Intravascular catheters-an ultrasound imaging based observational study of position and function.

Peripheral intravenous and intra-arterial catheters often block with movement of the limb in which they are inserted. Although the cause of this blockage is commonly attributed to a valve or other structure within the vein, evidence for this is lacking. We used ultrasound to assess the cause of blockage on movement, and degree of tip movement, of 62 venous and 21 radial arterial catheters. In both venous and arterial catheters, blockage was predominantly caused by impingement of the catheter on the vessel wall, with catheter kinking and spasm of the vessel also seen. Mean potential tip movement was 12.3 mm and 5.7 mm in hand and forearm venous catheters respectively and 9.5 mm in radial artery catheters. There was a significantly lower rate of blockage for forearm (20%) compared to dorsal hand venous catheters (83%, P <0.001) and 52% of radial artery catheters showed damping and blockage on wrist flexion. This study emphasises the advantages of placement of venous catheters in the straight veins of the forearm.

Predicting stored grain insect population densities using an electronic probe trap.

Manual sampling of insects in stored grain is a laborious and time-consuming process. Automation of grain sampling should help to increase the adoption of stored grain integrated pest management. A new commercial electronic grain probe trap (OPI Insector) has recently been marketed. We field tested OPI Insector electronic grain probes in two bins, each containing 32.6 tonnes of wheat, Triticum aestivum L., over a 2-yr period. We developed new statistical models to convert Insector catch into insects per kilogram. We compared grain sample estimates of insect density (insects per kilogram of wheat) taken near each Insector to the model-predicted insect density by using Insector counts. An existing expert system, Stored Grain Advisor Pro, was modified to automatically read the Insector database and use the appropriate model to estimate Cryptolestes ferrugineus (Stephens), Rhyzopertha dominica (F.), and Tribolium castaneum (Herbst) density from trap catch counts. Management decisions using Insector trap-catch estimates for insect density were similar to those made using grain sample estimates of insect density for most sampling dates. However, because of the similarity in size of R. dominica and T. castaneum, the software was unable to differentiate counts between these two species. In the central and southern portions of the United States, where both species frequently occur, it may be necessary to determine the proportion of each species present in the grain by manual inspection of trap catch. The combination of SGA Pro with the OPI Insector system should prove to be a useful tool for automatic monitoring of insect pests in stored grain.

Sampling plans for the psocids Liposcelis entomophila and Liposcelis decolor (Psocoptera: Liposcelididae) in steel bins containing wheat.

Psocids are an emerging problem in grain storage, handling, and processing facilities in the United States. We used data from two steel bins each containing 32.6 metric tonnes of wheat, Triticum aestivum L., to develop sampling plans for Liposcelis entomophila (Enderlein), Liposcelis decolor (Pearman) (both Psocoptera: Liposcelididae), and a mixture of the two species. Taylor's coefficients a (a sampling factor) and b (an index of aggregation) for these pests were calculated and incorporated into sampling protocols to improve accuracy. The optimal binomial sample sizes for estimating populations of these psocids at densities of < 25 psocids per refuge were large; therefore, we recommend the use of numerical sampling within this range of densities. Numerical sampling of L. entomophila and L. decolor at densities of < 25 psocids per refuge should not be too laborious given the low psocid numbers involved; we recommend using 10 refuges per bin. For presence-absence sampling of L. entomophila or L. decolor, 20 refuges per bin should be used at densities of 25-100 psocids per refuge. The sampling plans we have developed based on the use of cardboard refuges are convenient for use in steel bins containing wheat because they are inexpensive, provide a rapid assessment of psocid population incidence, and are easy to implement. These sampling plans can be used to monitor populations of and the efficacy of management strategies used against L. entomophila and L. decolor.

Temporospatial distribution of the psocids Liposcelis entomophila and L. decolor (Psocoptera: Liposcelididae) in steel bins containing wheat.

We studied the temporospatial distribution of psocids in steel bins containing 32.6 tonnes of wheat in 2005 and 2006 in Manhattan, KS. Psocids were sampled in the top 0.9 m of wheat using a 1.2-m open-ended trier; samples were taken from the bin center and in the four cardinal directions at 0.15 and 0.76 m from the bin wall. In addition, a 2.4-m partitioned grain trier with 16 compartments was used to sample psocids from a 2-m-diameter circle in the center of the bins and to a depth of 1.96 m. Only two species of psocids were identified in the study: Liposcelis entomophila in 2005 and L. decolor in 2006. Densities of psocids were low immediately after bins were filled in July 2005, peaked in October, dropped to almost zero in December as temperatures decreased, and remained at low levels until the study was ended in March. In 2006, densities of psocids increased gradually from August to mid-October and declined until the study was ended in early November. During the fall, psocids were more abundant at the center of the bin and at lower depths. In October to November of both years, the temperatures and moisture contents of grain in the center also were higher than that in other locations. This is the first report of temporospatial distribution of psocids in steel bins of wheat.

Evaluation of five sampling methods for the psocids Liposcelis entomophila and L. decolor (Psocoptera: Liposcelididae) in steel bins containing wheat.

