To determine whether acetaminophen affects the duration or severity of childhood varicella.
Randomized, double-blind, placebo-controlled trial.
Office- and hospital-based pediatric practices.
...Seventy-two children between 1 and 12 years of age entered the study. One child was withdrawn because of high fever, and three children did not complete the study; 31 received placebo and 37 received acetaminophen.
Acetaminophen, 10 mg/kg/dose, was given at 8 AM, 12 PM, 4 PM, and 8 PM for 4 days. Placebo was given to the control group. Itching, appetite, activity, and overall condition were measured for 6 days. The time to last vesicle formation, time to total scabbing, and time to total healing were measured until complete resolution of the exanthem.
The following results were better in the placebo group (p less than .05): time to total scabbing 5.6 days (SD 2.5) versus 6.7 days (SD 2.3) in the acetaminophen group, and itching on day 4 in the placebo group (symptom score 2.9 (SD 0.20) vs 2.2 (SD 0.26. Activity was better in the acetaminophen group on day 2 (3.13 (SD 0.23) vs 2.82 (SD 0.24.
These results provide evidence that acetaminophen does not alleviate symptoms in children with varicella and may prolong illness.
The anti-oxidant enzyme system protects cellular macromolecules against damage from reactive oxygen species. One component of this system, manganese superoxide dismutase (MnSOD), has also been shown ...to display tumor suppressor gene-like activity. The purpose of this study was to examine changes in MnSOD expression during hamster cheek pouch carcinogenesis, and the effects of MnSOD overexpression using an adenoviral vector. Tumor induction was carried out using 7,12-dimethylbenzαanthracene. Animals were killed at periodic intervals, and check pouch tissues were excised and examined for MnSOD expression by immunohistochemistry and digital image analysis. We observed a reduction in MnSOD expression as early as 2 weeks after the start of carcinogen application. Low MnSOD expression persisted until the end of the 23-week experimental period. Solid hamster cheek pouch carcinoma xenografts were then established in nude mice. An adenoviral vector encoding the human MnSOD gene was delivered to the xenografts by direct injection. We observed high, immediate expression of MnSOD in the xenografts that persisted for 10 days following cessation of viral construct delivery. Delivery of the MnSOD construct resulted in a maximal 50% reduction in tumor growth compared with untreated controls. Our results suggest that MnSOD may be a tumor suppressor gene in the hamster cheek pouch model system.
Cloud water deposition was estimated at three high-elevation sites in the Appalachian Mountains of the eastern United States (Whiteface Mountain, NY; Whitetop Mountain, VA; and Clingman's Dome, TN) ...from 1994 through 1999 as part of the Mountain Acid Deposition Program (MADPro). This paper provides a summary of cloud water chemistry, cloud liquid water content, cloud frequency, estimates of cloud water deposition of sulfur and nitrogen species, and estimates of total deposition of sulfur and nitrogen at these sites. Other cloud studies in the Appalachians and their comparison to MADPro are also summarized. Whiteface Mountain exhibited the lowest mean and median concentrations of sulfur and nitrogen ions in cloud water, while Clingman's Dome exhibited the highest mean and median concentrations. This geographic gradient is partly an effect of the different meteorological conditions experienced at northern versus southern sites in addition to the difference in pollution content of air masses reaching the sites. All sites measured seasonal cloud water deposition rates of SO
4
2−
greater than 50 kg/ha and NO
3
−
rates of greater than 25 kg/ha. These high-elevation sites experienced additional deposition loading of SO
4
2−
and NO
3
−
on the order of 6-20 times greater compared with lower elevation Clean Air Status and Trends Network (CASTNet) sites. Approximately 80- 90% of this extra loading is from cloud deposition.
To evaluate the effect of long-term bronchodilator therapy in CF patients with demonstrated bronchial hyperresponsiveness, we first performed methacholine challenges to determine responsiveness, then ...entered 27 patients (16 methacholine responders and 11 nonresponders) into a two-month double-blind crossover trial of albuterol, 90 μg by inhalation four times a day vs placebo. Among the responders, daily PEFR measures improved significantly more during treatment with albuterol (12 ± 32 L/min) than with placebo (–0.4 ± 19 L/min; p<0.05). In addition, a clinically important level of improvement in PEFR (15 percent increase) was reached significantly more frequently in the responders. Methacholine nonresponders had no change in PEFR on either albuterol or placebo. Daily symptom scores as well as spirometry measurements at biweekly visits did not show significant changes. We conclude that long-term therapy with inhaled albuterol improves lung function in CF patients, but only in those with bronchial hyperresponsiveness as demonstrated by methacholine challenge. (Chest 1991; 99:1088-92)
An automated cloud water collection system for unattended operation at remote sites is described. This system consists of a cloud water collector, sample accumulator, sample storage unit, and ...electronic control unit. Threshold values for liquid water content, wind speed, and temperature were set with the electronic control unit to initiate automatic collection of cloud water samples. The automated system was tested in the summer of 1994 at two remote sites: Whitetop Mountain, VA, and Whiteface Mountain, NY. During this period, it successfully collected 449 hourly cloud water samples.
