Coronavirus Disease 2019 in Patients With End-Stage Kidney Disease on Hemodialysis in Guatemala.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) is public health concern across the world. Data on the epidemiology among patients on hemodialysis in Latin America and low- and middle-income countries are limited. METHODS: Using electronic medical records from the second largest dialysis network in Guatemala, we performed a retrospective analysis of all adult patients on hemodialysis with the diagnosis of COVID-19 to estimate incidence of infection and to describe the demographics, comorbidities, and outcomes. We stratified incidence rate by region. We reviewed data from May 1 to July 31, 2020, with outcome data ascertained up to August 28, 2020. RESULTS: Of 3201 patients undergoing hemodialysis, 325 patients were diagnosed with COVID-19 (incidence rate 102/1000 patients on hemodialysis, compared with 3/1000 in the general population). Incidence was higher in the Central region (207/1000) and lowest in the Southeast region (33/1000), and unlike in the general population, the incidence was lower in Guatemala City. The mean age of patients diagnosed with COVID-19 was 51.1 years (standard deviation [SD] 14.8 years), and 84 (25.8%) were female. The median length of hospital stay was 12 days (interquartile range [IQR] 10-16 days). Two hundred twenty-nine (69.8%) of the patients recovered, 90 patients died (27.7%), and 6 (1.8%) patients were still in the hospital at the time of last follow-up. CONCLUSION: The incidence of diagnosed COVID-19 in Guatemalan patients on hemodialysis was much higher than reported in the general population, with outcomes similar to those described in high-income countries. Rural regions had higher incidence rates than the major metropolitan area.

Reconciling Assumptions in Bottom-Up and Top-Down Approaches for Estimating Aerosol Emission Rates From Wildland Fires Using Observations From FIREX-AQ.

Accurate fire emissions inventories are crucial to predict the impacts of wildland fires on air quality and atmospheric composition. Two traditional approaches are widely used to calculate fire emissions: a satellite-based top-down approach and a fuels-based bottom-up approach. However, these methods often considerably disagree on the amount of particulate mass emitted from fires. Previously available observational datasets tended to be sparse, and lacked the statistics needed to resolve these methodological discrepancies. Here, we leverage the extensive and comprehensive airborne in situ and remote sensing measurements of smoke plumes from the recent Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) campaign to statistically assess the skill of the two traditional approaches. We use detailed campaign observations to calculate and compare emission rates at an exceptionally high-resolution using three separate approaches: top-down, bottom-up, and a novel approach based entirely on integrated airborne in situ measurements. We then compute the daily average of these high-resolution estimates and compare with estimates from lower resolution, global top-down and bottom-up inventories. We uncover strong, linear relationships between all of the high-resolution emission rate estimates in aggregate, however no single approach is capable of capturing the emission characteristics of every fire. Global inventory emission rate estimates exhibited weaker correlations with the high-resolution approaches and displayed evidence of systematic bias. The disparity between the low-resolution global inventories and the high-resolution approaches is likely caused by high levels of uncertainty in essential variables used in bottom-up inventories and imperfect assumptions in top-down inventories.

Chemical composition by HPLC-ESI-QTOF-MS/MS: Estrogenic and antioxidant effects of Mangifera indica L. cv. "Kent" leave extracts on ovariectomized rats / Composición química por HPLC-ESI-QTOF-MS/MS: efectos estrogénicos y antioxidantes de extractos de Mangifera indica L. cv. "Kent" en ratas ovariectomizadas

The chemical composition of Mangifera indica L. cv. "Kent" leaves was determined by HPLC-ESI-QTOF-MS/MS. Polyphenolic compounds characterized as benzophenone derivatives were the main components found in extracts (1, maclurin 3-C-(2-O-galloyl)-D- glucoside isomer; 2, maclurin 3-C---D-glucoside; 3, iriflophenone 3-C---D-glucoside; 5, maclurin 3-C-(2,3-di-O-galloyl)---D-glucoside; 6, iriflophenone 3-C-(2-O-galloyl)---D-glucoside; 7, methyl-iriflophenone 3-C-(2,6-di-O-galloyl)---D-glucoside) and xanthones (4, mangiferin and 8, 6-O-galloyl-mangiferin). The estrogenic and antioxidant effects of aqueous extracts from Mangifera indica L. cv. "Kent" leaves on ovariectomized rats were determined by uterotrophic assay and malondialdehyde (MDA) levels in erythrocytes, bone, liver, and stomach. We conclude that the polyphenolic compounds from extracts act as exogenous antioxidant agents against oxidative damage in ovariectomized rats.

