A Critical Appraisal of a University's Response to a Campus Mass Shooting: Perspectives from Public Health Students and Researchers at Michigan State University

Mass shootings are a public health crisis and have become more frequent on U.S. university campuses over the past decade, with the number doubling since 2000. Due to this alarming trend, many institutions have developed response strategies for active shooting events. Yet, the extent to which these response strategies address the needs and minimize harm for students, faculty, and staff has not been evaluated critically after a campus mass shooting. Michigan State University (MSU) experienced a mass shooting on February 13, 2023. Before, during, and 6 months following this tragedy, the university employed an estimated 18 strategies to inform, support, and protect its students, faculty, and staff. While MSU continues to address concerns and roll out programs related to this event, here we aimed to (1) create a timeline of resources and communication provided by MSU from the event to 6 months post-event; (2) critically evaluate the extent to which these resources met the needs of students, faculty, and staff through a survey among persons involved in public health research; and (3) identify potential areas for improvement in the university's responses. We used an online survey where participants (n = 10) rated the university responses and provided additional comments. From our survey, we recommend that, in the event of a campus shooting, other universities are attentive to re-engaging with the community within which the university is situated, holding communal events on campus, offering pauses in classes, and enhancing mental health services. These responses were seen as crucial to re-establish campus life and learning.

A systematic review of audit tools for evaluating the quality of green spaces in mental health research

Research showing the relationship between exposure to green space and health has yielded conflicting results, possibly due to the oversight of green space quality in quantitative studies. This systematic review, guided by the PRISMA framework (registered under Prospero ID CRD42023279720), focused on audit tools for green space quality in mental health research. From 4028 studies, 13 were reviewed, with 77 % linking better mental health outcomes to higher green space quality. Eight tools, especially Public Open Space and Dillen et al. tools demonstrated strong correlations with mental health. Certain green space qualities like grass, pathways, and water elements showed positive health associations. Future research should aim for standardized quality metrics and robust methodologies to support causal inferences and efficient assessments.

Systematic review of best practices for GPS data usage, processing, and linkage in health, exposure science and environmental context research

Global Positioning System (GPS) technology is increasingly used in health research to capture individual mobility and contextual and environmental exposures. However, the tools, techniques and decisions for using GPS data vary from study to study, making comparisons and reproducibility challenging.

OBJECTIVES

The objectives of this systematic review were to (1) identify best practices for GPS data collection and processing; (2) quantify reporting of best practices in published studies; and (3) discuss examples found in reviewed manuscripts that future researchers may employ for reporting GPS data usage, processing and linkage of GPS data in health studies.

DESIGN

A systematic review.

DATA SOURCES

Electronic databases searched (24 October 2023) were PubMed, Scopus and Web of Science (PROSPERO ID: CRD42022322166).

ELIGIBILITY CRITERIA

Included peer-reviewed studies published in English met at least one of the criteria: (1) protocols involving GPS for exposure/context and human health research purposes and containing empirical data; (2) linkage of GPS data to other data intended for research on contextual influences on health; (3) associations between GPS-measured mobility or exposures and health; (4) derived variable methods using GPS data in health research; or (5) comparison of GPS tracking with other methods (eg, travel diary).

DATA EXTRACTION AND SYNTHESIS

We examined 157 manuscripts for reporting of best practices including wear time, sampling frequency, data validity, noise/signal loss and data linkage to assess risk of bias.

RESULTS

We found that 6% of the studies did not disclose the GPS device model used, only 12.1% reported the per cent of GPS data lost by signal loss, only 15.7% reported the per cent of GPS data considered to be noise and only 68.2% reported the inclusion criteria for their data.

CONCLUSIONS

Our recommendations for reporting on GPS usage, processing and linkage may be transferrable to other geospatial devices, with the hope of promoting transparency and reproducibility in this research.

PROSPERO REGISTRATION NUMBER

CRD42022322166.

Superfluid Helium Drops Levitated in High Vacuum

We demonstrate the trapping of millimeter-scale superfluid helium drops in high vacuum. The drops are sufficiently isolated that they remain trapped indefinitely, cool by evaporation to 330 mK, and exhibit mechanical damping that is limited by internal processes. The drops are also shown to host optical whispering gallery modes. The approach described here combines the advantages of multiple techniques, and should offer access to new experimental regimes of cold chemistry, superfluid physics, and optomechanics.

Elementary Classroom Views of Nature Are Associated with Lower Child Externalizing Behavior Problems

Exposure to nature views has been associated with diverse mental health and cognitive capacity benefits. Yet, much of this evidence was derived in adult samples and typically only involves residential views of nature. Findings from studies with children suggest that when more greenness is available at home or school, children have higher academic performance and have expedited attention restoration, although most studies utilize coarse or subjective assessments of exposure to nature and largely neglect investigation among young children. Here, we investigated associations between objectively measured visible nature at school and children's behavior problems (attention and externalizing behaviors using the Brief Problem Monitor Parent Form) in a sample of 86 children aged seven to nine years old from 15 classrooms across three schools. Images of classroom windows were used to quantify overall nature views and views of specific nature types (sky, grass, tree, shrub). We fitted separate Tobit regression models to test associations between classroom nature views and attention and externalizing behaviors, accounting for age, sex, race/ethnicity, residential deprivation score, and residential nature views (using Google Street View imagery). We found that higher levels of visible nature from classroom windows were associated with lower externalizing behavior problem scores, after confounder adjustment. This relationship was consistent for visible trees, but not other nature types. No significant associations were detected for attention problems. This initial study suggests that classroom-based exposure to visible nature, particularly trees, could benefit children's mental health, with implications for landscape and school design.

Is water quality in British rivers "better than at any time since the end of the Industrial Revolution"?

We explore the oft-repeated claim that river water quality in Great Britain is "better now than at any time since the Industrial Revolution". We review available data and ancillary evidence for seven different categories of water pollutants: (i) biochemical oxygen demand (BOD) and ammonia; (ii) heavy metals; (iii) sewage-associated organic pollutants (including hormone-like substances, personal care product and pharmaceutical compounds); (iv) macronutrients (nitrogen and phosphorus); (v) pesticides; (vi) acid deposition and (vii) other variables, including natural organic matter and pathogenic micro-organisms. With a few exceptions, observed data are scarce before 1970. However, we can speculate about some of the major water quality pressures which have existed before that. Point-source pollutants are likely to have increased with population growth, increased connection rates to sewerage and industrialisation, although the increased provision of wastewater treatment during the 20th century will have mitigated this to some extent. From 1940 to the 1990s, pressures from nutrients and pesticides associated with agricultural intensification have increased in many areas. In parallel, there was an increase in synthetic organic compounds with a "down-the-drain" disposal pathway. The 1990s saw general reductions in mean concentrations of metals, BOD and ammonia (driven by the EU Urban Waste Water Treatment Directive), a levelling out of nitrate concentrations (driven by the EU Nitrate Directive), a decrease in phosphate loads from both point-and diffuse-sources and some recovery from catchment acidification. The current picture is mixed: water quality in many rivers downstream of urban centres has improved in sanitary terms but not with respect to emerging contaminants, while river quality in catchments with intensive agriculture is likely to remain worse now than before the 1960s. Water quality is still unacceptably poor in some water bodies. This is often a consequence of multiple stressors which need to be better-identified and prioritised to enable continued recovery.

Quantum Optomechanics in a Liquid

We measure the quantum fluctuations of a single acoustic mode in a volume of superfluid He that is coupled to an optical cavity. Specifically, we monitor the Stokes and anti-Stokes light scattered by a standing acoustic wave that is confined by the cavity mirrors. The intensity of these signals (and their cross-correlation) exhibits the characteristic features of the acoustic wave's zero-point motion and the quantum backaction of the intracavity light. While these features are also observed in the vibrations of solid objects and ultracold atomic gases, their observation in superfluid He opens the possibility of exploiting the remarkable properties of this material to access new regimes of quantum optomechanics.

