Langley mobile ozone lidar: ozone and aerosol atmospheric profiling for air quality research.

The Langley mobile ozone lidar (LMOL) is a mobile ground-based ozone lidar system that consists of a pulsed UV laser producing two UV wavelengths of 286 and 291 nm with energy of approximately 0.2 mJ/pulse and repetition rate of 1 kHz. The 527 nm pump laser is also transmitted for aerosol measurements. The receiver consists of a 40 cm parabolic telescope, which is used for both backscattered analog and photon counting. The lidar is very compact and highly mobile. This demonstrates the utility of very small lidar systems eventually leading to space-based ozone lidars. The lidar has been validated by numerous ozonesonde launches and has provided ozone curtain profiles from ground to approximately 4 km in support of air quality field missions.

Factors predictive for computed tomography use and abnormality in paediatric head injuries in Australia and New Zealand.

OBJECTIVES: To investigate patient-level factors predictive for computed tomography of the brain (CTB) use and abnormality in head injured children in Australia and New Zealand. METHODS: Retrospective data from tertiary, urban/suburban and regional/rural EDs including factors predictive for CTB use and abnormality. RESULTS: Of 3072 children at 31 EDs, 212 (6.9%) had a CTB scan, of which 66 (31%) were abnormal. Increasing age, serious mechanisms of injury and decreasing Glasgow Coma Score were predictive for ordering CTB. Decreasing age was predictive for CTB abnormalities. Other factors were not. CONCLUSION: Patient-level drivers of CTB use in children in Australia and New Zealand are consistent with international data.

Profiling atmospheric water vapor using a fiber laser lidar system.

A compact, lightweight, and efficient fiber laser lidar system has been developed to measure water vapor profiles in the lower atmosphere of Earth or Mars. The line narrowed laser consist of a Tm:germanate fiber pumped by two 792 nm diode arrays. The fiber laser transmits approximately 0.5 mJ Q- switched pulses at 5 Hz and can be tuned to water vapor lines near 1.94 microm with linewidth of approximately 20 pm. A lightweight lidar receiver telescope was constructed of carbon epoxy fiber with a 30 cm Fresnel lens and an advanced HgCdTe APD detector. This system has made preliminary atmospheric measurements.

Quantifying TOLNet Ozone Lidar Accuracy during the 2014 DISCOVER-AQ and FRAPPÉ Campaigns.

The Tropospheric Ozone Lidar Network (TOLNet) is a unique network of lidar systems that measure high-resolution atmospheric profiles of ozone. The accurate characterization of these lidars is necessary to determine the uniformity of cross-instrument calibration. From July to August 2014, three lidars, the TROPospheric OZone (TROPOZ) lidar, the Tunable Optical Profiler for Aerosol and oZone (TOPAZ) lidar, and the Langley Mobile Ozone Lidar (LMOL), of TOLNet participated in the "Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality" (DISCOVER-AQ)mission and the "Front Range Air Pollution and Photochemistry Éxperiment" (FRAPPÉ)to measure ozone variations from the boundary layer to the top of the troposphere. This study presents the analysis of the intercomparison between the TROPOZ, TOPAZ, and LMOL lidars, along with comparisons between the lidars and other in situ ozone instruments including ozonesondes and a P-3B airborne chemiluminescence sensor. In terms of the range-resolving capability, the TOLNet lidars measured vertical ozone structures with an accuracy generally better than ±15% within the troposphere. Larger differences occur at some individual altitudes in both the near-field and far-field range of the lidar systems, largely as expected. In terms of column average, the TOLNet lidars measured ozone with an accuracy better than ±5% for both the intercomparison between the lidars and between the lidars and other instruments. These results indicate very good measurement accuracy for these three TOLNet lidars, making them suitable for use in air quality, satellite validation, and ozone modeling efforts.

Antiviral activity of lamivudine in salvage therapy for multidrug-resistant HIV-1 infection.