La composición química de las hojas de Mangifera indica L. cv. "Kent" se determinó por HPLC-ESI-QTOF-MS/MS. Compuestos polifenólicos caracterizados como derivados de benzofenona fueron los componentes principales encontrados en los extractos (1, isómero de la maclurina 3-C-(2-O-galoyil)-D-glucósido; 2, maclurina 3-C-ß-D-glucósido; 3, iriflofenona 3-C-ß-D-glucósido; 5, maclurina 3-C-(2,3-di-O-galloíl)-ß-D-glucósido; 6, iriflofenona 3-C-(2-O-galloil)-ß-D-glucósido; 7, metil-iriflofenona 3-C-(2,6-di-O- galloyl)-ß-D-glucósido) y xantonas (4, mangiferina y 8, 6-O-galoyil-mangiferina). Los efectos estrogénicos y antioxidantes de los extractos acuosos de hojas de Mangifera indica L. cv. "Kent" en ratas ovariectomizadas se determinaron mediante ensayo uterotrófico y la medición de los niveles de malondialdehído (MDA) en eritrocitos, huesos, hígado y estómago. Concluimos que los compuestos polifenólicos de los extractos actúan como agentes antioxidantes exógenos contra el daño oxidativo en ratas ovariectomizadas.

Calibration of a high spectral resolution lidar using a Michelson interferometer, with data examples from ORACLES.

The NASA Langley airborne second-generation High Spectral Resolution Lidar (HSRL-2) uses a density-tuned field-widened Michelson interferometer to implement the HSRL technique at 355 nm. The Michelson interferometer optically separates the received backscattered light between two channels, one of which is dominated by molecular backscattering, while the other contains most of the light backscattered by particles. This interferometer achieves high and stable contrast ratio, defined as the ratio of particulate backscatter signal received by the two channels. We show that a high and stable contrast ratio is critical for precise and accurate backscatter and extinction retrievals. Here, we present retrieval equations that take into account the incomplete separation of particulate and molecular backscatter in the measurement channels. We also show how the accuracy of the contrast ratio assessment propagates to error in the optical properties. For both backscattering and extinction, larger errors are produced by underestimates of the contrast ratio (compared to overestimates), more extreme aerosol loading, and-most critically-smaller true contrast ratios. We show example results from HSRL-2 aboard the NASA ER-2 aircraft from the 2016 ORACLES field campaign in the southeast Atlantic, off the coast of Africa, during the biomass burning season. We include a case study where smoke aerosol in two adjacent altitude layers showed opposite differences in extinction- and backscatter-related Ångström exponents and a reversal of the lidar ratio spectral dependence, signatures which are shown to be consistent with a relatively modest difference in smoke particle size.

Photochemical model evaluation of 2013 California wild fire air quality impacts using surface, aircraft, and satellite data.

The Rim Fire was one of the largest wildfires in California history, burning over 250,000 acres during August and September 2013 affecting air quality locally and regionally in the western U.S. Routine surface monitors, remotely sensed data, and aircraft based measurements were used to assess how well the Community Multiscale Air Quality (CMAQ) photochemical grid model applied at 4 and 12 km resolution represented regional plume transport and chemical evolution during this extreme wildland fire episode. Impacts were generally similar at both grid resolutions although notable differences were seen in some secondary pollutants (e.g., formaldehyde and peroxyacyl nitrate) near the Rim fire. The modeling system does well at capturing near-fire to regional scale smoke plume transport compared to remotely sensed aerosol optical depth (AOD) and aircraft transect measurements. Plume rise for the Rim fire was well characterized as the modeled plume top was consistent with remotely sensed data and the altitude of aircraft measurements, which were typically made at the top edge of the plume. Aircraft-based lidar suggests O3 downwind in the Rim fire plume was vertically stratified and tended to be higher at the plume top, while CMAQ estimated a more uniformly mixed column of O3. Predicted wildfire ozone (O3) was overestimated both at the plume top and at nearby rural and urban surface monitors. Photolysis rates were well characterized by the model compared with aircraft measurements meaning aerosol attenuation was reasonably estimated and unlikely contributing to O3 overestimates at the top of the plume. Organic carbon was underestimated close to the Rim fire compared to aircraft data, but was consistent with nearby surface measurements. Periods of elevated surface PM2.5 at rural monitors near the Rim fire were not usually coincident with elevated O3.