Long-term experiments to investigate irreversibility in sorption of pesticides to soil

Experiments investigated irreversibility in pesticide sorption to soil. Sorption behaviour under abiotic conditions was quantified for chlorotoluron, prometryn and hexaconazole in three soils over periods of up to 274 days. An isotope-exchange procedure was used whereby sorption of (12)C- and (14)C-pesticide isotopes in shaken suspensions of three soils (56-168 days shaking) was followed by substitution of the isotopes in the liquid phase and a 14-day exchange phase. This was followed by forced isotope exchange where the sorbed (14)C material was exchanged by adding an excess of non-radiolabelled compound. Experiments were concluded with solvent extraction and soil combustion to determine remaining radioactivity. Under conditions of continuous shaking, the pesticide-soil systems took around four months to approach sorption equilibrium, resulting in strong asymmetry between the profiles of exchange for isotopes of all three compounds. Physically entrapped residues were released back into solution under the steep concentration gradient of forced isotope exchange and small amounts of radioactivity were still being released at the termination of the experiment. The profiles of exchange did not deviate markedly from ideal behaviour based on the assumption that sorption is fully reversible. Whilst the timescales for release of sorbed residues back into solution were very long, soil combustion at study termination only yielded <1-2% of applied radioactivity; this confirms that sorption processes under abiotic soil conditions were overwhelmingly reversible for this set of compounds and soils.

Use of raw or incubated organic wastes as amendments in reducing pesticide leaching through soil columns

Soil amendment with organic wastes is becoming a widespread management practice since it can effectively solve the problems of uncontrolled waste accumulation and improve soil quality. However, when simultaneously applied with pesticides, organic wastes can significantly modify the environmental behaviour of these compounds. This study evaluated the effect of sewage sludges (SS), grape marc (GM) and spent mushroom substrates (SMS) on the leaching of linuron, diazinon and myclobutanil in packed columns of a sandy soil with low organic matter (OM) content (<1%). Soil plus amendments had been incubated for one month (1 m) or 12 months (12 m). Data from the experimental breakthrough curves (BTCs) were fitted to the one-dimensional transport model CXTFIT 2.1. All three amendments reduced leaching of linuron and myclobutanil relative to unamended soil. SMS was the most effective in reducing leaching of these two compounds independent of whether soil was incubated for 1 m or 12 m. Soil amendments increased retardation coefficients (Rexp) by factors of 3 to 5 for linuron, 2 to 4 for diazinon and 3 to 5 for myclobutanil relative to unamended soil. Leaching of diazinon was relatively little affected by soil amendment compared to the other two compounds and both SS and SMS amendment with 1m incubation resulted in enhanced leaching of diazinon. The leaching data for linuron and myclobutanil were well described by CXTFIT (mean square error, MSE<4.9·10(-7) and MSE<7.0·10(-7), respectively) whereas those of diazinon were less well fitted (MSE<2.1·10(-6)). The BTCs for pesticides were similar in soils incubated for one month or one year, indicating that the effect of amendment on leaching persists over relatively long periods of time.

Sensitivity analysis for the SimpleTreat model to simulate fate of chemicals in sewage treatment plants

SimpleTreat 3.1 predicts the distribution and elimination of chemicals by sewage treatment. The model is used as the default calculation in EUSES 2.0 to estimate exposure concentration in the receiving water, soil and air. A sensitivity analysis was performed to rank input parameters according to their influence on model predictions. Triclosan was selected for the base case. The sewage flow, degradation rates and parameters describing the raw sewage were shown to be the most sensitive inputs. The pH and dissociation constant are very sensitive parameters when working with ionisable compounds. Variation in certain input parameters was propagated through the model to yield greater variation in output parameters with a maximum ratio of 4.0. SimpleTreat 3.1 is a steady state model describing a highly non-steady system. A large variability in the most sensitive parameters is expected within a single sewage plant and parameters should therefore be selected to cover this variability.

Anxiety and cardiovascular symptoms: the modulating role of insomnia

BACKGROUND

Anxiety and insomnia are associated with cardiovascular (CV) symptoms. We assessed whether the relation between anxiety and CV symptoms is modulated by insomnia.

METHODS

Independently living women (n = 1,440; mean age = 59.36 +/- 6.53 years) were recruited by cluster sampling technique. We obtained data on demographic characteristics, health beliefs, access to health care, CV symptoms, sleep, stress and anxiety levels.

RESULTS

Overall, 56% of the sample reported insomnia; 46% reported CV symptoms, and 54% were highly anxious. There was a greater likelihood for highly anxious women and those experiencing insomnia to report CV symptoms (r(s) = 0.31* and r(s) = 0.32*, respectively). In logistic regression analysis, the adjusted odds ratios for reporting CV symptoms were 1.39 for patients with insomnia and 2.79 for those with anxiety. With control for insomnia, we observed a 3-fold reduction in the magnitude of the association between anxiety and CV symptoms (r(p) = 0.09*). Stepwise adjustments for sociodemographic factors, CV risk markers, and factors anchoring health beliefs and access to health care showed lesser impact on the relationships. With simultaneous control for those covariates, the correlation was r(p) = 0.13*; * p < 0.01.

CONCLUSION

The association of CV symptoms with anxiety is partly accounted for by insomnia.

The kinetics of sorption by retarded diffusion into soil aggregate pores

This study investigates time-dependent sorption of pesticides in soil aggregates. We tested if the sorption kinetics of pesticides in soil aggregates can be described by modeling diffusion into aggregates for a range of soils and pesticides. Our hypothesis is that the rate of sorption is negatively related to sorption strength due to retardated diffusion. Natural aggregates of 3-5 mm diameter were separated from three soils: a clay, a silty clay loam, and a clay loam. The aggregates were stabilized with alginate gel, and adsorption of azoxystrobin, chlorotoluron, and atrazine was measured in batch experiments with eight equilibration times up to 28 days. Equilibrium sorption appeared to be reached within the 28-day period for each pesticide. An intra-aggregate diffusion model was employed to describe the increase of sorption with time. The model describes diffusion of the dissolved pesticides through the pore space inside the aggregates and sorption on internal surfaces. Sorption could be described by pore diffusion into the aggregates with diffusion coefficients between 0.5 x 10(-10) and 1.5 x 10(-10) m(2) s(-1). The model fits support the theory that pore diffusion is the rate-limiting process for sorption of pesticides in aggregates, although the diffusion coefficients were a factor 3-10 smaller than the theoretical diffusion coefficient for diffusion in water. Comparing the results from the different pesticide-soil combinations showed that the extent of nonequilibrium increased with increasing sorption strength. This confirmed that sorption takes longer to reach equilibrium for pesticides and soils with stronger sorption. The differences between the different pesticides and soils were fully accounted for in the model by stronger retardation of the more strongly sorbed pesticides. The results imply that diffusion into aggregates may be the major time-limiting process for sorption of pesticides in structured soils. Commonly performed sorption experiments with sieved soil fail to account for this process.

Remediation of waters contaminated with ionic herbicides by sorption on polymerin

This study investigated the sorption of paraquat and 2,4-D on polymerin, the humic acid-like fraction of olive mill wastewater. Effects of pH, contact time, initial concentration and sorbent dosage on the sorption of both herbicides were studied. The sorption mechanism of paraquat on polymerin was consistent with the ion exchange of this herbicide with Ca, Mg and K natively occurring in the sorbent; in contrast, 2,4-D was bound to polymerin by hydrogen bonding. Simulated wastewaters contaminated with paraquat were purified after three sorption cycles on polymerin renewed at each cycle, at a solid/liquid ratio of 0.5, whereas those containing 2,4-D showed a maximal residue removal of 44% after two sorption cycles at the same ratio. The possible application of this model to other water-soluble herbicides, as well as the possible exploitation of polymerin as a bio-filter for the decontamination of pollution point sources is briefly discussed.

Changes in pesticide adsorption with time at high soil to solution ratios

Adsorption of six pesticides (2,4-D, dicamba, fluroxypyr, fluazifop-P, metsulfuron-methyl and flupyrsulfuron-methyl) in nine contrasting soils was measured using two techniques: (i) a classical batch method and (ii) a centrifugation method that allowed the measurement of adsorption at a realistic soil to solution ratio after one and seven days. Although the batch method gived significantly higher values of Kd than the centrifugation method for the more strongly sorbed molecules in the more sorptive soils, it tended to give lower adsorption coefficients compared to the centrifugation method when adsorption was lower. Discrepancies between the two methods were probably mainly due to the vigorous shaking applied in the batch technique that artificially enhances the availability of adsorption sites. This implies that shortly after application, more pesticide may be present in the soil solution and thus be available for degradation, plant uptake or leaching than will be predicted from adsorption coefficient determined using the batch method. Adsorption significantly increased between one and seven days and the extractability of total residues decreased with time. The increase in adsorption was not directly related to the level of adsorption although it was more important in soils containing more organic carbon (p=0.022). These results confirm the importance of time-dependent processes and the necessity to include them in risk assessment procedures. The centrifugation technique is a useful method to measure adsorption of pesticides at realistic soil moisture contents and seems to be an adequate technique to characterise the fraction of pesticide that is available for leaching at a given time after application.

