Treatment of Buruli Ulcer

BU has long been treated by surgical resection. During the last two decades, it has become increasingly clear that antimicrobial treatment, first, using a combination of streptomycin 15 mg/kg i.m. and rifampin 10 mg/kg p.o. for 8 weeks, results in relapse-free cure in lesions &lt;10 cm cross-sectional diameter. Recently, a large clinical trial from Ghana and Benin showed that fully oral treatment—rifampin 10 mg/kg combined with clarithromycin—extended release, 15 mg/kg, also for 8 weeks, was equally effective but less toxic; none of the close to 300 study participants needed surgical resection, and only four had split skin grafts; sequelae were negligible. The use of other antimicrobials including fluoroquinolones has been shown to be effective in cohort studies from Australia. The role of resection surgery was studied in Benin in patients with larger lesions. Compared to patients that were operated on at week 8, a delayed decision on surgery at week 14 appeared beneficial; delay resulted in significantly less patients being operated, with reduced in-hospital treatment, and no difference in healing rate or sequelae. Sequelae such as contractures due to scar formation around joints may need specialized care in dedicated centers. General medical care with adequate nutrition and proper wound care are critical; wound saline rinsing and cleaning, dressings with non-adhesive cover, and absorptive material with short-stretch compression are all important for speedy healing. Other topical treatments (nitric oxide crème; traditional herbal remedies; clay; phenytoin) have been little studied; heat treatment might be an option for those that cannot tolerate antimicrobial treatment, such as during pregnancy. Active, early case finding has been shown to be highly efficacious.</p

Continental-Scale Partitioning of Fire Emissions During the 1997 to 2001 El Niño/La Niña Period

During the 1997 to 1998 El Niño, drought conditions triggered widespread increases in fire activity, releasing CH_4 and CO_2 to the atmosphere. We evaluated the contribution of fires from different continents to variability in these greenhouse gases from 1997 to 2001, using satellite-based estimates of fire activity, biogeochemical modeling, and an inverse analysis of atmospheric CO anomalies. During the 1997 to 1998 El Niño, the fire emissions anomaly was 2.1 ± 0.8 petagrams of carbon, or 66 ± 24% of the CO_2 growth rate anomaly. The main contributors were Southeast Asia (60%), Central and South America (30%), and boreal regions of Eurasia and North America (10%)

Pharmacologic management of Mycobacterium ulcerans infection

Introduction: Pharmacological treatment of Buruli ulcer (Mycobacterium ulcerans infection; BU) is highly effective, as shown in two randomized trials in Africa. Areas covered: We review BU drug treatment–in vitro, in vivo and clinical trials (PubMed: ‘(Buruli OR (Mycobacterium AND ulcerans)) AND (treatment OR therapy).’ We also highlight the pathogenesis of M. ulcerans infection that is dominated by mycolactone, a secreted exotoxin, that causes skin and soft tissue necrosis, and impaired immune response and tissue repair. Healing is slow, due to the delayed wash-out of mycolactone. An array of repurposed tuberculosis and leprosy drugs appears effective in vitro and in animal models. In clinical trials and observational studies, only rifamycins (notably, rifampicin), macrolides (notably, clarithromycin), aminoglycosides (notably, streptomycin) and fluoroquinolones (notably, moxifloxacin, and ciprofloxacin) have been tested. Expert opinion: A combination of rifampicin and clarithromycin is highly effective but lesions still take a long time to heal. Novel drugs like telacebec have the potential to reduce treatment duration but this drug may remain unaffordable in low-resourced settings. Research should address ulcer treatment in general; essays to measure mycolactone over time hold promise to use as a readout for studies to compare drug treatment schedules for larger lesions of Buruli ulcer

Fire-Related Carbon Emissions from Land Use Transitions in Southern Amazonia

Various land-use transitions in the tropics contribute to atmospheric carbon emissions, including forest conversion for small-scale farming, cattle ranching, and production of commodities such as soya and palm oil. These transitions involve fire as an effective and inexpensive means for clearing. We applied the DECAF (DEforestation CArbon Fluxes) model to Mato Grosso, Brazil to estimate fire emissions from various land-use transitions during 2001-2005. Fires associated with deforestation contributed 67 Tg C/yr (17 and 50 Tg C/yr from conversion to cropland and pasture, respectively), while conversion of savannas and existing cattle pasture to cropland contributed 17 Tg C/yr and pasture maintenance fires 6 Tg C/yr. Large clearings (>100 ha/yr) contributed 67% of emissions but comprised only 10% of deforestation events. From a policy perspective, results imply that intensification of agricultural production on already-cleared land and policies to discourage large clearings would reduce the major sources of emissions from fires in this region. Copyright 2008 by the American Geophysical Union

Top-down estimates of global CO sources using MOPITT measurements

We present a synthesis inversion of CO emissions from various geographical regions and for various source categories for the year 2000 using CO retrievals from the MOPITT (Measurements of Pollution in the Troposphere) instrument. We find a large discrepancy between our top‐down estimates and recent bottom‐up estimates of CO emissions from fossil fuel/biofuel (FFBF) use in Asia. A key conclusion of this study is that CO emissions in East Asia (EAS) are about a factor of 1.8–2 higher than recent bottom‐up estimates

In Vitro Susceptibility of Mycobacterium tuberculosis to Amikacin, Kanamycin, and Capreomycin

Amikacin, kanamycin and capreomycin are listed among the most important 2nd line drugs for multidrug resistant tuberculosis. Although amikacin and kanamycin are administered in the same dose and show the same pharmacokinetics, they have different WHO breakpoints suggesting that the two drugs have a different minimal inhibitory concentrations (MIC). The aim of this paper was to investigate possible differences in MIC between the aminoglycosides and capreomycin.Using the direct concentration method, a concentration range of amikacin, kanamycin and capreomycin (0.25, 0.50, 1.0, 2.0, 4.0, 8.0, 16.0, 32.0 and 64.0 mg/L) was tested against 57 clinical Mycobacterium tuberculosis strains. The 7H10 agar plates were examined for mycobacterial growth after 14 days.At 2 mg/L, 48 strains (84%) were inhibited by amikacin and only five strains (9%) were inhibited by kanamycin (p < 0.05, Wilcoxon Signed Rank Test). The median MICs of amikacin, kanamycin and capreomycin were 2, 4 and 8 mg/L, respectively. No difference was observed between multidrug resistant and fully susceptible strains in the MIC-distribution of amikacin, kanamycin and capreomycin.The results indicate that amikacin is more active against M. tuberculosis than kanamycin and capreomycin in the absolute concentration method. The impact of this difference on clinical outcome in daily practice requires a prospective study including pharmacokinetic and pharmacodynamics evaluations