Atmospheric Black Carbon Loadings and Sources over Eastern Sub-Saharan Africa Are Governed by the Regional Savanna Fires.

Vast black carbon (BC) emissions from sub-Saharan Africa are perceived to warm the regional climate, impact rainfall patterns, and impair human respiratory health. However, the magnitudes of these perturbations are ill-constrained, largely due to limited ground-based observations and uncertainties in emissions from different sources. This paper reports multiyear concentrations of BC and other key PM2.5 aerosol constituents from the Rwanda Climate Observatory, serving as a regional receptor site. We find a strong seasonal cycle for all investigated chemical species, where the maxima coincide with large-scale upwind savanna fires. BC concentrations show notable interannual variability, with no clear long-term trend. The Δ14C and δ13C signatures of BC unambiguously show highly elevated biomass burning contributions, up to 93 ± 3%, with a clear and strong savanna burning imprint. We further observe a near-equal contribution from C3 and C4 plants, irrespective of air mass source region or season. In addition, the study provides improved relative emission factors of key aerosol components, organic carbon (OC), K+, and NO3-, in savanna-fires-influenced background atmosphere. Altogether, we report quantitative source constraints on Eastern Africa BC emissions, with implications for parameterization of satellite fire and bottom-up emission inventories as well as regional climate and chemical transport modeling.

A Case Report of Baclofen Toxicity in a Pediatric Patient With Normal Kidney Function Successfully Treated With Hemodialysis.

RATIONALE: Baclofen is a commonly prescribed medication used to decrease spasticity in children with cerebral palsy. Despite its widespread use, this medication has not demonstrated to be consistently effective in clinical studies. Baclofen is also associated with systemic adverse effects due to potent neuronal depression. The management of baclofen toxicity is mainly supportive; however, some studies have shown that hemodialysis may alleviate the symptoms of an overdose and shorten the recovery time. PRESENTING CONCERNS: In this case report, a 6-year-old boy with mild cerebral palsy, neuromyelitis optica, and normal kidney function was found unresponsive at home, with altered mental status, after ingesting 1300 mg of baclofen unobserved. The patient was intubated and mechanically ventilated because of significant neurologic depression with subsequent respiratory failure. DIAGNOSIS: The patient was diagnosed with baclofen-induced encephalopathy. An elevated serum baclofen level of 4.00 µg/mL (therapeutic range of 0.08-0.40 µg/mL) was observed 10 hours after he was found unresponsive. The patient's respiratory status deteriorated; he had high ventilatory requirements and remained comatose. INTERVENTION: With the worsening of his clinical condition in the intensive care unit, hemodialysis, administered via a high-efficiency high-flux dialyzer, was initiated approximately 18 hours after he was found unresponsive. The patient underwent 2 hemodialysis runs spaced 9 hours apart, with blood flow rates approaching 250 mL/min. OUTCOMES: Within 3 hours of the first hemodialysis treatment, the patient started to regain consciousness. He was extubated to room air 6 hours after the second hemodialysis treatment. NOVEL FINDINGS: Supportive management is the primary treatment of baclofen toxicity in a pediatric patient with normal kidney function. Hemodialysis may be considered in severe cases of baclofen toxicity and worsening clinical status, but further studies are needed to confirm this finding.