Adsorption of ionisable pesticides in soils

Understanding the fate of a pesticide in soil is fundamental to the accurate assessment of its environmental behaviour and vital in ensuring the safe use of new and existing products. Ionisable pesticides comprise a significant proportion of both existing and new active substances registered for use in agriculture worldwide. This group of pesticides includes chemicals that are frequently found in groundwater and surface waters in many different countries. Despite this, approaches to predict the influence of soil properties on the behaviour of ionisable pesticides in soils are poorly developed. Current regulatory assessments frequently default to methods developed for nonionic chemicals, although it is evident that ionisable compounds do not often react like neutral molecules. This review presents the state of knowledge on the adsorption of ionisable pesticides in soils. It first introduces the issues concerning adsorption and the characteristics of this particular kind of chemical. The mechanisms postulated for the adsorption of ionisable pesticides are then described: these are hydrophobic partitioning, ionic exchange, charge transfer, ligand exchange, cation or water bridging, and the formation of bound residues. Relatively little experimental evidence is available, and we are still unable to determine the quantitative contribution of each process in a particular situation. Knowledge is still lacking concerning phenomena occurring at the surfaces of soil particles. Measurements do not allow determination of the operative pH at the surface of soil particles or in microenvironments, and the influence of ionic strength or competition effects is difficult to assess. Subsequently, the review focuses on the influence of soil properties on adsorption and on potential to predict the behaviour of ionisable pesticides in soils. Unlike hydrophobic compounds, adsorption of ionisable pesticides is highly sensitive to variation in pH. This relationship mainly derives from the different proportion of ionic and neutral forms of the pesticide present at each pH level but also from the presence of surfaces with pH-dependent charges in soils. Soil organic matter generally promotes adsorption, although a negative influence has sometimes been reported. Clay and oxides can also play a significant role in some cases. So far, no modelling approach has been applied successfully to a range of ionisable pesticides to predict their adsorption in soils. The standardization of experimental settings and the application of approaches specific to a particular class of pesticide or different type of soil might be necessary to describe the complexity of interactions among ionisable molecules. Degradation of ionisable pesticides is influenced by soil pH in a particular way that relates to changes in sorption, changes in composition and activity of the microbial community, and to shifts in the balance between different degradative mechanisms.

Clinical assessment of near-infrared spectroscopy for noninvasive diabetes screening

BACKGROUND

Current diabetes screening techniques comprise the fasting plasma glucose (FPG) and oral glucose tolerance tests. Both tests demand patient compliance, and neither test has ideal performance. Near-infrared (NIR) spectroscopy is a noninvasive means of interrogating characteristics of a sample and is evaluated as a novel screening method for type 2 diabetes.

METHODS

One hundred fifty-four patients with and without type 2 diabetes were recruited. Their forearm skin was measured with the NIR spectroscopic system, and a capillary blood glucose measurement was also taken. Sixty-six patients returned for a second visit at a later date. A multivariate model, generated from a separate training study, was employed to produce a quantitative risk marker of disease for each NIR spectrum. Sensitivity and specificity (the probabilities that the NIR method will correctly identify a subject as having diabetes or as not having diabetes, respectively) were calculated. As the NIR method produces a continuous rather than categorical classification, various thresholds were evaluated to give several sensitivity and specificity pairs. Test reproducibility was also determined.

RESULTS

At a false-positive rate of 70%, the NIR test had a sensitivity of 77.7%, which is comparable to the 77.3% sensitivity for the FPG test as reported for the Third National Health and Nutrition Examination Survey (NHANES III) study. The reproducibility of the NIR test was also similar to the FPG test (inter-day agreement rates of 84.2% and 79.2%, respectively).

CONCLUSIONS

A noninvasive NIR spectroscopic measurement of the volar forearm was shown to have comparable performance characteristics with the FPG test. The source of the spectroscopic signal is still uncertain and is the subject of ongoing research.

Noninvasive alcohol testing using diffuse reflectance near-infrared spectroscopy

A diffuse reflectance near-infrared (NIR) spectrometer was evaluated as a noninvasive alternative to breath and blood measurements for in vivo alcohol testing. A hybrid partial least squares (PLS) calibration was constructed using a combination of in vivo and in vitro spectral data. This model was subsequently evaluated for its performance in quantifying alcohol concentrations in vivo using a prospective validation study involving subjects who did not participate in the calibration. The validation study entailed induction of alcohol excursions in ten human subjects and comparison of the noninvasive NIR alcohol measurements to blood and breath alcohol measurements. Blood and breath alcohol measurements were performed at the time of each noninvasive NIR measurement (N = 372), establishing the noninvasive NIR measurement standard error relative to blood alcohol at 4.9 mg/dL (0.0049%). Assessment of the hybrid calibration model's sensitivity and selectivity provided strong evidence that the hybrid calibration yielded measurements that were both sensitive to alcohol and independent of other absorbing analytes in human tissue.

A lysimeter experiment to investigate temporal changes in the availability of pesticide residues for leaching

Leaching of three pesticides (isoproturon, chlorotoluron and triasulfuron) and a tracer (bromide) were determined in four contrasting soils ranging in texture from sandy loam to clay. The compounds were applied to undisturbed columns of soil and four columns for each soil were randomly selected and leached with 24-mm equivalent of water at prescribed time intervals (3, 9, 24, 37 and 57 d after application). A rapid decline in leached loads of isoproturon and chlorotoluron as time from application to irrigation increased was observed in all soils. In contrast, triasulfuron and bromide loads only decreased rapidly in the clay soil. Bromide losses decreased with decreasing clay contents of the soil and therefore with a decrease in structural development. Magnitudes of pesticide losses varied from soil to soil, depending on structural development and the organic carbon content. Pesticide degradation experiments on disturbed and undisturbed soil samples showed that the rapid decline of leached loads with time was faster than could be explained by degradation alone. Five physico-chemical processes are put forward to explain the different patterns of pesticide leached loads observed in the soils: (1) relative extent of preferential flow, (2) sorption capacity of the compounds to the different soils, (3) extent of degradation of the compounds in the soil, (4) variation in sorption kinetics between compounds associated with pesticide diffusion into soil aggregates, and (5) protection of the compounds by a combination of intra-aggregate diffusion and the presence of preferential flow pathways.

Using a linked soil model emulator and unsaturated zone leaching model to account for preferential flow when assessing the spatially distributed risk of pesticide leaching to groundwater in England and Wales

Although macropore flow is recognized as an important process for the transport of pesticides through a wide range of soils, none of the existing spatially distributed methods for assessing the risk of pesticide leaching to groundwater account for this phenomenon. The present paper presents a spatially distributed modelling system for predicting pesticide losses to groundwater through micro- and macropore flow paths. The system combines a meta version of the mechanistic, dual porosity, preferential flow pesticide leaching model MACRO (the MACRO emulator), which describes pesticide transport and attenuation in the soil zone, to an attenuation factor leaching model for the unsaturated zone. The development of the emulator was based on the results of over 4000 MACRO model simulations. Model runs describe pesticide leaching for the range of soil types, climate regimes, pesticide properties and application patterns in England and Wales. Linking the MACRO emulator to existing spatial databases of soil, climate and compound-specific loads allowed the prediction of the concentration of pesticide leaching from the base of the soil profile (at 1 m depth) for a wide range of pesticides. Attenuation and retardation of the pesticide during transit through the unsaturated zone to the watertable was simulated using the substrate attenuation factor model AQUAT. The MACRO emulator simulated pesticide loss in 10 of 12 lysimeter soil-pesticide combinations, for which pesticide leaching was shown to occur and also successfully predicted no loss from 3 soil-pesticide combinations. Although the qualitative aspect of leaching was satisfactorily predicted, actual pesticide concentrations in leachate were relatively poorly predicted. At the national scale, the linked MACRO emulator/AQUAT system was found to predict the relative order of, and realistic regional patterns of, pesticide leaching for atrazine, isoproturon, chlorotoluron and lindane. The methodology provides a first-step assessment of the potential for pesticide leaching to groundwater in England and Wales. Further research is required to improve the modelling concept proposed. The system can be used to refine regional groundwater monitoring system designs and sampling strategies and improve the cost-effectiveness of the measures needed to achieve 'good status' of groundwater quality as required by the Water Framework Directive.