Simultaneous polarimeter retrievals of microphysical aerosol and ocean color parameters from the "MAPP" algorithm with comparison to high-spectral-resolution lidar aerosol and ocean products.

We present an optimal-estimation-based retrieval framework, the microphysical aerosol properties from polarimetry (MAPP) algorithm, designed for simultaneous retrieval of aerosol microphysical properties and ocean color bio-optical parameters using multi-angular total and polarized radiances. Polarimetric measurements from the airborne NASA Research Scanning Polarimeter (RSP) were inverted by MAPP to produce atmosphere and ocean products. The RSP MAPP results are compared with co-incident lidar measurements made by the NASA High-Spectral-Resolution Lidar HSRL-1 and HSRL-2 instruments. Comparisons are made of the aerosol optical depth (AOD) at 355 and 532 nm, lidar column-averaged measurements of the aerosol lidar ratio and Ångstrøm exponent, and lidar ocean measurements of the particulate hemispherical backscatter coefficient and the diffuse attenuation coefficient. The measurements were collected during the 2012 Two-Column Aerosol Project (TCAP) campaign and the 2014 Ship-Aircraft Bio-Optical Research (SABOR) campaign. For the SABOR campaign, 73% RSP MAPP retrievals fall within ±0.04 AOD at 532 nm as measured by HSRL-1, with an R value of 0.933 and root-mean-square deviation of 0.0372. For the TCAP campaign, 53% of RSP MAPP retrievals are within 0.04 AOD as measured by HSRL-2, with an R value of 0.927 and root-mean-square deviation of 0.0673. Comparisons with HSRL-2 AOD at 355 nm during TCAP result in an R value of 0.959 and a root-mean-square deviation of 0.0694. The RSP retrievals using the MAPP optimal estimation framework represent a key milestone on the path to a combined lidar+polarimeter retrieval using both HSRL and RSP measurements.

The MERRA-2 Aerosol Reanalysis, 1980 - onward, Part I: System Description and Data Assimilation Evaluation.

The Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2) updates NASA's previous satellite era (1980 - onward) reanalysis system to include additional observations and improvements to the Goddard Earth Observing System, Version 5 (GEOS-5) Earth system model. As a major step towards a full Integrated Earth Systems Analysis (IESA), in addition to meteorological observations, MERRA-2 now includes assimilation of aerosol optical depth (AOD) from various ground- and space-based remote sensing platforms. Here, in the first of a pair of studies, we document the MERRA-2 aerosol assimilation, including a description of the prognostic model (GEOS-5 coupled to the GOCART aerosol module), aerosol emissions, and the quality control of ingested observations. We provide initial validation and evaluation of the analyzed AOD fields using independent observations from ground, aircraft, and shipborne instruments. We demonstrate the positive impact of the AOD assimilation on simulated aerosols by comparing MERRA-2 aerosol fields to an identical control simulation that does not include AOD assimilation. Having shown the AOD evaluation, we take a first look at aerosol-climate interactions by examining the shortwave, clear-sky aerosol direct radiative effect. In our companion paper, we evaluate and validate available MERRA-2 aerosol properties not directly impacted by the AOD assimilation (e.g. aerosol vertical distribution and absorption). Importantly, while highlighting the skill of the MERRA-2 aerosol assimilation products, both studies point out caveats that must be considered when using this new reanalysis product for future studies of aerosols and their interactions with weather and climate.

