Asthma - is survival good enough?

Advances in asthma management, particularly the introduction of controller medication of which inhaled corticosteroids are the most important, has resulted in a steady decline in asthma mortality in most countries. This is usually accompanied by a decline in episodes of near-fatal asthma attacks and hospitalisations, and a reduction in other indicators of asthma morbidity. These gains have led to a shift in thinking on the management of asthma, away from simply preventing death and hospitalisations, toward achieving and maintaining sustained control of all clinical features

Seasonal abundance of small cladocerans in Lake Mangakaware, Waikato, New Zealand

The seasonal changes in the dynamics and life histories of the Cladocera in Lake Mangakaware, North Island, New Zealand, were studied over 19 months by sampling at weekly or 2-weekly intervals. Lake Mangakaware is a 13.3 ha polymictic lake with high nutrient status, low Secchi disc transparencies, and an unstable thermal regime. The four planktonic cladoceran species (Bosmina longirostris, B. meridionalis, Ceriodaphnia pulchella, and C. dubia) exhibited disjunct population maxima. Only B. longirostris was perennially present. All species exhibited low fecundities and low lipid content, indicating that food resources were limited and that competitive interactions and resistance to starvation were probably important in determining species success. Increases in body size in cooler seasons were unrelated to clutch size, giving further support for the view that available food was limited. These results are consistent with previous experimental findings that subtle differences in life history can determine seasonal success and the outcome of competition between similar species

Adherence to isoniazid prophylaxis among HIV-infected children: a randomized controlled trial comparing two dosing schedules

<p>Abstract</p> <p>Background</p> <p>Tuberculosis contributes significantly to morbidity and mortality among HIV-infected children in sub-Saharan Africa. Isoniazid prophylaxis can reduce tuberculosis incidence in this population. However, for the treatment to be effective, adherence to the medication must be optimized. We investigated adherence to isoniazid prophylaxis administered daily, compared to three times a week, and predictors of adherence amongst HIV-infected children.</p> <p>Methods</p> <p>We investigated adherence to study medication in a two centre, randomized trial comparing daily to three times a week dosing of isoniazid. The study was conducted at two tertiary paediatric care centres in Cape Town, South Africa. Over a 5 year period, we followed 324 HIV-infected children aged ≥ 8 weeks. Adherence information based on pill counts was available for 276 children. Percentage adherence was calculated by counting the number of pills returned. Adherence ≥ 90% was considered to be optimal. Analysis was done using summary and repeated measures, comparing adherence to the two dosing schedules. Mean percentage adherence (per child during follow-up time) was used to compare the mean of each group as well as the proportion of children achieving an adherence of ≥ 90% in each group. For repeated measures, percentage adherence (per child per visit) was dichotomized at 90%. A logistic regression model with generalized estimating equations, to account for within-individual correlation, was used to evaluate the impact of the dosing schedule. Adjustments were made for potential confounders and we assessed potential baseline and time-varying adherence determinants.</p> <p>Results</p> <p>The overall adherence to isoniazid was excellent, with a mean adherence of 94.7% (95% confidence interval [CI] 93.5-95.9); similar mean adherence was achieved by the group taking daily medication (93.8%; 95% CI 92.1-95.6) and by the three times a week group (95.5%; 95% CI 93.8-97.2). Two-hundred and seventeen (78.6%) children achieved a mean adherence of ≥ 90%. Adherence was similar for daily and three times a week dosing schedules in univariate (odds ratio [OR] 0.88; 95% CI 0.66-1.17; <it>P </it>= 0.38) and multivariate (adjusted OR 0.85; 95% CI 0.64-1.11; <it>P </it>= 0.23) models. Children from overcrowded homes were less adherent (adjusted OR 0.71; 95% CI 0.54-0.95; <it>P </it>= 0.02). Age at study visit was predictive of adherence, with better adherence achieved in children older than 4 years (adjusted OR 1.96; 95% CI 1.16-3.32; <it>P </it>= 0.01).</p> <p>Conclusion</p> <p>Adherence to isoniazid was excellent regardless of the dosing schedule used. Intermittent dosing of isoniazid prophylaxis can be considered as an alternative to daily dosing, without compromising adherence or efficacy.</p> <p>Trial registration</p> <p>Clinical Trials NCT00330304</p