Adsorption and degradation of the weak acid mesotrione in soil and environmental fate implications

The ability of soils to adsorb and degrade pesticides strongly influences their environmental fate. This paper examines the adsorption and degradation of a weak acid, a new herbicide mesotrione 12-[4-(methylsulfonyl)-2-nitrobenzoyl]-1,3-cyclohexanedione], in 15 different soils from Europe and the USA. Experiments were conducted to understand the influence of soil properties, covering a wide range of soil textures, soil pH values (4.4 to 7.5), and organic carbon contents (0.6 to 3.35%). Mesotrione adsorption (Kd values ranged from 0.13 to 5.0 L/kg) was primarily related to soil pH, and to a lesser extent by percent organic carbon (%OC). As soil pH rose. mesotrione Kd values got smaller as mesotrione dissociated from the molecular to anionic form. Mesotrione degradation (half-lives ranged from 4.5 to 32 d) was also related to soil pH, getting shorter as soil pH rose. Simple regression of mesotrione adsorption against soil pH and %OC and against degradation provided a close fit to the data. The correlation between mesotrione adsorption and degradation means that Kd and half-life values are only relevant for use in environmental fate assessment if these values are "paired" for the same soil pH and %OC. The implications were as illustrated for leaching, raising important issues about combining pesticide adsorption and degradation behavior in environmental fate assessments.

Anti-cholinergic bronchodilators versus beta2-sympathomimetic agents for acute exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Inhaled bronchodilators form the mainstay of treatment for acute exacerbations of COPD. Two types of agent are used routinely, either singly or in combination: anticholinergic agents and beta2-sympathomimetic agonists.

OBJECTIVES

To assess the effect of anti-cholinergic agents on lung function and dyspnea in patients with acute exacerbations of COPD, compared with placebo or short-acting beta-2 agonists.

SEARCH STRATEGY

A comprehensive search of the literature was carried out on MEDLINE, EMBASE, CINAHL and the Cochrane COPD Trials Register, using the terms: bronchodilator* OR ipratropium OR oxitropium. References listed in each included trial were searched for additional trial reports.

SELECTION CRITERIA

Studies were included if the participants were adult patients with a known diagnosis of COPD and had symptoms consistent with criteria for acute exacerbation of COPD. All randomized controlled trials that compared inhaled ipratropium bromide or oxitropium bromide to appropriate controls were considered. Appropriate control treatments included placebo, other bronchodilating agents, or combination therapies. Studies of acute asthma or ventilated patients were excluded.

DATA COLLECTION AND ANALYSIS

All trials that appeared to be relevant were assessed by two reviewers who independently selected trials for inclusion. Differences were resolved by consensus.

MAIN RESULTS

Four trials compared the short-term effects of ipratropium bromide vs. a beta2-agonist. Short-term changes in FEV1 (up to 90 minutes) showed no significant difference between beta2-agonist and ipratropium bromide treated patients. The differences were similar among the studies and when combined: Weighted Mean Difference (WMD) 0.0 liters (95% Confidence Interval (95% CI) -0.19, 0.19). There was no significant additional increase in change in FEV1 on adding ipratropium to beta2-agonist: WMD 0.02 liter (95% CI -0.08, 0.12). Long-term effects (24 hours) of the ipratropium bromide and beta2-agonist treatment combination were similar: WMD 0.05 liters (95%CI -0.14, 0.05). Neither of two studies found significant changes in PaO2, either short- or long-term, with ipratropium vs. beta-agonist, although one showed an increase in PaO2 in subjects receiving ipratropium bromide at 60 minutes. Adverse drug reactions included dry mouth and tremor.

REVIEWER'S CONCLUSIONS

There was no evidence that the degree of bronchodilation achieved with ipratropium bromide was greater than that using a short-acting beta2-agonist. The combination of a beta2-agonist and ipratropium did not appear to increase the effect on FEV1 more than either used alone.

Effects of erythropoietin and aminoguanidine on red blood cell deformability in diabetic azotemic and uremic patients

Impaired red blood cell-deformability (RBC-df) is noted in patients with diabetes and may play a role in the pathogenesis of microvasculopathy and nephropathy. We report the effects of erythropoietin (EPO) alone and combined with aminoguanidine (AG) for 1 year on RBC-df in predialysis patients (P-DPs) with renal insufficiency and in end-stage renal disease (ESRD) patients on maintenance hemodialysis (DPs). Nine P-DPs who received EPO 50 U/kg by subcutaneous injection 3 times per week are compared with 5 P-DPs treated without EPO (mean serum creatinine 4.1 +/- 0.1 versus 4.2 +/- 0.6 mg/dL, respectively). Twelve DPs (Kt/V = 1.5 +/- 0.1) were studied. Six DPs received AG 200 mg/every other day by mouth and EPO 50 U/kg by intravenous (IV) injection, and 6 DPs received EPO (50 U/kg) and placebo and served as control. RBC-df improved significantly in 9 P-DPs treated with EPO at 6 months (from 2.7 +/- 0.1 to 1.6 +/- 0.2, P = 0.005). This positive effect was sustained at 12 months (P = 0.005); there was no change in RBC-df in P-DPs receiving usual care without EPO. RBC-df improved significantly and progressively at 6 and 12 months in DPs treated with EPO and AG (from 2.2 +/- 0.2 to 1.8 +/- 0.2; P = 0.01; 1.2 +/- 0.1; P = 0.001, respectively); there was limited improvement in RBC-df in DPs treated with EPO and placebo. We conclude that EPO treatment significantly improved RBC-df in diabetic P-DPs, but EPO alone has no significant effect on RBC-df after 12 months in diabetic DPs. The combination of EPO and AG restores RBC-df to near-normal levels in diabetic DPs. We speculate that the effect of EPO on RBC-df seen in P-DPs and DPs is related to increased synthesis and influx of new and younger RBCs. AG may confer protection of RBCs in DPs by blocking advanced glycosylated end-product (AGE) formation.

Influence of topsoil tilth and soil moisture status on losses of pesticide to drains from a heavy clay soil

Twelve lysimeters with a surface area of 0.5 m2 and a length of 60 cm were taken over mole drains from a Denchworth heavy clay soil and divided into two groups with either a standard agricultural tilth or a finer topsoil tilth. The influence of topsoil tilth on leaching of the herbicide isoproturon and a bromide tracer was evaluated over a winter season. The effect of variations in soil moisture status in the immediate topsoil on leaching of isoproturon, chlorotoluron and linuron was investigated in the following winter season. Here, water inputs were controlled such that lysimeters received 50 mm at a maximum intensity of 2 mm h-1 over a 4-week period with herbicides applied on day 15. Three treatments received the water either all prior to application, all after application, or evenly spread over the 4-week period. Leaching losses of the three herbicides were monitored for a subsequently drainage event. Analysis of covariance showed a significant effect of topsoil tilth and total flow on both the maximum concentrations (P = 0.034) and total losses (P = 0.012) of isoproturon in drainflow. Both concentrations and losses were c 35% smaller from lysimeters with the finer tilth. However, generation of the fine tilth in the field was restricted by a wet autumn and this is not considered a reliable management option for reducing pesticide losses from heavy clay soils. In the second experiment, variation in soil moisture content prior to and after application did not have any significant effect (P < 0.05) upon subsequent losses of the three herbicides to drains.

Coping with a MEDLIB-L service outage

OBJECTIVE

The study assessed the coping strategies of MEDLIB-L subscribers during an unexpected disruption in the list's service.

METHODS

An online survey of MEDLIB-L subscribers was performed following a six-day service outage in August 1999.

RESULTS

Respondents' information needs resulted in two distinct coping strategies. Subscribers without a recognized information need or an information need determined to be not pressing coped by waiting out the interruption. Subscribers with pressing information needs turned to alternative methods of resolving these needs.

CONCLUSIONS

While most respondents missed the list and the assistance that it provided, many did not feel that the outage required significant coping strategies. The outage was viewed as a "minor stressor" and did not require secondary-level assessment of the availability and suitability of alternative resources.