The MERRA-2 Aerosol Reanalysis, 1980 Onward. Part II: Evaluation and Case Studies.

The Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), is NASA's latest reanalysis for the satellite era (1980 onward) using the Goddard Earth Observing System, version 5 (GEOS-5), Earth system model. MERRA-2 provides several improvements over its predecessor (MERRA-1), including aerosol assimilation for the entire period. MERRA-2 assimilates bias-corrected aerosol optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer and the Advanced Very High Resolution Radiometer instruments. Additionally, MERRA-2 assimilates (non bias corrected) AOD from the Multiangle Imaging SpectroRadiometer over bright surfaces and AOD from Aerosol Robotic Network sunphotometer stations. This paper, the second of a pair, summarizes the efforts to assess the quality of the MERRA-2 aerosol products. First, MERRA-2 aerosols are evaluated using independent observations. It is shown that the MERRA-2 absorption aerosol optical depth (AAOD) and ultraviolet aerosol index (AI) compare well with Ozone Monitoring Instrument observations. Next, aerosol vertical structure and surface fine particulate matter (PM2.5) are evaluated using available satellite, aircraft, and ground-based observations. While MERRA-2 generally compares well to these observations, the assimilation cannot correct for all deficiencies in the model (e.g., missing emissions). Such deficiencies can explain many of the biases with observations. Finally, a focus is placed on several major aerosol events to illustrate successes and weaknesses of the AOD assimilation: the Mount Pinatubo eruption, a Saharan dust transport episode, the California Rim Fire, and an extreme pollution event over China. The article concludes with a summary that points to best practices for using the MERRA-2 aerosol reanalysis in future studies.

Dose determination of a novel formulation of metaflumizone plus amitraz for control of cat fleas (Ctenocephalides felis felis) and brown dog ticks (Rhipicephalus sanguineus) on dogs.

A novel spot-on formulation containing metaflumizone and amitraz (ProMeris/ProMeris Duo for Dogs, Fort Dodge Animal Health, Overland Park, KS) was evaluated in a laboratory study to determine the appropriate dose for efficacy against fleas and ticks on dogs for 1 month. Thirty-six Beagles were randomly allocated to six equal groups and individually housed. One group remained nontreated. Another was treated with a placebo formulation (solvents with no active ingredients). Three groups of dogs were treated topically with the metaflumizone plus amitraz formulation (150mg of each of metaflumizone and amitraz/ml), at volumes providing doses of 10, 20 and 40mgeachactive/kg. The final group was treated with a commercial spot-on providing 6.7mgfipronil/kg. All treatments were applied to the skin at a single spot between the scapulae on Day 0. Dogs were infested with 50 adult brown dog ticks (Rhipicephalus sanguineus) on each of Days -2, 5, 12, 19, 26, 33 and 40, and with 100 cat fleas (Ctenocephalides felis felis) on Days -1, 6, 13, 20, 27, 34 and 41. Dogs were examined and parasites "finger counted" on Day 1 to estimate knock down efficacy, and all animals were comb counted to determine the numbers of viable fleas and ticks on Days 7, 14, 21, 28, 35 and 42. There were no significant differences in parasite counts between the nontreated control and the placebo-treated control groups for either fleas or ticks (P>0.05) except for very slight reductions on Day 7 for fleas and Day 14 for ticks, demonstrating that the formulation excipients had no activity. The qualitative finger counts on Day 1 indicated that all of the insecticidal treatments resulted in a noticeable reduction in flea and tick numbers within 1 day of treatment. All of the metaflumizone and amitraz treatments and fipronil resulted in significantly lower flea and tick numbers relative to nontreated controls on all posttreatment count days (P<0.05). For the metaflumizone plus amitraz treatments, mean flea and tick counts for the 10mg/kg dose were significantly higher than those for the 20mg/kg dose (P<0.05) from Day 21 on. There was no significant advantage provided by the 40mg/kg dose over the 20mg dose throughout the entire study (P>0.05). The two higher metaflumizone plus amitraz doses provided >95% control of fleas and >90% control of ticks for at least 35 days after treatment, and this level of control was similar to that of the commercial fipronil product. The 20mg/kg dose was selected as the minimum commercial dose rate to provide effective flea and tick control for at least 1 month following a single treatment.