A predominantly rural ozone monitoring network was operated under the auspices of the Clean Air Status and Trends Network (CASTNet) from 1988 until 1995. Ozone data from sites in the eastern United ...States are presented and several indices are used to describe the spatial and temporal distribution of ozone concentration and exposure. These indices are SUM06, W126, the 8-hour rolling average (MAX
8hr
>80), and the current National Ambient Air Quality Standards (NAAQS) for ozone. Ozone indices were selected to illustrate the spatial and temporal distribution of ozone, and the sensitivity of this distribution to different representations of concentration or exposure.
CASTNet is unique in that a uniform set of site selection criteria and uniform procedures, including traceability to a single primary standard, provide a high degree of comparability across sites. Sites were selected to avoid undue influence from point sources, area sources, or local activities. The sites reflect a wide range of land use and terrain types including agricultural and forested, in flat, rolling, and complex terrain from the eastern seaboard across the Appalachian Mountains to the Midwest.
Results indicate that ozone concentrations varied greatly in time and space across the eastern United States. Sites in the upper northeast, upper midwest, and southern periphery subregions experienced relatively low ozone during the years of record compared to sites in the northeast, midwest, and south central subregions. Ozone exposures at an individual rural site are dependent on many factors, including terrain, meteorology, and distance from sources of precursors. Relative to the current (as of 1996) NAAQS, only a handful of CASTNet sites near major urban areas report exceedances. In contrast, the majority of CASTNet sites might exceed the proposed new primary standard for ozone.
Sites at high elevation (>900m) in the east exhibit relatively high exposure statistics (e.g., SUM06 and W126), but no exceedance of the current ozone standard from 1988 through 1995. Terrain effects explain some of the variability within subregions and are an important consideration in the design of monitoring networks for ozone and possibly other pollutants.
This paper assesses the likely effects of proposed federal programs to provide temporary subsidies to unemployed people for purchasing health insurance. A simulation model, using the Survey of Income ...and Program Participation and data from other sources, was used to quantify various effects of a typical proposal. The model illustrates how changing eligibility rules and subsidy formulas would alter the cost and other measures of program performance. If the plan were fully operational in 1998, about 1.1 million people (including insured dependents) would get at least a month of new insurance sometime during the year. The program would reduce the number of uninsured by less than half a million people.
In a comparison of different obturating techniques and materials, lateral plus vertical compaction of gutta-percha had the least coronal leakage. Using increments of gutta-percha is indicated for ...tapered canals and those with irregular anatomy.
Polar wandering in mantle convection models Richards, M. A.; Bunge, H.-P.; Ricard, Y. ...
Geophysical research letters,
15 June 1999, Letnik:
26, Številka:
12
Journal Article
Recenzirano
Odprti dostop
We calculate polar motion in models of 3‐D spherical mantle convection at Rayleigh numbers up to 108 which include internal heating, radial viscosity variations, and an endothermic phase change. ...Isoviscous models yield rapid polar motion of order 3°/Myr, but a factor of 30 increase in viscosity with depth reduces the rate of polar motion to about 0.5°/Myr due to stabilization of the large‐scale pattern of convection. Avalanching due to an endothermic phase change causes pulsating inertial interchange polar excursions of order 80–110° and of duration 20–70 Myr. A layered viscosity model with an endothermic phase change yields only one inertial interchange event in 600 million years. These models show that the slow observed rate of post‐Paleozoic true polar wander is not incompatible with higher rates inferred for earlier times.
The Clean Air Status and Trends Network (CASTNet) was implemented by the U.S. Environmental Protection Agency (EPA) in 1991 in response to Title IX of the Clean Air Amendments of 1990, which mandated ...the deployment of a national ambient air monitoring network to track progress of the implementation of emission reduction programs in terms of deposition, air quality, and changes to affected ecosystems. CASTNet evolved from the National Dry Deposition Network (NDDN). CASTNet currently consists of 45 sites in the eastern United States and 28 sites in the West. Each site measures sulfur dioxide (SO
2
), nitric acid (HNO
3
), particle sulfate (SO
4
=
), particle nitrate (NO
3
-
), and ozone. Nineteen sites collect precipitation samples. NDDN/CASTNet uses a uniform set of site-selection criteria which provides the data user with consistent measures to compare each site. These criteria also ensure that, to the extent possible, CASTNet sites are located away from local emission sources.
This paper presents an analysis of SO
2
and SO
4
=
concentration data collected from 1987 through 1996 at rural NDDN/CASTNet sites. Annual and seasonal variability is examined. Gradients of SO
2
and SO
4
=
are discussed. The variability of the atmospheric mix of SO
2
and SO
4
=
is explored spatially and seasonally. Data from CASTNet are also compared to SO
2
and SO
4
=
data from concurrent monitoring studies in rural areas.
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