A physiologically based pharmacokinetic model for ethylene oxide in mouse, rat, and human

Ethylene oxide (EO) is widely used as a gaseous sterilant and industrial intermediate and is a direct-acting mutagen and carcinogen. The objective of these studies was to develop physiologically based pharmacokinetic (PB-PK) models for EO to describe the exposure-tissue dose relationship in rodents and humans. We previously reported results describing in vitro and in vivo kinetics of EO metabolism in male and female F344 rats and B6C3F1 mice. These studies were extended by determining the kinetics of EO metabolism in human liver cytosol and microsomes. The results indicate enzymatically catalyzed GSH conjugation via cytosolic glutathione S-transferase (cGST) and hydrolysis via microsomal epoxide hydrolase (mEH) occur in both rodents and humans. The in vitro kinetic constants were scaled to account for cytosolic (cGST) and microsomal (mEH) protein content and incorporated into PB-PK descriptions for mouse, rat, and human. Flow-limited models adequately predicted blood and tissue EO levels, disposition, and elimination kinetics determined experimentally in rats and mice, with the exception of testis concentrations, which were overestimated. Incorporation of a diffusion-limited description for testis improved the ability of the model to describe testis concentrations. The model accounted for nonlinear increases in blood and tissue concentrations that occur in mice on exposure to EO concentrations greater than 200 ppm. Species differences are predicted in the metabolism and exposure-dose relationship, with a nonlinear relationship observed in the mouse as a result of GSH depletion. These models represent an essential step in developing a mechanistically based EO exposure-dose-response description for estimating human risk from exposure to EO.

Regulation of 15-lipoxygenase isozymes and mucin secretion by cytokines in cultured normal human bronchial epithelial cells

OBJECTIVE AND DESIGN

To study the effects of IL-4, IL-13, IL-1beta, IL-8 and TNFalpha on 15-lipoxygenase(15-LO) isozyme expression and mucin secretion in normal human bronchial epithelial cells.

MATERIAL AND METHODS

The effects of IL-4, IL-13, IL-1beta, IL-8 and TNFalpha on 15-LO isoenzyme mRNA and protein expression, total 15-LO enzyme activity and mucin secretion were examined in cultures of normal human bronchial epithelial cells. In addition, in order to determine whether the observed effects on mucin secretion were due to lipoxygenase (LO) products, the effect of the non-selective LO inhibitor nordihydroguaiaretic acid was examined.

RESULTS

IL-4 and IL- 13 selectively enhanced 15-LOa mRNA and protein levels, and total 15-LO enzyme activity. In contrast, no changes were observed in 15-LOb mRNA or protein levels. IL-4 and IL-13 both reduced mucin secretion in this cell type, however the non-selective LO inhibitor nordihydroguaiaretic acid had no effect on this action of IL-4.

CONCLUSIONS

These data demonstrate that IL-4 and IL-13 selectively regulate the expression of the 15-LOa isozyme. However, 15LOa products do not mediate the IL-4-induced reduction in mucin secretion observed in this cell type.

Evaluation of uncalibrated preferential flow models against data for isoproturon movement to drains through a heavy clay soil

The uncalibrated predictive ability of four preferential flow models (CRACK-NP, MACRO/MACRO_DB, PLM, SWAT) has been evaluated against point rates of drainflow and associated concentrations of isoproturon from a highly structured and heterogeneous clay soil in the south of England. Data were available for four plots for a number of storm events in each of three successive growing seasons. The mechanistic models CRACK-NP and MACRO generally gave reasonable estimates of drainflow over the three seasons, but under-estimated concentrations of isoproturon over a prolonged period in the first season and over-estimated them in the two remaining seasons. CRACK-NP simulated maximum concentrations of isoproturon over the first two events of each of the three seasons of 156, 527 and 24.4 micrograms litre-1, respectively, and matched the observed data (465, 65.1 and 0.65 micrograms litre-1) slightly better than MACRO (69.1, 566 and 58.5 micrograms litre-1). Automatic selection of parameters from soils information within MACRO_DB reduced the emphasis on preferential flow relative to the stand-alone version of MACRO. This gave a poor simulation of isoproturon breakthrough and simulated maximum concentrations were 0, 50.1 and 35.1 micrograms litre-1, respectively. The capacity model PLM gave the best overall simulation of total drainflow for the first two events in each season, but over-estimated concentrations of isoproturon (967, 808 and 51.3 micrograms litre-1). The simple model SWAT represented total drainflow reasonably well and gave the best simulation of maximum isoproturon concentrations (140, 80.2 and 8.2 micrograms litre-1). There was no clear advantage here in using the mechanistic models rather than the simpler models. None of the models tested was able to simulate consistently the data set, and uncalibrated modelling cannot be recommended for such artificially drained heavy clay soils.

Release of PEGylated granulocyte-macrophage colony-stimulating factor from chitosan/glycerol films

We have prepared a new formulation for mucosal delivery of GM-CSF or PEGylated GM-CSF based on a chitosan carrier plus added glycerol to control the rate of release of the protein. Thin dry films comprised of various weight ratios of chitosan to glycerol and containing either granulocyte-macrophage colony-stimulating factor (GM-CSF) or PEGylated GM-CSF, PEG-(GM-CSF), were prepared. The amount of GM-CSF or PEG-(GM-CSF) released from the chitosan/glycerol films was determined using size exclusion high performance liquid chromatography (HPLC-SEC). The amount of PEG-(GM-CSF) released from the films decreased with an increase in the amount of glycerol present in the film. In parallel with this, films with higher glycerol content exhibited a lower degree of equilibrium swelling when immersed in release media. pH measurements of the release media and analysis of the dried films by Fourier-transform infrared spectroscopy (FTIR) suggested that the amount of residual acetic acid in the dry films decreased as the glycerol content increased. This indicates that glycerol may act by displacing and releasing bound acetic acid from the chitosan molecules, resulting in chitosan--glycerol hydrogen bond formation as the film dries. Further, it was found that the release rate and the amount of PEG-(GM-CSF) released decreased with increasing molecular weight of the conjugated PEG. This effect was not observed with films containing physical mixtures of PEG and GM-CSF. The decrease in the fraction of PEG-(GM-CSF) released with increasing PEG molecular weight is believed to be due to the increased steric hindrance of the PEGylated protein molecule during its diffusion out of the swollen chitosan/glycerol film.

Prior exposure to aged and diluted sidestream cigarette smoke impairs bronchiolar injury and repair

The bronchiolar injury/repair response to naphthalene (NA) in mice includes acute distal airway epithelial injury that is followed by epithelial proliferation and redifferentiation, which result in repair of the epithelium within 14 days. To test whether prior exposure to aged and diluted sidestream cigarette smoke (TS) would alter the injury/repair response of the airway epithelium, adult mice were exposed to either filtered air (FA) or smoke for 5 days before injection with either corn oil carrier (CO) or naphthalene. Mice were killed 1 and 14 days after naphthalene injury. Lung and lobar bronchus were examined and measured using high-resolution epoxyresin sections. The control group (FACOFA) that was exposed to filtered air/corn oil/filtered air contained airway epithelium similar to untreated controls at all airway levels. The group exposed to tobacco smoke/corn oil/filtered air (TSCOFA) contained some rounded cells in the small airways and some expansion of the lateral intercellular space in the larger airways. Necrotic or vacuolated cells were not observed. As expected, the epithelium in the group exposed to filtered air/naphthalene/filtered air (FANAFA) contained many light-staining vacuolated Clara cells and squamated ciliated cells within distal bronchioles during the acute injury phase. Repair (including redifferentiation of epithelial cells and restoration of epithelial thickness) was nearly complete 14 days after injury. The extent of Clara cell injury, as assessed in lobar bronchi, was not different between the four groups. Although the FANAFA group contained greater initial injury in the distal airways at 1 day, the group exposed to tobacco smoke/naphthalene/filtered air (TSNAFA) had the least amount of epithelial repair at 14 days after naphthalene treatment; many terminal bronchioles contained abundant squamated undifferentiated epithelium. We conclude that tobacco smoke exposure prior to injury (1) does not change the target site or target cell type of naphthalene injury, since Clara cells in terminal bronchioles are still selectively injured; (2) results in slightly diminished acute injury from naphthalene in distal bronchioles; and (3) delays bronchiolar epithelial repair.

The neprilysin family in health and disease

The mammalian neprilysin (NEP) family comprises at least seven members: NEP itself, Kell blood group antigen (KELL), the endothelin-converting enzymes (ECE-1 and ECE-2), the enzyme PEX, associated with X-linked hypophosphataemia, "X-converting enzyme" (XCE) a CNS-expressed orphan peptidase and a soluble, secreted endopeptidase (SEP). These zinc metallopeptidases are all type II integral membrane proteins. Where identified, these enzymes have roles in the processing or metabolism of regulatory peptides and therefore represent potential therapeutic targets. A distinct feature of ECE-1 species is their existence as distinct isoforms differing in their N-terminal cytoplasmic tails. These tails play a role in enzyme targeting and turnover with di-leucine and tyrosine-based motifs affecting localization. Additional anchorage of these enzymes can also occur through palmitoylation. Bacterial homologues of the neprilysin family exist, for example the products of the pepO genes from L. lactis and S. parasanguis, and a recently described gene product of P. gingivalis which is an ECE-1 homologue that can catalyse the conversion of big endothelin to endothelin. A genomics based approach to understanding the functions of this proteinase family is aided by the completion of the C. elegans and Drosophila genomes, both of which encode multiple copies of NEP-like enzymes.