Efficacy of a novel formulation of metaflumizone for the control of fleas (Ctenocephalides felis) on cats.

A novel spot-on formulation containing metaflumizone (ProMeris for Cats, Fort Dodge Animal Health, Overland Park, KS) was evaluated in five laboratory studies to determine the duration of residual efficacy in cats against fleas after a single spot treatment. In each study, eight domestic shorthair cats were randomly allocated to each treatment group and individually housed. One group in each study remained non-treated. In one study, an additional group of eight cats was treated with a placebo formulation. Cats were treated topically with metaflumizone formulation to provide a dose of at least 40mg metaflumizone/kg. Cats were infested with 100 cat fleas (Ctenocephalides felis felis) once per week for approximately 8 weeks. Cats were comb counted 48h after treatment and each infestation to determine the number of viable fleas present. There were no significant differences in flea counts between the non-treated control and the placebo-treated control (P>0.05) other than a 26% reduction at week 1, demonstrating that the formulation excipients had no activity. Metaflumizone treatment resulted in significantly lower flea numbers relative to non-treated controls on all post-treatment count days (P<0.05). Metaflumizone provided >90% control of flea infestations up to 7 weeks following a single treatment.

Confirmation of the efficacy of a novel formulation of metaflumizone plus amitraz for the treatment and control of fleas and ticks on dogs.

A novel spot-on formulation containing metaflumizone plus amitraz (ProMeris/ProMeris Duo for Dogs, Fort Dodge Animal Health, Overland Park, KS) was evaluated in four laboratory studies to confirm efficacy against fleas and ticks on dogs for 1 month. Three different strains of cat flea (Ctenocephalides felis felis) and four tick species were used. Rhipicephalus sanguineus and Dermacentor variabilis were evaluated concurrently in two studies and Ixodes scapularis and Amblyomma americanum in one study each. In all studies, dogs were randomly allocated to treatment groups and compared with nontreated dogs. One study also included a placebo treatment and a commercial product containing fipronil plus S-methoprene. All treatments were applied to the skin at a single spot between the scapulae on Day 0. Dogs were infested with fleas and/or ticks prior to treatment and then reinfested at weekly intervals for 6 weeks after treatment and evaluated for efficacy at 1 or 2 days after treatment and each reinfestation. These studies confirmed that treatment with ProMeris for Dogs at the proposed commercial dose rate rapidly controlled existing infestations of fleas and ticks on dogs. Treatment provided control of reinfesting fleas for up to 6 weeks and at least 4 weeks control of ticks. Efficacy was confirmed in a variety of dog breeds against three different flea strains and four common species of ticks found on dogs in the United States.

Efficacy and safety of topical administration of selamectin for treatment of ear mite infestation in rabbits.

OBJECTIVE: To evaluate the efficacy and safety of topical administration of selamectin in rabbits naturally infested with Psoroptes cuniculi. DESIGN: Randomized controlled trial. ANIMALS: 48 mixed-breed domestic rabbits with active P. cuniculi mite populations and clinical ear lesions. PROCEDURES: Rabbits were randomly allocated to 1 of 6 treatment groups. On day 0, rabbits in groups 1 and 2 were given vehicle, rabbits in groups 3 and 4 were given selamectin at a dose of 6 mg/kg (2.7 mg/lb), and rabbits in groups 5 and 6 were given selamectin at a dose of 18 mg/kg (8.2 mg/lb). On day 28, rabbits in groups 2, 4, and 6 were given a second dose of vehicle or selamectin. Otoscopic examinations were performed and ear lesion size was measured weekly for 8 weeks. Quantitative viable mite counts were performed on day 56. RESULTS: On days 7 through 56, lesion sizes for all selamectin-treated groups were significantly lower than sizes for control groups; there were no significant differences in lesion sizes among selamectin-treated groups. All rabbits in the 2 control groups had viable adult P. cuniculi mites for the duration of the study, as determined by otoscopic examination, whereas all rabbits in the 4 selamectin-treated groups were free from P. cuniculi mites on days 7 through 56. No adverse reactions associated with selamectin treatment were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that topical application of selamectin at a dose of 6 or 18 mg/kg can completely eliminate mites from rabbits naturally infested with P. cuniculi.