BACKGROUND: Maximum suppression of virus replication is often not achievable for persons infected with multidrug-resistant human immunodeficiency virus type 1 (HIV-1). Available data suggest that lamivudine contributes to partial viral suppression, despite the presence of M184V mutations and high-level phenotypic lamivudine resistance. METHODS: Selective lamivudine withdrawal was studied in 6 subjects who had incomplete viral suppression during antiretroviral treatment for multidrug-resistant HIV-1 infection. RESULTS: Plasma levels of HIV-1 RNA increased to 0.5 log(10) copies/mL above baseline 6 weeks after the withdrawal of lamivudine treatment (P=.04), even though reversion of lamivudine resistance was not yet detected. Early increases in plasma levels of HIV-1 RNA after lamivudine withdrawal were associated with the presence of the T215Y/F mutation and broad phenotypic resistance to nucleoside reverse-transcriptase inhibitors at baseline. Genotypic and phenotypic reversion of lamivudine resistance was detected in 4 subjects 8-14 weeks after withdrawal of lamivudine therapy. The duration of lamivudine withdrawal ranged from 8 to 22 weeks; all subjects resumed lamivudine treatment. Plasma levels of HIV-1 RNA were 0.6 log(10) copies/mL above baseline (P=.03) when lamivudine therapy was resumed. After the resumption of lamivudine treatment, plasma HIV RNA levels decreased to baseline levels in 3 subjects but remained elevated in 3 subjects who had evolution of increased antiretroviral drug resistance during the period of lamivudine withdrawal. Safety concerns raised by this latter finding led to permanent closure of the study. CONCLUSIONS: In select cases of multidrug-resistant HIV-1 infection, lamivudine contributes to suppression of HIV-1 replication, despite the presence of M184V mutations and lamivudine resistance.

Comparison of colchicine, dapsone, triamcinolone, and diphenhydramine therapy for the treatment of brown recluse spider envenomation: a double-blind, controlled study in a rabbit model.

OBJECTIVE: To compare the efficacy of dapsone, diphenhydramine, colchicine, and intralesional triamcinolone in the treatment of brown spider bites. We used a purified venom that reproducibly produces a large eschar. To mimic real-life circumstances, all agents were administered following a 2-hour delay after envenomation. The animals were evaluated for the presence of coagulopathy to determine if the incidence of systemic findings correlated with the type of treatment. DESIGN AND SETTING: In a research laboratory, 60 New Zealand white rabbits each received an intradermal injection of 20 microg of purified Loxosceles reclusa venom. The rabbits were divided into 5 groups of 12; a control group and 4 groups treated with a drug (either colchicine, triamcinolone, diphenhydramine, or dapsone). Measured end points included maximum eschar size as well as histologic grading of depth, inflammation, and thrombosis. INTERVENTIONS: Treatment with colchicine, triamcinolone, diphenhydramine, or dapsone. MAIN OUTCOME MEASURES: Maximum eschar size as well as histologic grading of depth, inflammation, and thrombosis. RESULTS: There was no significant difference with respect to eschar size (1-way analysis of variance, P = .003). There was no significant difference between any treatment with respect to presence or absence of ulcer, necrosis, large vessel vasculitis, or small vessel vasculitis. The only outcome of significance was that triamcinolone offered protection from thrombosis (chi2 likelihood ratio, P = .04). We also noted evidence of coagulopathy in all of the envenomated animals. The rabbits had grossly elevated activated partial thromboplastin time results, which were corrected with 1:1 mixing with normal rabbit plasma, suggesting an acquired factor deficiency. We did not detect an individual factor deficiency or a lupus anticoagulant. CONCLUSIONS: In a rabbit model, none of the agents tested (dapsone, diphenhydramine, colchicine, and intralesional triamcinolone) had an effect on eschar size. Triamcinolone appeared to offer some protection against histologic evidence of thrombosis, but this protection did not translate into a difference in clinical outcome. All animals developed evidence of coagulopathy, regardless of treatment. The coagulopathy could be corrected by fresh rabbit plasma, suggesting an acquired factor deficiency.

An unusual location of a pilar sheath acanthoma.

Pilar sheath acanthoma is a rare, benign follicular hamartoma that frequently presents as an asymptomatic, flesh-colored papule with a central opening. First described in 1978 by Mehregan and Brownstein, these lesions generally appear on the upper lip of elderly patients. We present an interesting case of a pilar sheath acanthoma presenting on the earlobe in a middle-aged male. To the best of our knowledge, this is the first reported case of a pilar sheath acanthoma found in such a unique location.