Body mass index and the prevalence of hypertension and dyslipidemia

OBJECTIVE

To describe and evaluate relationships between body mass index (BMI) and blood pressure, cholesterol, high-density lipoprotein-cholesterol (HDL-C), and hypertension and dyslipidemia.

RESEARCH METHODS AND PROCEDURES

A national survey of adults in the United States that included measurement of height, weight, blood pressure, and lipids (National Health and Nutrition Examination Survey III 1988-1994). Crude age-adjusted, age-specific means and proportions, and multivariate odds ratios that quantify the association between hypertension or dyslipidemia and BMI, controlling for race/ethnicity, education, and smoking habits are presented.

RESULTS

More than one-half of the adult population is overweight (BMI of 25 to 29.9) or obese (BMI of > or =30). The prevalence of high blood pressure and mean levels of systolic and diastolic blood pressure increased as BMI increased at ages younger than 60 years. The prevalence of high blood cholesterol and mean levels of cholesterol were higher at BMI levels over 25 rather than below 25 but did not increase consistently with increasing BMI above 25. Rates of low HDL-C increased and mean levels of HDL-C decreased as levels of BMI increased. The associations of BMI with high blood pressure and abnormal lipids were statistically significant after controlling for age, race or ethnicity, education, and smoking; odds ratios were highest at ages 20 to 39 but most trends were apparent at older ages. Within BMI categories, hypertension was more prevalent and HDL-C levels were higher in black than white or Mexican American men and women.

DISCUSSION

These data quantify the strong associations of BMI with hypertension and abnormal lipids. They are consistent with the national emphasis on prevention and control of overweight and obesity and indicate that blood pressure and cholesterol measurement and control are especially important for overweight and obese people.

Functional significance of the isoforms of endothelin-converting enzyme-1

The subcellular localization of endothelin-converting enzyme-1 (ECE-1) is a matter of some controversy, further complicated by the discovery of its multiple isoforms. ECE-1 is a critical enzyme in the biosynthesis of the potent vasoconstrictor peptide endothelin (ET), and, as such, represents a potential target for drug therapy in the control of disease states involving the ET system. Knowledge of the precise locations of the isoforms and their regulation would aid in the design of drugs to target specifically ECE-1. In this study, the subcellular localization and potential targeting pathways of the ECE-1 isoforms were investigated. Antipeptide antibodies were raised to the unique N-terminal sequence of ECE-1b and were then used in the investigation of its subcellular distribution. Mutagenesis of proposed targeting sequences within the cytoplasmic tails of the isoforms was carried out to determine their significance in subcellular localization.

Pesticides in rainfall in Europe

Papers and published reports investigating the presence of pesticides in rainfall in Europe were reviewed. Approximately half of the compounds that were analysed for were detected. For those detected, most concentrations were below about 100 ng/l, but larger concentrations, up to a few thousand nanograms per litre, were detected occasionally at most monitoring sites. The most frequently detected compounds were lindane (gamma-HCH) and its isomer (alpha-HCH), which were detected on 90-100% of sampling occasions at most of the sites where they were monitored. For compounds developed more recently, detection was usually limited to the spraying season. A classification of pesticides according to their deposition pattern is proposed.

The organic cation transporter OCT2 mediates the uptake of beta-adrenoceptor antagonists across the apical membrane of renal LLC-PK(1) cell monolayers

Previous studies have shown that beta-adrenoceptor antagonists may be substrates of organic cation transporters in kidney and lung. In this study we examined the transport of the beta-adrenoreceptor antagonists propranolol and metoprolol, in renal LLC-PK(1) cell monolayers. Experiments with BCECF (2', 7'-bis(2carboxyethyl)-5(6)-carboxyfluorescein) loaded LLC-PK(1) cell monolayers demonstrated that metoprolol and propranolol flux across the basolateral membrane was consistent with non-ionic diffusion. Flux across the apical membrane consisted of both non-ionic diffusion and the uptake of the cationic form of the beta-adrenoceptor antagonists. Uptake of the cationic form of metoprolol across the apical membrane was Na(+)-independent, electrogenic and sensitive to external pH. Furthermore, uptake was sensitive to inhibition by Decynium-22 and the organic cations TEA (tetraethylammonium) and MPP(+) (1-methyl 4-phenylpyridinium). These results, allied with the apical location of the uptake mechanism suggest that beta-adrenoceptor antagonists may be substrates for the organic cation transporter, OCT2. To confirm beta-adrenoceptor antagonists as substrates for OCT2, we demonstrate, in cells transiently transfected with an epitope tagged version of hOCT2 (hOCT2-V5):(1) Decynium-22 sensitive [(14)C]-propranolol uptake, (2) cis-inhibition of OCT2 by a range of beta-adrenoceptor antagonists and (3) metoprolol induced intracellular acidification.

Characterization of MPP+ secretion across human intestinal Caco-2 cell monolayers: role of P-glycoprotein and a novel Na(+)-dependent organic cation transport mechanism

1. In the kidney, a number of transport proteins involved in the secretion of permanently charged organic cations have recently been cloned. To evaluate the possible similarities between intestine and kidney in the handling of organic cations we investigated the transport of 1-methyl-4-phenylpyridinium (MPP+) across monolayers of intestinal Caco-2 cells. MPP+ is a prototypic substrate of the cloned organic cation transporters hOCT1 and hOCT2. 2. In Caco-2 cell monolayers, the basolateral to apical flux of MPP+ was significantly greater than the apical to basolateral flux, consistent with net secretion of MPP+. 3. Net secretion of MPP+ was abolished by addition of either 10 microM cyclosporin A or 100 microM verapamil to the apical membrane. In contrast, secretion of MPP+ was unaffected by addition of either TEA (2 mM) or decynium-22 (2 microM) to either apical or basolateral membranes. These results suggest that MPP+ secretion is mediated primarily by P-glycoprotein located at the apical membrane. We found no evidence of a role for hOCT1 or hOCT2 in the secretion of MPP+. 4. In addition to net secretion of MPP+, we found evidence of a Na(+)-dependent MPP+ uptake mechanism at the apical membrane of Caco-2 cells. 5. Na(+)-dependent MPP+ uptake was sensitive to inhibition by the organic cations; decynium-22 (2 microM), TEA (2 mM) and cimetidine (5 mM) but not by carnitine, guanidine or proline. 6. These results suggest that net secretion of MPP+ across the apical membrane of Caco-2 cells is a function of the relative contributions of MPP+ secretion mediated by P-glycoprotein and MPP+ absorption mediated by a novel Na(+)-dependent transport mechanism.

Early events in naphthalene-induced acute Clara cell toxicity: comparison of membrane permeability and ultrastructure

Naphthalene causes severe dose- and site-selective injury to mouse nonciliated bronchiolar (Clara) epithelial cells. Toxicity is characterized by exfoliation of injured Clara cells into the airway lumen 24 h after exposure. The purpose of this study was to define the temporal pattern of intracellular changes immediately following naphthalene treatment, with the goal of identifying critical early events involved in cytotoxicity. Mice were injected with naphthalene or carrier and were killed 1, 2, 3, and 6 h after treatment (PT). Loss of membrane integrity was assessed by ethidium homodimer-1 permeability and confocal microscopy. Cell morphology and ultrastructure were evaluated using high-resolution light and electron microscopy. Permeable cells were found only in terminal bronchioles and increased in abundance with time PT. At 2 and 3 h PT, when most Clara cells had early signs of injury, few permeable cells were detected. Many Clara cells had apical membrane blebs that contained abundant, swollen, smooth endoplasmic reticulum (SER) and few other organelles. By 6 h PT many Clara cells were membrane-permeable. However, many permeable Clara cells lacked apical blebs and SER was less abundant in these cells. Cytoplasmic blebbing may be a mechanism to protect the cell by isolating and removing damaged SER. We conclude that the early stages of injury include SER swelling and bleb formation which precede increases in cell membrane permeability after acute naphthalene injury to bronchiolar Clara cells in vivo.