Efficacy of two 65% permethrin spot-on formulations against induced infestations of Ctenocephalides felis (Insecta: Siphonaptera) and Amblyomma americanum (Acari: Ixodidae) on beagles.

The efficacy of two formulations of a topically applied 65% permethrin spot-on (Defend Exspot Treatment for Dogs, Schering-Plough Animal Health) was evaluated against experimental infestations of the cat flea Ctenocephalides felis and the lone star tick Amblyomma americanum in dogs. Eighteen dogs were randomly assigned to treatment with 65% permethrin in either diethylene glycol monomethyl ether (DGME; original formulation) or propylene glycol monomethyl ether (PGME) or to be untreated as a control. Treated dogs received either 1 (body weight < 15 kg) or 2 ml (body weight > or =15 kg) of the assigned formulation on Day 0. One hundred unfed, adult C. felis were placed on each dog on Days -6, -1, 4, 11, 18, 25, and 32. Fifty unfed, adult ticks were placed on each dog on Days -1, 3, 9, 16, 23, and 30. Live fleas and ticks were counted and removed on Days 3, 7, 14, 21, and 28. Treatment of dogs with the 65% permethrin in DGME reduced flea numbers by 90.4% to 99.9% from Days 3 through 21 (P < or =.05) and by 48.2% 28 days after treatment. Treatment of dogs with 65% permethrin in PGME reduced flea numbers by 93.7% to 99.7% from Days 3 through 28 and by 78.4% 35 days after treatment (P < or =.05). Treatment with 65% permethrin in DGME reduced tick numbers by 90% or more only on Day 7, whereas treatment with 65% permethrin in PGME reduced the number of live ticks by 90%or more on Days 7 and 14 and approached 90%(87.9%) on Day 21. Efficacy against fleas and ticks for the PGME formulation was significantly better (P < or =.05) than for the DGME formulation on Day 28. Findings in this study indicate that both the DGME and PGME formulations of 65% permethrin performed well in reducing numbers of live C. felis and A. americanum on laboratory beagles; however, the PGME formulation was effective approximately 1 to 2 weeks longer than the DGME formulation.

Efficacy of a 1% lambdacyhalothrin cattle Pour-on (Saber) against sucking and biting lice infesting beef cattle.

Four studies were conducted to determine the efficacy of a 1% lambdacyhalothrin pour-on (Saber Pour-on, Schering-Plough Animal Health) for control of sucking lice (Linognathus vituli, Haematopinus eurysternus, Solenopotes capillatus) and biting lice (Damalinia bovis) on beef cattle. Seventy-four mixed-breed cattle naturally infested with one or more species of lice at locations in Wisconsin, Nebraska, Oklahoma, and North Dakota were included in the study. Pretreatment lice samples were taken and identified by genus with the exception that sucking lice were not identified by genus at the North Dakota site. In January or February, half of the cattle at each location received a single application of 1% lambdacyhalothrin pour-on at 10 ml per head for cattle weighing less than 273 kg (600 lb) or 15 ml per head for cattle weighing 273 kg or more. The other cattle at each site served as untreated controls. Lice on designated body areas were counted 2, 4, 6, and 8 weeks after treatment, and the sum of all lice observed on each counting area was reported for each animal. The collective efficacy 6 weeks after treatment against three species of sucking lice (L. vituli, H. eurysternus, S. capillatus) was 88.4% at the Wisconsin site, 92.0% at the North Dakota site, and 100% at the Nebraska and Oklahoma sites. The 1% lambdacyhalothrin pour-on eliminated all biting lice within 2 weeks after treatment, and no biting lice were detected 8 weeks after treatment. A single treatment of 1% lambdacyhalothrin pour-on administered when lice populations were highest (January or February) provided effective season-long control of both biting and sucking lice on cattle.

Efficacy of three dose volumes of topically applied 65% permethrin against Ctenocephalides felis and Rhipicephalus sanguineus on dogs weighing 30 kg or more.