An evaluation of five sampling methods for studying psocid population levels was conducted in two steel bins containing 32.6 tonnes of wheat in Manhattan, KS. Psocids were sampled using a 1.2-m open-ended trier, corrugated cardboard refuges placed on the underside of the bin hatch or the surface of the grain, and manual or automated electronic counts from Insector probe traps. Only two species were identified in this study: Liposcelis entomophila (Enderlein) in 2005 and L. decolor (Pearman) in 2006. In both years, psocid numbers started to increase in early September, peaked earliest in surface refuges, and peaked at nearly the same time in grain samples and manual and electronic Insector counts. No psocids were found in hatch refuges in December to February, although psocids were detected by the other sampling methods during this time. Numbers of psocids in the grain samples could be estimated from the numbers of psocids obtained using the cardboard refuges and Insector probe traps in both years. The results indicate that cardboard refuges or Insectors may provide an effective method for sampling psocids in bins of wheat.

Comparison of aeration and spinosad for suppressing insects in stored wheat.

Field studies were conducted from July 2002 to January 2003 for evaluating the effects of controlled aeration and a commercial biological insecticide, spinosad, in suppressing insect populations in stored wheat. Six cylindrical steel bins were filled with newly harvested (2002 crop year) hard red winter wheat on 9 and 10 July 2002. Each bin contained 30.7 metric tons (1,100 bu) of wheat. Wheat in two bins was left untreated (control), whereas wheat in two bins was treated with spinosad, and in another two bins was subjected to aeration by using aeration controllers. Spinosad was applied to wheat at the time of bin filling to obtain a rate of 1 mg ([AI])/kg. Aeration controllers were set to run the fans when ambient air temperature fell below 23.9, 18.3, and 7.2 degrees C for the first, second, and third cooling cycles, respectively. We added 400 adults each of the rusty grain beetle, Cryptolestes ferrugineus (Stephens); lesser grain borer, Rhyzopertha dominica (F.); and red flour beetle, Tribolium castaneum (Herbst), to the grain at monthly intervals between July and October 2002. Insect density in the bins was estimated monthly by taking 3-kg grain samples from 21 locations within each bin by using a pneumatic grain sampler. No live T. castaneum or C. ferrugineus and very low densities of R. dominica (<0.008 adults per kilogram) were found in wheat treated with spinosad during the 6-mo sampling period. Density of C. ferrugineus and T. castaneum in aerated bins did not exceed two adults per kilogram (the Federal Grain Inspection Service standard for infested wheat), whereas R. dominica increased to 12 adults per kilogram in November 2002, which subsequently decreased to three adults per kilogram in January 2003. In the untreated (control) bins, R. dominica density increased faster than that of C. ferrugineus or T. castaneum. Density of R. dominica peaked at 58 adults per kilogram in October 2002 and decreased subsequently, whereas T. castaneum density was 10 adults per kilogram in October 2002 but increased to 78 adults per kilogram in January 2003. Density of C. ferrugineus increased steadily during the 6-mo study period and was highest (six adults per kilogram) in January 2003. This is the first report comparing the field efficacy of spinosad and aeration in managing insects in farm bins. Our results suggest that spinosad is very effective in suppressing R. dominica, C. ferrugineus, and T. castaneum populations in stored wheat.

Wheat in bins and discharge spouts, and grain residues on floors of empty bins in concrete grain elevators as habitats for stored-grain beetles and their natural enemies.

Wheat stored in upright concrete bins at seven grain elevators in central Kansas was sampled intermittently for insects over a 2.5-yr period by collecting samples from the upper half of the grain mass, from the discharge spout at the base of the bins, and from residue remaining in empty bins before the 2000 wheat harvest. Samples were taken from the grain mass with a power vacuum sampler (PV) and from the discharge spouts (DS) by dropping grain onto the reclaim belt beneath the bins. The density and species distribution in the residue samples were compared with those found in the DS samples and samples from the grain mass (PV). Cryptolestes spp. dominated the insect populations in all types of samples, constituting >40% of all insects in the PV samples in three of five time periods and >60% of all insects in DS samples in four of the five time periods. Cryptolestes spp. was an early colonizer, being found in the grain mass shortly after new grain was added. Rhyzopertha dominica appeared to be slower to colonize grain and grain residue, but sometimes developed large populations (i.e., 2.4 +/- 0.7 adults/kg between July and December 2000). Sitophilus spp. weevils often were present in grain masses, were often abundant in grain in the discharge spouts (i.e., 11.1 +/- 2.9 adults/kg between July and December 2000), and were abundant in grain residue in empty bins in May/June 2000 (5.3 +/- 0.7 adults/kg). Differences in density and species distribution of insects in grain in the upper part of the grain mass and those in the discharge spouts indicated that the populations were not closely related. Grain in discharge spouts usually was densely infested, and parasitic wasps, natural enemies of several of the beetles, were found when the density of the pest insects was greater than approximately 10/kg. The population of natural enemies appeared to increase when the density of pest insects increased after a lag of about one month, and decreased when the population of pest insects decreased. Grain in discharge spouts appeared to provide an incubation chamber for pest insects, and removing this grain periodically should reduce the resident populations. Residue in empty bins often was densely infested compared with samples from the grain masses. Cleaning the empty bins before refilling with newly-harvested wheat resulted in a significantly-reduced density of pest insects in discharge spouts later, and the effect lasted at least 12 wk after filling.