The global topography of Mars and implications for surface evolution

Elevations measured by the Mars Orbiter Laser Altimeter have yielded a high-accuracy global map of the topography of Mars. Dominant features include the low northern hemisphere, the Tharsis province, and the Hellas impact basin. The northern hemisphere depression is primarily a long-wavelength effect that has been shaped by an internal mechanism. The topography of Tharsis consists of two broad rises. Material excavated from Hellas contributes to the high elevation of the southern hemisphere and to the scarp along the hemispheric boundary. The present topography has three major drainage centers, with the northern lowlands being the largest. The two polar cap volumes yield an upper limit of the present surface water inventory of 3.2 to 4.7 million cubic kilometers.

Phosphorylated serine422 on tau proteins is a pathological epitope found in several diseases with neurofibrillary degeneration

Neuronal inclusions with bundles of abnormal filaments made of tau polymers are found in numerous diseases with neurofibrillary degeneration. Tau proteins are the basic components of paired helical filaments (PHF) in Alzheimer's disease (AD), and are abnormally phosphorylated. A disease-specific phosphorylation site at serine422 was demonstrated on PHF, but not on tau proteins from biopsy-derived brain samples. In the present study, we report the characterization of a polyclonal antibody (988) against the serine422 phosphorylation site. By using biochemical and immunohistochemical methods, we confirmed that it is not found on tau proteins from biopsy- or autopsy-derived control samples, and we investigated the presence of this epitope on tau proteins in several neurodegenerative disorders, including AD, Down syndrome (DS), Guamanian amyotrophic lateral sclerosis/Parkinsonism-dementia complex (ALS/PDC), corticobasal degeneration (CBD), progressive supranuclear palsy (PSP), postencephalitic parkinsonism (PEP) and Pick's disease (PiD). By Western blotting, antibody 988 labeled the characteristic tau triplet (tau 55, 64, 69) in AD, DS, Guamanian ALS/PDC and PEP. PSP and CBD exhibited their typical tau doublet (tau 64, 69), whereas the doublet tau 55 and 64 was detected in PiD. In all of these neurodegenerative disorders, antibody 988 clearly labeled NFT and dystrophic neurites, as well as Pick bodies in PiD cases, whereas no staining was observed in control cases. These data indicate that phosphorylation of serine422 on tau proteins is a common feature among neurodegenerative disorders and is therefore not specific of AD. Moreover, phosphorylation of this epitope permits the distinction between normal tau proteins and pathological tau proteins.

Characterization of the analgesic and anti-inflammatory activities of ketorolac and its enantiomers in the rat

The marked analgesic efficacy of ketorolac in humans, relative to other nonsteroidal anti-inflammatory drugs (NSAIDs), has lead to speculation as to whether additional non-NSAID mechanism(s) contribute to its analgesic actions. To evaluate this possibility, we characterized (R,S)-ketorolac's pharmacological properties in vivo and in vitro using the nonselective cyclooxygenase (COX) inhibitors [indomethacin (INDO) and diclofenac sodium (DS)] as well as the selective COX-2 inhibitor, celecoxib, as references. The potency of racemic (R,S)-ketorolac was similar in tests of acetic acid-induced writhing, carrageenan-induced paw hyperalgesia, and carrageenan-induced edema formation in rats; ID50 values = 0.24, 0. 29, and 0.08 mg/kg, respectively. (R,S)-ketorolac's actions were stereospecific, with (S)-ketorolac possessing the biological activity of the racemate in the above tests. The analgesic potencies for (R,S)-, (S)-, and (R)-ketorolac, INDO, and DS were highly correlated with their anti-inflammatory potencies, suggesting a common mechanism. (R,S)-ketorolac was significantly more potent than INDO or DS in vivo. Neither difference in relative potency of COX inhibition for (R,S)-ketorolac over INDO and DS nor activity of (S)-ketorolac at a number of other enzymes, channels, or receptors could account for the differences in observed potency. The distribution coefficient for (R,S)-ketorolac was approximately 30-fold less than for DS or INDO, indicating that (R,S)-ketorolac is much less lipophilic than these NSAIDs. Therefore, the physicochemical and pharmacokinetics properties of (R,S)-ketorolac may optimize the concentrations of (S)-ketorolac at its biological target(s), resulting in greater efficacy and potency in vivo.

Anti-peptide antibodies specific to rat endothelin-converting enzyme-1 isoforms reveal isoform localisation and expression

Endothelin-converting enzyme-1 (ECE-1) is a critical enzyme in the biosynthesis of the potent vasoconstrictor peptide endothelin and exists in several isoforms. Anti-peptide antibodies raised against epitopes in the distinct N-terminal cytoplasmic tails of the rat ECE-1 isoforms have been obtained. By using these antibodies in Western blot analysis and immunofluorescence studies, we have shown that cultures of transformed rat lung vascular endothelial cells treated with the metalloprotease inhibitor phosphoramidon and untreated cells express ECE-1alpha only, whereas human umbilical vein endothelial cells express ECE-1alpha and ECE-1beta. The ECE-1 isoforms expressed in CHO-K1 cells transfected with rat cDNA to ECE-1alpha and ECE-1beta could be immunoprecipitated by using the appropriate isospecific antibody.

Ethylene oxide dosimetry in the mouse

Ethylene oxide (EO) is a direct-acting mutagen and animal carcinogen used as an industrial intermediate and sterilant with a high potential for human exposure. Understanding the exposure-dose relationship for EO in rodents is critical for developing human EO exposure-dose models. The study reported here examined the dosimetry of EO in male B6C3F1 mice by direct determination of blood EO concentrations. Steady-state blood EO concentrations were measured during a single 4-h nose-only inhalation exposure (0, 50, 100, 200, 300, or 400 ppm EO). In addition, glutathione (GSH) concentrations were measured in liver, lung, kidney, and testis to assess the role of the GSH depletion in the saturable metabolism previously observed in mice (Brown et al., Toxicol. Appl. Pharmacol. 136, 8-19, 1996). Blood EO concentrations were found to increase linearly with exposure concentration up to 200 ppm. Markedly sublinear blood dosimetry was observed at exposure concentrations exceeding 200 ppm. An EO exposure concentration-dependent reduction in tissue GSH levels was observed, with both liver and lung GSH levels significantly depressed at EO exposure concentrations of 100 ppm or greater. Our results also indicate that depletion of GSH is likely responsible for nonlinear dosimetry of EO in mice and that GSH depletion corresponds with reports of dose-rate effects in mice exposed to EO.

Surgical margins for excision of primary cutaneous melanoma

BACKGROUND

A major controversy in the treatment of melanoma is the width of the surgical margin necessary for complete excision. Although surgical margins have decreased in recent years, the current recommendations are mainly based on arbitrary choices, only two of which have been tested in clinical trials.

OBJECTIVE

Our purpose was to use prospective data, measuring the extent of subclinical melanoma extensions, to develop guidelines for predetermined surgical margins for the excision of cutaneous melanoma.

METHODS

A prospectively collected series of 535 patients with 553 primary cutaneous melanomas was studied. All melanomas were excised by means of the fresh tissue technique of Mohs micrographic surgery with frozen section examination of the margin. The surgical margin needed for excision of melanoma was determined by measuring the invisible extensions of tumor around the melanoma. The minimum surgical margin was 6 mm and the total margin was calculated by adding an additional 3 mm for any melanoma requiring a subsequent stage to remove the tumor completely.

RESULTS

Eighty-three percent of melanomas were successfully excised with a 6 mm margin; 9 mm removed 95% of the melanomas; and a 1.2 cm margin was necessary to remove 97% of all melanomas. Margins to remove melanomas on the head, neck, hands, and feet were wider than those on the trunk and extremities. Margins to remove melanomas that were more than 2 to 3 cm in diameter were wider than for smaller melanomas.

CONCLUSION

Predetermined surgical margins for excision of melanoma or melanoma in situ by standard surgical techniques should include 1 cm of normal-appearing skin for melanomas on the trunk and proximal extremities that are smaller than 2 cm in diameter, or a 1.5 cm margin for tumors larger than 2 cm in diameter. For melanomas on the head, neck, hands, and feet, a minimum surgical margin of 1.5 cm is recommended or a margin of 2.5 cm for melanomas larger than 3 cm in diameter. Mohs micrographic surgery is a useful alternative to standard surgery when more narrow margins are desired, particularly for melanomas on the head, neck, hands, and feet, or melanomas larger than 2.5 cm in diameter, or for melanomas without distinct clinical margins.

