An Estimate of Avian Mortality at Communication Towers in the United States and Canada

Avian mortality at communication towers in the continental United States and Canada is an issue of pressing conservation concern. Previous estimates of this mortality have been based on limited data and have not included Canada. We compiled a database of communication towers in the continental United States and Canada and estimated avian mortality by tower with a regression relating avian mortality to tower height. This equation was derived from 38 tower studies for which mortality data were available and corrected for sampling effort, search efficiency, and scavenging where appropriate. Although most studies document mortality at guyed towers with steady-burning lights, we accounted for lower mortality at towers without guy wires or steady-burning lights by adjusting estimates based on published studies. The resulting estimate of mortality at towers is 6.8 million birds per year in the United States and Canada. Bootstrapped subsampling indicated that the regression was robust to the choice of studies included and a comparison of multiple regression models showed that incorporating sampling, scavenging, and search efficiency adjustments improved model fit. Estimating total avian mortality is only a first step in developing an assessment of the biological significance of mortality at communication towers for individual species or groups of species. Nevertheless, our estimate can be used to evaluate this source of mortality, develop subsequent per-species mortality estimates, and motivate policy action

Incidence of neurological complications in patients with native-valve infective endocarditis and cerebral microembolism: an open cohort study

The objective of this open cohort study was to assess the association between neurological complications in patients with definite native-valve infective endocarditis (IE) and cerebral microembolism (MES). MES detection was performed with 1-h, bilateral middle cerebral arteries (MCA) insonation using a transcranial Doppler ultrasound (TCD) machine. Thirty patients with definite native-valve IE were stratified into 2 groups based upon the presence of MES. The most striking difference between the 2 groups of patients was the incidence of clinically evident neurological complications. Neurological complications of IE occurred in 10 (83.3%) patients with positive MES and in 6 (33.3%) MES-negative patients (p=0.021). Ischaemic stroke was the most common complication, occurring in 11 of 16 patients, followed by meningitis in 4 patients and cerebritis in 1 patient. There was a trend towards greater in-hospital mortality in patients with recorded MES than in the MES-negative, although this was not statistically significant (33.3% vs 16.6%; p=0.392). Our results reveal a significant association between MES and neurological complications in patients with native-valve IE. TCD is a promising tool in predicting individual patient risk for neurological complications of IE

Identification of inhibitors that dually target the new permeability pathway and dihydroorotate dehydrogenase in the blood stage of Plasmodium falciparum

Plasmodium parasites are responsible for the devastating disease malaria that affects hundreds of millions of people each year. Blood stage parasites establish new permeability pathways (NPPs) in infected red blood cell membranes to facilitate the uptake of nutrients and removal of parasite waste products. Pharmacological inhibition of the NPPs is expected to lead to nutrient starvation and accumulation of toxic metabolites resulting in parasite death. Here, we have screened a curated library of antimalarial compounds, the MMV Malaria Box, identifying two compounds that inhibit NPP function. Unexpectedly, metabolic profiling suggested that both compounds also inhibit dihydroorotate dehydrogense (DHODH), which is required for pyrimidine synthesis and is a validated drug target in its own right. Expression of yeast DHODH, which bypasses the need for the parasite DHODH, increased parasite resistance to these compounds. These studies identify two potential candidates for therapeutic development that simultaneously target two essential pathways in Plasmodium, NPP and DHODH