JUSTIFICATION: Le baclofène est un médicament couramment prescrit pour réduire la spasticité chez les enfants atteints de paralysie cérébrale. Malgré son usage répandu, l'efficacité du baclofène n'a pas été démontrée de façon constante dans les études cliniques. Ce médicament est également associé à des effets secondaires systémiques en raison d'une forte dépression neuronale. La gestion de la toxicité du baclofène consiste principalement en un traitement de soutien. Certaines études ont toutefois démontré que l'hémodialyse pourrait atténuer les symptômes d'une surdose et hâter la convalescence. PRÉSENTATION DU CAS: Nous présentons les cas d'un garçon de six ans atteint d'une légère paralysie cérébrale et d'une neuromyélite optique. L'enfant, dont la fonction rénale était normale, avait été retrouvé inconscient à son domicile, avec un état mental altéré, après avoir ingéré accidentellement 1 300 mg de baclofène. L'importante dépression neurologique et l'insuffisance respiratoire subséquente ont nécessité l'intubation et la ventilation mécanique du patient. DIAGNOSTIC: Une encéphalopathie induite par le baclofène a été diagnostiquée. Un taux très élevé de baclofène sérique, soit de 4,00 µg/mL (l'intervalle thérapeutique se situe entre 0,08 et 0,40 µg/mL), a été observé dix heures après que l'enfant ait été retrouvé inconscient. Le patient demeurait comateux, son état respiratoire s'était dégradé et ses besoins ventilatoires étaient très élevés. INTERVENTIONS: À l'unité des soins intensifs, la dégradation de l'état clinique a nécessité l'amorce d'un traitement d'hémodialyse environ 18 heures après que l'enfant ait été retrouvé inconscient. Le traitement a été administré à l'aide d'un filtre avec une membrane à haute efficacité et à haute perméabilité. Le patient a subi deux séances d'hémodialyse à neuf heures d'intervalle, avec un débit sanguin approchant les 250 mL/min. RÉSULTATS: L'enfant a lentement repris conscience moins de trois heures après le début du premier traitement d'hémodialyse, et a été extubé six heures après le deuxième traitement d'hémodialyse. NOUVEAUX RÉSULTATS: Le principal traitement dans le cas d'une intoxication au baclofène chez un enfant avec une fonction rénale normale est la prise en charge symptomatique. L'hémodialyse pourrait être envisagée en cas d'intoxication grave avec dégradation de l'état clinique. D'autres études sont toutefois nécessaires pour confirmer ce résultat.

Development of a Comprehensive Communication Skills Curriculum for Pediatrics Residents.

BACKGROUND: Effective communication is an essential element of medical care and a priority of medical education. Specific interventions to teach communication skills are at the discretion of individual residency programs. OBJECTIVE: We developed the Resident Communication Skills Curriculum (RCSC), a formal curriculum designed to teach trainees the communication skills essential for high-quality practice. METHODS: A multidisciplinary working group contributed to the development of the RCSC, guided by an institutional needs assessment, literature review, and the Accreditation Council for Graduate Medical Education core competencies. The result was a cohesive curriculum that incorporates didactic, role play, and real-life experiences over the course of the entire training period. Methods to assess curricular outcomes included self-reporting, surveys, and periodic faculty evaluations of the residents. RESULTS: Curricular components have been highly rated by residents (3.95-3.97 based on a 4-point Likert scale), and residents' self-reported communication skills demonstrated an improvement over the course of residency in the domains of requesting a consultation, providing effective handoffs, handling conflict, and having difficult conversations (intern median 3.0, graduate median 4.0 based on a 5-point Likert scale, P ≤ .002). Faculty evaluations of residents have also demonstrated improvement over time (intern median 3.0, graduate median 4.5 based on a 5-point Likert scale, P < .001). CONCLUSIONS: A comprehensive, integrated communication skills curriculum for pediatrics residents was implemented, with a multistep evaluative process showing improvement in skills over the course of the residency program. Positive resident evaluations and informal comments from faculty support its general acceptance. The use of existing resources makes this curriculum feasible.

Development of a spectroscopic technique for continuous online monitoring of oxygen and site-specific nitrogen isotopic composition of atmospheric nitrous oxide.

Nitrous oxide is an important greenhouse gas and ozone-depleting-substance. Its sources are diffuse and poorly characterized, complicating efforts to understand anthropogenic impacts and develop mitigation policies. Online, spectroscopic analysis of N2O isotopic composition can provide continuous measurements at high time resolution, giving new insight into N2O sources, sinks, and chemistry. We present a new preconcentration unit, "Stheno II", coupled to a tunable infrared laser direct absorption spectroscopy (TILDAS) instrument, to measure ambient-level variations in (18)O and site-specific (15)N N2O isotopic composition at remote sites with a temporal resolution of <1 h. Trapping of N2O is quantitative up to a sample size of ∼4 L, with an optimal sample size of 1200-1800 mL at a sampling frequency of 28 min. Line shape variations with the partial pressure of the major matrix gases N2/O2 and CO2 are measured, and show that characterization of both pressure broadening and Dicke narrowing is necessary for an optimal spectral fit. Partial pressure variations of CO2 and bath gas result in a linear isotopic measurement offset of 2.6-6.0 ‰ mbar(-1). Comparison of IR MS and TILDAS measurements shows that the TILDAS technique is accurate and precise, and less susceptible to interferences than IR MS measurements. Two weeks of measurements of N2O isotopic composition from Cambridge, MA, in May 2013 are presented. The measurements show significant short-term variability in N2O isotopic composition larger than the measurement precision, in response to meteorological parameters such as atmospheric pressure and temperature.