Aerosol transport in the California Central Valley observed by airborne lidar.

An aerosol lidar system was deployed on the NASA DC-8 and used to measure aerosol vertical profiles in the California Central Valley. The nadir-pointing Nd:YAG lidar operated at 532 and 1064 nm at 20 Hz. The resulting aerosol profiles were plotted in a unique three-dimensional format that allowed the visual observation of the aerosol scattering ratio profiles, the valley topography, and corresponding backward trajectory air masses. The accumulation of aerosols from the Bakersfield area can be seen in the southern end of the valley due to topography and prevailing winds.

Rate of thymidine analogue resistance mutation accumulation with zidovudine- or stavudine-based regimens.

Zidovudine (ZDV) and stavudine (d4T) select for the same set of thymidine analogue resistance mutations (TAMs). To compare the rate at which TAMs emerge, genotypic analysis of HIV-1 was performed on serial plasma samples from treatment-naive subjects randomly assigned to receive ZDV or d4T in combination with lamivudine. After 72 weeks of follow-up, TAMs were detected in samples from 50% of ZDV-treated subjects and 45% of d4T-treated subjects (P = 0.79). The frequency of K70R and T215Y or F mutations was similar in both groups, although M41L was observed more frequently in samples from ZDV-treated subjects. This randomized study shows that TAMs accumulate at similar rates during treatment with ZDV or d4T, but the specific pattern of mutations may differ somewhat in patients treated with these thymidine analogues.

Performance characteristics of the TRUGENE HIV-1 Genotyping Kit and the Opengene DNA Sequencing System.

The TRUGENE HIV-1 Genotyping Kit and OpenGene DNA Sequencing System are designed to sequence the protease (PR)- and reverse transcriptase (RT)-coding regions of human immunodeficiency virus type 1 (HIV-1) pol. Studies were undertaken to determine the accuracy of this assay system in detecting resistance-associated mutations and to determine the effects of RNA extraction methods, anticoagulants, specimen handling, and potentially interfering substances. Samples were plasma obtained from HIV-infected subjects or seronegative plasma to which viruses derived from wild-type and mutant infectious molecular clones (IMC) of HIV-1 were added. Extraction methods tested included standard and UltraSensitive AMPLICOR HIV-1 MONITOR, QIAGEN viral RNA extraction mini kit, and QIAGEN Ultra HIV extraction kit, and NASBA manual HIV-1 quantitative NucliSens. Sequence data from test sites were compared to a "gold standard" reference sequence to determine the percent agreement. Comparisons between test and reference sequences at the nucleotide level showed 97.5 to 100% agreement. Similar results were obtained regardless of extraction method, regardless of use of EDTA or acid citrate dextrose as anticoagulant, and despite the presence of triglycerides, bilirubin, hemoglobin, antiretroviral drugs, HIV-2, hepatitis C virus (HCV), HBV, cytomegalovirus, human T-cell leukemia virus type 1 (HTLV-1), or HTLV-2. Samples with HIV-1 RNA titers of >or=1,000 copies/ml gave consistent results. The TRUGENE HIV-1 Genotyping Kit and OpenGene DNA Sequencing System consistently generate highly accurate sequence data when tested with IMC-derived HIV and patient samples.

HIV-1-infected antiretroviral-treated patients with prolonged partial viral suppression: clinical, virologic, and immunologic course.

The long-term feasibility of a drug conservation strategy that allows low-level viral replication is unknown. We performed a retrospective study of treated HIV-infected patients with stable detectable viral replication (<10000 copies/mL [low-level viremia]) and compared their clinical, virologic and immunologic courses with those of treated patients with undetectable viremia and viremia (>or=10000 copies/mL [high-level viremia]). Viral reverse transcriptase and protease genotype and HIV-specific CD4 T-cell responses were determined using patient-derived samples. Clinical and immunologic benefits were maintained in patients with partial virologic suppression (or=2 classes of antiretroviral medications. HIV-specific CD4+ T-cell immunity was detected in most subjects with low-level and undetectable viremia and may have a role in controlling viremia in the setting of partial suppression.