Twenty-five dogs were evenly and randomly allocated by weight to five treatment groups: untreated control, 2 ml 65% permethrin (dogs weighing 15 to 29 kg, "average dogs"), and 2, 3, or 4 ml 65% permethrin (dogs weighing > or = 30 kg, "big dogs"). Each dog was infested with 125 unfed, adult cat fleas, Ctenocephalides felis, and 50 unfed, adult brown dog ticks, Rhipicephalus sanguineus, on Days -3 (ticks only), -2 (fleas only), 3, 7, 14, 17, 21, 24, and 28. Fleas and ticks were counted 1 and 3 or 4 days after each infestation. The duration of efficacy (defined as >90%) against C. felis was 28 to 31 days. The efficacy against fleas 31 days after application of 2, 3, or 4 ml on big dogs ranged from 79.1% (2 ml) to 100% (4 ml). Big dogs that received either 3 or 4 ml of 65% permethrin had significantly (P < or = .05) fewer fleas at several evaluations between 15 and 31 days after treatment. The duration of efficacy against R. sanguineus was 15 (2 ml for big dogs) to 28 (2 ml for average dogs) days. The efficacy against R. sanguineus 28 days after treatment ranged from 79.1% (2 ml on big dogs) to 94.1% (2 ml on average dogs). Significantly (P < or = .05) fewer ticks were present at several evaluations after treatment on big dogs that received 3 or 4 ml than were present on big dogs treated with 2 ml. No significant differences were detected between the 3- and 4-ml groups from Days 10 to 31; however, the geometric mean number of ticks in the group treated with 4 ml was numerically lower than that for dogs treated with 3 ml on several occasions. These data indicate that a dose volume of 3 or 4 ml of 65% permethrin is needed to obtain an adequate level and duration of efficacy against both C. felis and R. sanguineus on dogs weighing 30 kg or more.

High-spectral-resolution lidar with iodine-vapor filters: measurement of atmospheric-state and aerosol profiles.

A high-spectral-resolution lidar can measure vertical profiles of atmospheric temperature, pressure, the aerosol backscatter ratio, and the aerosol extinction coefficient simultaneously. We describe a system with these characteristics. The transmitter is a narrow-band (FWHM of the order of 74 MHz), injection-seeded, pulsed, double YAG laser at 532 nm. Iodine-vapor filters in the detection system spectrally separate the molecular and aerosol scattering and greatly reduce the latter (-41 dB). Operating at a selected frequency to take advantage of two neighboring lines in vapor filters, one can obtain a sensitivity of the measured signal-to-air temperature ratio equal to 0.42%/K. Using a relatively modest size transmitter and receiver system (laser power times telescope aperture equals 0.19 Wm(2)), our measured temperature profiles (0.5-15 km) over 11 nights are in agreement with balloon soundings to within 2.0 K over an altitude range of 2-5 km. There is good agreement in the lapse rates, tropopause altitudes, and inversions. In principle, to invert the signal requires a known density at one altitude, but in practice it is convenient to also use a known temperature at that altitude. This is a scalable system for high spatial resolution of vertical temperature profiles in the troposphere and lower stratosphere, even in the presence of aerosols.

The efficacy of selamectin in the treatment of naturally acquired aural infestations of otodectes cynotis on dogs and cats.

The efficacy of a novel avermectin, selamectin, was evaluated against naturally acquired aural infestations of Otodectes cynotis on dogs and cats. In four controlled and masked studies conducted in the USA and Europe, animals were allocated randomly to treatment with either selamectin at a minimum dosage of 6mgkg(-1) (range, 6-12. 5mgkg(-1)) or the vehicle only from the commercial formulation of selamectin (negative control). Treatments were administered topically in a single spot to the skin of each animal's back at the base of the neck in front of the scapulae. Cats were treated on day 0 only, and dogs were treated either on day 0 only or on days 0 and 30. The ears of dogs were examined otoscopically on day 14 for the presence of viable mites. Mite counts were conducted on day 30 for animals that had received one dose and on day 60 for animals that had received two doses. Percentage reductions in geometric mean mite counts for selamectin treatment compared with the vehicle were 100% for all animals on all count days. Analysis of variance, confirmed by Savage Scores, showed that ln(mite count+1) values were significantly (P< or =0.0015) lower for selamectin than for the vehicle for all animals on all count days. Thus, selamectin administered topically at a minimum dosage of 6mgkg(-1) was safe and 100% effective against naturally acquired aural infestations of O. cynotis in dogs and cats after a single dose or after two doses administered 1 month apart.