Fully automated, high-precision instrumentation for the isotopic analysis of tropospheric N2O using continuous flow isotope ratio mass spectrometry.

RATIONALE: Measurements of the isotopic composition of nitrous oxide in the troposphere have the potential to bring new information about the uncertain N2O budget, which mole fraction data alone have not been able to resolve. Characterizing the expected subtle variations in tropospheric N2O isotopic composition demands high-precision and high-frequency measurements. To enable useful observations of N2O isotopic composition in tropospheric air to reduce N2O source and sink uncertainty, it was necessary to develop a high-precision measurement system with fully automated capabilities for autonomous deployment at remote research stations. METHODS: A fully automated pre-concentration system for high-precision measurements of N2O isotopic composition (δ(15)N(ß) , δ(15)N(α), δ(18)O) in tropospheric air has been developed which combines a custom liquid-cryogen-free cryo-trapping system and gas chromatograph interfaced to a continuous flow isotope ratio mass spectrometry (IRMS) system. A quadrupole mass spectrometer was coupled in parallel to the IRMS system during development to evaluate peak interference. Multi-port inlet and fully-automated capabilities allow streamlined analyses between in situ air inlet, air standards, flask air sample, or other gas source in exactly replicated analysis sequences. RESULTS: The system has the highest precision to date for (15)N site-specific composition results (δ(15) N(α) ±0.11‰, δ(15)N(ß) ±0.14‰ (1σ)), attributed mostly to uniformity of analytical cycles and particular attention to fluorocarbon interference noted for (15)N site-specific measurements by IRMS. Air measurements demonstrated the fully automated capacity and performance. CONCLUSIONS: The system makes substantial headway in measurement precision, possibly defining the limits of IRMS measurement capabilities in low concentration N2O air samples, with fully automated capabilities to enable high-frequency in situ measurements.

Polybrominated diphenyl ether flame retardants in Chesapeake Bay region, U.S.A., peregrine falcon (Falco peregrinus) eggs: urban/rural trends.

A total of 23 peregrine falcon (Falco peregrinus) eggs were obtained between 1993 and 2002 from 13 nests, encompassing 11 locations in the Chesapeake Bay region, U.S.A. When multiple eggs were available from the same clutch, average clutch contaminant concentrations were calculated. An overall median total polybrominated diphenyl ether (PBDE) level of 201 ng/g wet weight was determined for the eggs/clutches examined. The maximum in an individual egg, from an urban highway bridge site, was 354 ng/g. This egg also exhibited the highest BDE 209 burden (48.2 ng/g). Compared to distributions reported in fish and piscivorous birds, falcon eggs were enriched in the more brominated congeners. The BDE congeners 153, 99, and 100 constituted 26.0, 24.8, and 13.1%, respectively, of total PBDEs. In most aquatic species, BDE 47 is the most abundant congener reported; however, it constituted only 4.4% of total PBDEs in the eggs of the present study. The median BDE 209 concentration was 6.3 ng/g. The sum of the octa- to nonabrominated congeners (BDEs 196, 197, 206, 207, and 208) contributed, on average, 14.0% of total PBDEs, exceeding the contribution of BDE 209 (5.9%). Concentrations of polychlorinated biphenyls (PCBs) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (4,4'-DDE) also were determined in a subset of 16 eggs (collected in 2001-2002 from six nests) and were an order of magnitude greater than the corresponding PBDEs. Median BDE 209 concentrations were significantly correlated (p < 0.01, Spearman R = 0.690) with the human population density of the area surrounding the nest. Total PBDEs, total PCBs, and 4,4'-DDE levels were not correlated to human population density.

Argatroban for anticoagulation in pediatric patients with heparin-induced thrombocytopenia requiring extracorporeal life support.

Heparin-induced thrombocytopenia (HIT) is a well recognized and described immune phenomenon in adults. However, pediatric data on the incidence, treatment, and complications of HIT are limited. Despite the widespread use of heparin in pediatric patients and the repeated and sustained exposures to heparin in neonates and children with congenital heart disease, HIT has been infrequently recognized and under-reported in this population. HIT is an intensely procoagulant disorder and carries significant morbidity and mortality. In this case series, we describe HIT management with argatroban as alternative anticoagulation in 3 children requiring extracorporeal life support.