Cardiovascular health risks related to overweight

Cross-sectional surveys of the civilian noninstitutionalized population of the United States, including in-home interviews and clinical examinations, were employed to examine trends in consumption of energy and fat, prevalence of overweight in the population, the association of overweight with levels of blood pressure and blood cholesterol, and the prevalence of high blood pressure and high blood cholesterol among the overweight compared with the nonoverweight. Data from participants 20 years of age and older are reported. Study results suggest that total mean energy intake, although generally accepted to be underreported in dietary surveys, may have increased. Total fat and saturated fat intake as a percent of energy decreased, but remained above recommended levels. Overweight has increased in the population, despite decreases in the prevalence of high blood pressure and high blood cholesterol levels. Increased levels of overweight, reported as body mass index, are associated with increased cardiovascular risk factors of high blood pressure and high blood cholesterol. These data suggest the need for health care practitioners to emphasize the requirement for energy balance (or weight loss if overweight, ie, not at a "healthy weight"). A focus on fat intake alone without emphasis on energy balance is inadequate for achieving and maintaining recommended weight.

Osteochondritis dissecans of the patella: arthroscopic fixation with bioabsorbable pins

Osteochondritis dissecans of the patella is a relatively rare condition. Surgical treatment has been recommended for those patients who fail conservative treatment, or who present with mechanical symptoms or loose bodies. In an attempt to preserve the patellofemoral articulation, we describe a new technique to arthroscopically fix osteochondritic lesions of the patella using bioabsorbable pins. This technique avoids the morbidity of a formal arthrotomy as well as the complications associated with metallic hardware.

Metabolism and testicular toxicity of 1,3-dinitrobenzene in the rat: evaluation of the stage-synchrony model

Because many testicular toxicants cause damage to specific stages of spermatogenesis, the present study has investigated the utility of a model in which the testis is synchronized to contain only a few closely related spermatogenic stages. The susceptibility of different stages to 1,3-dinitrobenzene (1,3-DNB) toxicity was investigated in rats, the testes of which had been stage synchronized by a vitamin A depletion/repletion (VADR) procedure. 1,3-DNB (25 mg/kg, IP) or vehicle was injected 58, 61, or 78 d after vitamin A readministration, and testicular histopathology was evaluated 48 h later. At the time of sacrifice, testes in the three groups were synchronized to stages I-VI, VII-IX, or X-XIV+I. The data indicated that tubules in all stages of spermatogenesis, in both synchronized and unsynchronized animals, demonstrated histopathologic changes in response to 1,3-DNB. However, the lesion seen in synchronized animals was more severe and less stage specific than that seen in weight-matched, unsynchronized animals. This increase in degree of susceptibility could be partially explained by differences in toxicokinetics. Stage-synchronized testes could provide unique insights into stage-specific cellular and molecular events, especially for in vitro studies where the stage enrichment could be maximally exploited. However, results obtained from in vivo toxicity studies using animals subjected to VADR should be interpreted carefully in light of the confounding physiologic/metabolic perturbations potentially induced by the VADR procedure.

Chloride channel blockers decrease intracellular pH in cultured renal epithelial LLC-PK1 cells

The effects of chloride channel blockers upon intracellular pH (pHi) were examined in renal epithelial monolayers of LLC-PK1 cells. A significant intracellular acidification was found with addition of 100 microM 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB), niflumic acid, flufenamate and diphenylamine-2-carboxylate (DPC) but not with 4,4'-diisothiocyanatostilbene-2-2'disulphonic acid (DIDS). The effects of these agents upon pHi was dose-dependent with apparent K0.5 values of: 16.7 +/- 0.3 microM, 34.2 +/- 0.9 microM and 740 +/- 13 microM for niflumic acid, flufenamate and DPC respectively. The results indicate that at concentrations commonly used to block channel activity these chloride channel blockers have profound effects upon pHi.

Mediation of cimetidine secretion by P-glycoprotein and a novel H(+)-coupled mechanism in cultured renal epithelial monolayers of LLC-PK1 cells

1. Previous studies have shown that the weak base, cimetidine, is actively secreted by the renal proximal tubule. In this study we have examined the transport of cimetidine by renal LLC-PK1 epithelial cell monolayers. 2. In LLC-PK1 cell monolayers the basal-to-apical flux of cimetidine was significantly greater than the apical-to basal flux, consistent with net secretion of cimetidine in a basal-to-apical direction. 3. Net secretion of cimetidine was significantly (70%) reduced by the addition of either 100 microM verapamil or 100 microM nifedipine to the apical membrane. The reduction in net secretion was the result of an inhibition of basal-to-apical flux; these agents had no effect upon flux in the apical-to-basal direction. These results suggest that cimetidine secretion is mediated primarily by P-glycoprotein located in the apical membrane. In addition we found no evidence of a role for organic cation antiport in the secretion of cimetidine. 4. In the presence of an inwardly directed proton gradient across the apical membrane (pH 6.0), cimetidine secretion was significantly reduced compared to that measured at an apical pH of 7.4. The reduction in net secretion at pH 6.0 was the result of a stimulation of cimetidine uptake across the apical membrane. This pH-dependent uptake mechanism was sensitive to inhibition by DIDS (100 microM). 5. Experiments with BCECF (2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein) loaded monolayers demonstrated that cimetidine influx across the apical membrane was associated with proton flow into the cell and was sensitive to inhibition by DIDS. 6. These results suggest that net secretion of cimetidine across the apical membrane is a function of the relative magnitudes of cimetidine secretion mediated by P-glycoprotein and cimetidine absorption mediated by a novel proton-coupled, DIDS-sensitive transport mechanism.

In vivo and in vitro kinetics of ethylene oxide metabolism in rats and mice

Ethylene oxide (EO) is a direct-acting mutagen and animal carcinogen used as an industrial intermediate and sterilant with a high potential for human exposure. Kinetics of EO metabolism in rodents can be used to develop human EO dosimetry models. This study examined the kinetics of EO metabolism in vivo and in vitro in male and female F-344 rats and B6C3F1 mice. In vivo studies measured blood and tissue EO levels during and 2-20 min following whole-body inhalation exposure (4 hr, 100 or 330 ppm EO). At 100 ppm EO, the half-life of elimination (t1/2) in rats was 13.8 +/- 0.3 (mean +/- SD) and 10.8 +/- 2.4 min for males and females, respectively, compared to a t1/2 in mice of 3.12 +/- 0.2 and 2.4 +/- 0.2 min in males and females, respectively. On exposure to 330 ppm EO, the t1/2 in mice increased approx twofold, while no change in t1/2 was observed in rats. In vitro kinetic parameters (Vmax and KM) of EO metabolism were determined using tissue cytosol and microsomes. EO metabolism in vitro occurred primarily via cytosolic glutathione S-transferase-mediated EO-GSH conjugation (cGST-EO), with highest activity in the liver. Liver cGST-EO activity (Vmax) was 258 +/- 86.9 and 287 +/- 49.0 nmol/mg protein/min (mean +/- SD) in male and female mice, respectively, compared to 52.7 +/- 10.8 and 29.3 +/- 4.9 in male and female rats, respectively. In rats, but not mice, there was a statistically significant (p < 0.05) gender difference in the Vmax for liver cGST. The KM for liver cGST-EO was approximately 10 mM in both species. The higher Vmax values observed in mice are consistent with the more rapid elimination of EO observed for this species in vivo compared to rats.

Metabolism and testicular toxicity of 1,3-dinitrobenzene in the rat: effect of route of administration

Studies investigating the testicular toxicity of 1,3-dinitrobenzene (1,3-DNB) have utilized both the oral (po) and intraperitoneal (ip) routes of administration. These two administration routes could be expected to produce different pharmacokinetic profiles and, potentially, different degrees of toxicity. In the present work, the effect of route of administration upon 1,3-DNB disposition and susceptibility to testicular damage has been investigated. Male Sprague-Dawley rats were given 25 mg/kg 1,3-DNB either ip or po. Metabolites were quantitated in blood, urine, and feces, and methemoglobin levels were determined. Peak blood levels of 1,3-DNB and its major metabolite were three times higher in ip-dosed rats than in po-dosed rats. While the lower blood levels seen after po administration were maintained for greater than 6 hr, blood levels fell rapidly after ip dosing, reaching po levels at 6 hr postadministration. Peak methemoglobin levels in ip-dosed animals were twice that of po-dosed animals. Route of administration had a minor effect on the levels of urinary metabolites, while there was a significantly higher excretion of metabolites in the feces of po-dosed animals. Despite the markedly higher 1,3-DNB blood levels after ip administration, there were only subtle differences in testicular damage. The data raise the possibility that above a threshold level of 1,3-DNB in the blood, only the duration of testicular exposure to the toxicant may govern susceptibility to testicular toxicity.