using the principal component analysis (PCA) technique was performed. The results from the PCA suggest that the study region was primarily impacted by industrial, fossil fuel combustion, and geological sources. The 2002 emissions inventory data for PM2.5 compiled by Ohio Environmental Protection Agency also showed impacts of similar source types, and this was used to validate the PCA analysis.

Self-propelled running droplets on solid substrates driven by chemical reactions

We study chemically driven running droplets on a partially wetting solid substrate by means of coupled evolution equations for the thickness profile of the droplets and the density profile of an adsorbate layer. Two models are introduced corresponding to two qualitatively different types of experiments described in the literature. In both cases an adsorption or desorption reaction underneath the droplets induces a wettability gradient on the substrate and provides the driving force for droplet motion. The difference lies in the behavior of the substrate behind the droplet. In case I the substrate is irreversibly changed whereas in case II it recovers allowing for a periodic droplet movement (as long as the overall system stays far away from equilibrium). Both models allow for a non-saturated and a saturated regime of droplet movement depending on the ratio of the viscous and reactive time scales. In contrast to model I, model II allows for sitting drops at high reaction rate and zero diffusion along the substrate. The transition from running to sitting drops in model II occurs via a super- or subcritical drift-pitchfork bifurcation and may be strongly hysteretic implying a coexistence region of running and sitting drops.

The regional nature of PM2.5 episodes in the upper Ohio River Valley

From October 1999 through September 2000, particulate matter (PM) with aerodynamic diameter > or =2.5 microm (PM2.5) mass and composition were measured at the National Energy Technology Laboratory Pittsburgh site, with a particle concentrator Brigham Young University-organic sampling system and a tapered element oscillating microbalance (TEOM) monitor. PM2.5 measurements had also been obtained with TEOM monitors located in the Pittsburgh, PA, area, and at sites in Ohio, including Steubenville, Columbus, and Athens. The PM data from all these sites were analyzed on high PM days; PM2.5 TEOM particulate mass at all sites was generally associated with transitions from locally high barometric pressure to lower pressure. Elevated concentrations occurred with transport of PM from outside the local region in advance of frontal passages as the local pressure decreased. During high-pressure periods, concentrations at the study sites were generally low throughout the study region. Further details related to this transport were obtained from surface weather maps and estimated back-trajectories using the hybrid single-particle Lagrangian integrated trajectory model associated with these time periods. These analyses indicated that transport of pollutants to the Pittsburgh site was generally from the west to the southwest. These results suggest that the Ohio River Valley and possible regions beyond act as a significant source of PM and its precursors in the Pittsburgh area and at the other regional sites included in this study.

Modulation of ATP/ADP concentration at the endothelial surface by shear stress: effect of flow-induced ATP release

The adenine nucleotides ATP and ADP induce the production of vasoactive compounds in vascular endothelial cells (ECs). Therefore, knowledge of how flow affects the concentration of ATP and ADP at the EC surface may be important for understanding shear stress-mediated vasoregulation. The concentration of ATP and ADP is determined by convective and diffusive transport as well as by hydrolysis of these nucleotides by ectonucleotidases at the EC surface. Previous mathematical modeling has demonstrated that for steady flow in a parallel plate flow chamber, the combined ATP+ADP concentration does not change considerably over a wide range of shear stress. This finding has been used to argue that the effect of flow on adenine nucleotide transport could not account for the dependence of endothelial responses to ATP on the magnitude of applied shear stress. The present study extends the previous modeling to include pulsatile flow as well as flow-induced endothelial ATP release. Our results demonstrate that flow-induced ATP release has a pronounced effect on nucleotide concentration under both steady and pulsatile flow conditions. While the combined ATP+ADP concentration at the EC surface in the absence of flow-induced ATP release changes by only approximately 10% over the wall shear stress range 0.1-10 dyne cm(-2), inclusion of this release leads to a concentration change of approximately 34%-106% over the same shear stress range, depending on how ATP release is modeled. These results suggest that the dependence of various endothelial responses to shear stress on the magnitude of the applied shear stress may be partially attributable to flow-induced changes in cell-surface adenine nucleotide concentration.

Arsenic metabolism in seaweed-eating sheep from Northern Scotland

Cation exchange and anion exchange liquid chromatography were coupled to an ICP-MS and optimised for the separation of 13 different arsenic species in body fluids (arsenite, arsenate, dimethylarsinic acid (DMAA), monomethylarsonic acid (MMAA), trimethylarsine oxide (TMAO), tetramethylarsonium ion (TMA), arsenobetaine (AsB), arsenocholine (AsC), dimethylarsinoyl ethanol (DMAE) and four common dimethylarsinoylribosides (arsenosugars). The arsenic species were determined in seaweed extracts and in the urine and blood serum of seaweed-eating sheep from Northern Scotland. The sheep eat 2-4 kg of seaweed daily which is washed ashore on the most northern Island of Orkney. The urine, blood and wool of 20 North Ronaldsay sheep and kidney, liver and muscle from 11 sheep were sampled and analysed for their arsenic species. In addition five Dorset Finn sheep, which lived entirely on grass, were used as a control group. The sheep have a body burden of approximately 45-90 mg arsenic daily. Since the metabolism of arsenic species varies with the arsenite and arsenate being the most toxic, and organoarsenic compounds such as arsenobetaine the least toxic compounds, the determination of the arsenic species in the diet and their body fluids are important. The major arsenic species in their diet are arsenoribosides. The major metabolite excreted into urine and blood is DMAA (95 +/- 4.1%) with minor amounts of MMAA, riboside X, TMA and an unidentified species. The occurrence of MMAA is assumed to be a precursor of the exposure to inorganic arsenic, since demethylation of dimethylated or trimethylated organoarsenic compounds is not known (max. MMAA concentration 259 microg/L). The concentrations in the urine (3179 +/- 2667 microg/L) and blood (44 +/- 19 microg/kg) are at least two orders of magnitude higher than the level of arsenic in the urine of the control sheep or literature levels of blood for the unexposed sheep. The tissue samples (liver: 292 +/- 99 microg/kg, kidney: 565 +/- 193 microg/kg, muscle: 680 +/- 224 microg/kg) and wool samples (10470 +/- 5690 microg/kg) show elevated levels which are also 100 times higher than the levels for the unexposed sheep.

The immune response to Haemophilus ducreyi resembles a delayed-type hypersensitivity reaction throughout experimental infection of human subjects

Previous work in 3 subjects infected for 2 weeks indicated that experimental infection with Haemophilus ducreyi recruits CD4 cells to the skin at the pustular stage of disease. In order to describe the kinetics of the host response, 23 subjects were infected at 2 sites with a standardized dose of H. ducreyi. Subjects were biopsied 1 or 4 days after inoculation or when they developed a painful pustular lesion (days 7-14). Papules and pustules contained a predominant T cell infiltrate that consisted of CD45RO and CD4 cells of the alpha beta lineage. Both papules and pustules contained mixed or T helper 1 type cytokine mRNA and interleukin-8 and tumor necrosis factor-alpha mRNA. Although the subjects had no history of chancroid, their immune responses resembled delayed-type hypersensitivity reactions that occurred within 24 h of inoculation and persisted throughout the course of experimental infection.