Sperm Quality of Hatchery-Reared Lake Trout Throughout the Spawning Season

The objective of this study was to investigate variation in sperm quality metrics (motility, velocity, linearity, longevity, and density) of hatchery-reared Lake Trout Salvelinus namaycush throughout the spawning season. Seasonal variation in sperm quality was investigated using both a regression and repeated-measures approach. Sperm was collected from the same 16 individuals over four sampling periods, separated by 3-week intervals. Regression analyses showed that 727% of the variation in sperm traits could be explained by seasonal variation, indicating that seasonality can have a significant impact on the quality of sperm. Significant positive linear relationships were found for percent motility and linearity at 5s postactivation. Significant negative quadratic relationships were found for velocity at 5s postactivation, longevity, and density, whereas a positive quadratic relationship was found for linearity at 10s postactivation. Repeated measures ANOVAs showed a significant effect of season for percent motility and linearity at 5 and 10s postactivation, velocity at 10s postactivation, and longevity. Our findings are important for optimizing fertilization protocols for hatchery production and can also be used to understand reproductive biology and ecology of wild Lake Trout stocks. Received March 15, 2012; accepted June 30, 201

Microplastic in Surface Waters of Urban Rivers: Concentration, Sources, and Associated Bacterial Assemblages

The ecological dynamics of microplastic (\u3c5 mm) are well documented in marine ecosystems, but the sources, abundance, and ecological role of microplastic in rivers are unknown and likely to be substantial. Microplastic fibers (e.g., synthetic fabrics) and pellets (e.g., abrasives in personal care products) are abundant in wastewater treatment plant (WWTP) effluent, and can serve as a point source of microplastic in rivers. The buoyancy, hydrophobic surface, and long transport distance of microplastic make it a novel substrate for the selection and dispersal of unique microbial assemblages. We measured microplastic concentration and bacterial assemblage composition on microplastic and natural surfaces upstream and downstream of WWTP effluent sites at nine rivers in Illinois, United States. Microplastic concentration was higher downstream of WWTP effluent outfall sites in all but two rivers. Pellets, fibers, and fragments were the dominant microplastic types, and polymers were identified as polypropylene, polyethylene, and polystyrene. Mean microplastic flux was 1,338,757 pieces per day, although the flux was highly variable among nine sites (min = 15,520 per day, max = 4,721,709 per day). High-throughput sequencing of 16S rRNA genes showed bacterial assemblage composition was significantly different among microplastic, seston, and water column substrates. Microplastic bacterial assemblages had lower taxon richness, diversity, and evenness than those on other substrates, and microplastic selected for taxa that may degrade plastic polymers (e.g., Pseudomonas) and those representing common human intestinal pathogens (e.g., Arcobacter). Effluent from WWTPs in rivers is an important component of the global plastic “life cycle,” and microplastic serves as a novel substrate that selects and transports distinct bacterial assemblages in urban rivers. Rates of microplastic deposition, consumption by stream biota, and the metabolic capacity of microplastic biofilms in rivers are unknown and merit further research

Does Seasonal Reproductive State Affect the Neuroendocrine Response of the Ewe to a Long-Day Pattern of Melatonin?

This study examined whether or not the reproductive response of female sheep to photoperiod varies with seasonal reproductive state. The specific objective was to test the hypothesis that the reproductive response to a long-day pattern of melatonin varies with the reproductive state of the ewe. The response examined was the synchronization of reproductive neuroendocrine induction (rise in serum luteinizing hormone, or LH) following nocturnal infusion of melatonin into pinealectomized ewes for 35 consecutive nights. This infusion restored a pattern of circulating melatonin similar to that in pineal-intact ewes maintained in a long photoperiod (LD 16:8). The ewes had been pinealectomized and without melatonin replacement for 16-25 months prior to the study. They were in differing reproductive states at the start of the infusion, as their endogenous reproductive rhythm had become desynchronized among individuals and with respect to time of year. Noninfused pinealectomized ewes served as controls. Regardless of the reproductive state at the start of the 35-day infusion of the long-day pattern of melatonin, all treated ewes exhibited the same reproductive neuroendocrine response after the infusion was ended. This consisted of a synchronized rise in LH some 6-8 weeks after the infusion was terminated, the maintenance of a high level of serum LH for some 15 weeks, and a subsequent precipitous fall in LH to a very low level. These results provide evidence that a long-day pattern of melatonin can synchronize reproductive neuroendocrine induction in the ewe, regardless of reproductive condition, and thus do not support the hypothesis that this response differs with seasonal reproductive state.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66625/2/10.1177_074873049200700101.pd