Efficacy of selamectin against experimentally induced tick (Rhipicephalus sanguineus and Dermacentor variabilis) infestations on dogs.

Seven controlled studies were conducted to investigate the efficacy of selamectin against weekly infestations of dogs with Rhipicephalus sanguineus and Dermacentor variabilis. Treatments (selamectin or vehicle alone) were applied topically at weekly, 2-week, or monthly intervals or in a "Monthly Plus" regimen (monthly treatment with an additional treatment at 14 days after the first treatment). Selamectin was supplied in unit dose tubes designed to deliver a minimum dosage of 6mgkg(-1). The studies ranged in duration from 37 to 90 days. Fifty adult ticks (+/-2) were applied approximately weekly, and tick counts were performed 3, 4, and 5 days after each infestation. The efficacy of selamectin was expressed as the percentage reduction in geometric mean tick counts on selamectin-treated dogs compared with those for dogs treated with the vehicle alone (negative-control). In one study, the engorgement of Dermacentor variabilis was assessed by weighing ticks after removal on the fifth day after each infestation. Weekly and 2-week interval treatments with selamectin provided efficacies against R. sanguineus of >89% across the entire study periods, with 100% efficacy being achieved from 21 days after the first dose and thereafter (study duration, 37 days for the weekly regimen and 44 days for the 2-week interval regimen). D. variabilis also was well controlled by the 2-week interval treatment regimen, with >96% efficacy being achieved from 21 days after the first treatment and thereafter until the end of the study (study duration: 90 days). In five of six studies incorporating three treatments at monthly intervals, the percentage reduction in R. sanguineus and D. variabilis counts 5 days after infestation ranged from 90 to 100% in the second and third months after treatment began. In the sixth study, reductions of > or =95% in D. variabilis counts 5 days after infestation were achieved for 2 weeks after each treatment in the second and third months. For the Monthly Plus regimen, from the second treatment (day 14) onwards, selamectin achieved 83-100% reductions in R. sanguineus and D. variabilis counts 3 days after infestation, and 94-100% reductions 5 days after infestation in three of the four studies. In the fourth study, selamectin demonstrated good efficacy against D. variabilis for 2 weeks after each treatment. In all seven studies, the counts from the selamectin-treated dogs were significantly (P< or =0.018) lower than those from the vehicle-treated dogs on 77 of the 80 assessments made 5 days after infestation. Selamectin also significantly (P< or =0.0105) reduced engorgement of female D. variabilis. These studies demonstrated that selamectin, administered topically to the skin in a single spot at a minimum dosage of 6mgkg(-1) at monthly intervals, was effective in the control of experimentally induced R. sanguineus and D. variabilis infestations on dogs.

B-cell antigens within normal and activated human T cells.

In this study we compared cell surface staining for human peripheral blood lymphocyte (PBL) CD antigens by flow cytometry, with staining obtained following permeabilization of PBL using the Cytoperm method (Serotec). Six CD antigens (CD20, CD21, CD22, CD32, CD35 and major histocompatibility complex class II antigen) normally found on the surface of B cells, were also found to be expressed within T cells. We also showed, by immunoelectron microscopy, that these inappropriately expressed ('occult') CD antigens are located within cytoplasmic vesicles or within the rough endoplasmic reticulum. Following in vitro activation of T cells a distinct increase in expression of all of these cytoplasmic antigens was observed but staining at the cell surface was, by comparison, weak. We therefore propose that up-regulation of various B-cell CD antigens occurs within the cytoplasm of T cells following activation and that these antigens may be synthesized and released into the fluid-phase as soluble immunoregulatory molecules.