A Comparative Study between Two Regression Methods on LiDAR Data: A Case Study

Airborne LiDAR (Light Detection and Ranging) has become an excellent tool for accurately assessing vegetation characteristics in forest environments. Previous studies showed empirical relationships between LiDAR and field-measured biophysical variables. Multiple linear regression (MLR) with stepwise feature selection is the most common method for building estimation models. Although this technique has provided very interesting results, many other data mining techniques may be applied. The overall goal of this study is to compare different methodologies for assessing biomass fractions at stand level using airborne Li- DAR data in forest settings. In order to choose the best methodology, a comparison between two different feature selection techniques (stepwise selection vs. genetic-based selection) is presented. In addition, classical MLR is also compared with regression trees (M5P). The results when each methodology is applied to estimate stand biomass fractions from an area of northern Spain show that genetically-selected M5P obtains the best results

Statistical Methods for Detecting Ichthyoplankton Density Patterns that Influence Entrainment Mortality

Samples of drifting American shad eggs were collected at two transects in the Savannah River near industrial water intakes. At each transect the river was divided into four sectors that were sampled at two hour intervals over a 24 hour period. The actual risk of entrainment was approximately 35-50% lower that if the shad eggs were uniformly distributed, and the risk of entrainment was lower at one intake than the other

Melarsoprol cyclodextrin inclusion complexes as promising oral candidates for the treatment of human African trypanosomiasis

Human African trypanosomiasis (HAT), or sleeping sickness, results from infection with the protozoan parasites &lt;i&gt;Trypanosoma brucei&lt;/i&gt; (&lt;i&gt;T.b.&lt;/i&gt;) &lt;i&gt;gambiense&lt;/i&gt; or &lt;i&gt;T.b.rhodesiense&lt;/i&gt; and is invariably fatal if untreated. There are 60 million people at risk from the disease throughout sub-Saharan Africa. The infection progresses from the haemolymphatic stage where parasites invade the blood, lymphatics and peripheral organs, to the late encephalitic stage where they enter the central nervous system (CNS) to cause serious neurological disease. The trivalent arsenical drug melarsoprol (Arsobal) is the only currently available treatment for CNS-stage &lt;i&gt;T.b.rhodesiense&lt;/i&gt; infection. However, it must be administered intravenously due to the presence of propylene glycol solvent and is associated with numerous adverse reactions. A severe post-treatment reactive encephalopathy occurs in about 10% of treated patients, half of whom die. Thus melarsoprol kills 5% of all patients receiving it. Cyclodextrins have been used to improve the solubility and reduce the toxicity of a wide variety of drugs. We therefore investigated two melarsoprol cyclodextrin inclusion complexes; melarsoprol hydroxypropyl-&#846;-cyclodextrin and melarsoprol randomly-methylated-&#946;-cyclodextrin. We found that these compounds retain trypanocidal properties &lt;i&gt;in vitro&lt;/i&gt; and cure CNS-stage murine infections when delivered orally, once per day for 7-days, at a dosage of 0.05 mmol/kg. No overt signs of toxicity were detected. Parasite load within the brain was rapidly reduced following treatment onset and magnetic resonance imaging showed restoration of normal blood-brain barrier integrity on completion of chemotherapy. These findings strongly suggest that complexed melarsoprol could be employed as an oral treatment for CNS-stage HAT, delivering considerable improvements over current parenteral chemotherapy