Aeration management for stored hard red winter wheat: simulated impact on rusty grain beetle (Coleoptera: Cucujidae) populations.

Simulation studies were conducted to determine temperature accumulations below defined thresholds and to show the impact of controlled aeration on populations of the rusty grain beetle, Cryptolestes ferrigineus (Stephens), a major secondary pest of stored wheat, Triticum aestivum (L.). Recorded data from weather stations in Texas, Oklahoma, Kansas, eastern New Mexico, and eastern Colorado (356 total) were used to determine hours of temperature accumulation below 23.9 degrees C in June and July, 15.6 degrees C in September and October, and 7.2 degrees C in December. At an airflow rate of 0.0013 m3/s/m3 (0.1 cubic ft3/min/bu), which requires 120 h of temperatures below the specified threshold to complete an aeration cycle, summer cooling at 23.9 degrees C in bulk-stored wheat could be completed throughout the hard red winter wheat zone except for extreme southern Texas. An early-autumn cooling cycle at 15.6 degrees C could not be completed throughout most of Texas and Oklahoma before the end of September. The late-autumn cooling cycle could be completed in all states except Texas by the end of November. Five geographic regions were delineated and the times required for completion of the summer, early-autumn, and late-autumn cooling cycles within each region were estimated. Population growth of the rusty grain beetle was modeled for San Antonio, TX; Abilene, TX; Tulsa, OK; Topeka KS; and Goodland, KS, by predicting the numbers of adults in the top, outer middle, outer periphery, and the center of the bin during a 1-yr storage season. Populations of C. ferrugineus in San Antonio and Austin were predicted to exceed the Federal Grain Inspection Service (FGIS) threshold of two beetles per kilogram of wheat in all four levels of the bin during late autumn, decline during the winter, and increase the following spring. In Midland, TX, and Oklahoma City, OK, populations were predicted to exceed the threshold only in the top and outer middle of the bin, whereas populations in the Kansas locations were not predicted to exceed the threshold at any time.

Nerve growth factor attenuates cholinergic deficits following traumatic brain injury in rats.

Traumatic brain injury (TBI) results in chronic derangements in central cholinergic neurotransmission that may contribute to posttraumatic memory deficits. Intraventricular cannula (IVC) nerve growth factor (NGF) infusion can reduce axotomy-induced spatial memory deficits and morphologic changes observed in medial septal cholinergic neurons immunostained for choline acetyltransferase (ChAT). We examined the efficacy of NGF to (1) ameliorate reduced posttraumatic spatial memory performance, (2) release of hippocampal acetylcholine (ACh), and (3) ChAT immunoreactivity in the rat medial septum. Rats (n = 36) were trained prior to TBI on the functional tasks and retested on Days 1-5 (motor) and on Day 7 (memory retention). Immediately following injury, an IVC and osmotic pump were implanted, and NGF or vehicle was infused for 7 days. While there were no differences in motor performance, the NGF-treated group had significantly better spatial memory retention (P < 0.05) than the vehicle-treated group. The IVC cannula was then removed on Day 7, and a microdialysis probe was placed into the dorsal hippocampus. After a 22-h equilibration period, samples were collected prior to and after administration of scopolamine (1 mg/kg), which evoked ACh release by blocking autoreceptors. The posttraumatic reduction in scopolamine-evoked ACh release was completely reversed with NGF. Injury produced a bilateral reduction in the number and cross-sectional area of ChAT immunopositive medial septal neurons that was reversed by NGF treatment. These data suggest that cognitive but not motor deficits following TBI are, in part, mediated by chronic deficits in cholinergic systems that can be modulated by neurotrophic factors such as NGF.

Rapid screening of pharmaceuticals by thin-layer chromatography: analysis of essential drugs by visual methods.

A method for rapidly screening pharmaceuticals by thin-layer chromatography has been designed for use in areas with limited resources and by operators with limited training. An apparatus for performing the analysis in a plastic bag under equilibrium conditions was designed. Results can be reproduced by different operators and in different locations. The analysis can be performed without electricity or in a remote area, away from a laboratory. It is especially suited for field use in developing countries. The method is low cost, maintenance-free, fast, and reliable; it also uses limited volumes of solvents. The analyses can be performed without weighing if reference materials can be supplied in tablet form, provided the drug content is listed and only one unit is required for each analysis. All procedures were developed for the analysis of drugs from a partial list of essential drugs established by the World Health Organization. Three drugs were selected and prepared in the form of reference tablets. Comparisons with the analyses of the drugs in standard dosage forms were made by using reference tablets and primary USP standards. Comparable results were obtained, proving that the screening process can be conducted by using reference tablets and without weighing either the sample or the reference. The method has been successfully demonstrated and used in Swaziland, by high school teachers in the United States, and by personnel from the Ministry of Health in Saudi Arabia. Personnel can be trained in a short time to perform screening analysis of drugs.

A simple, inexpensive thin-layer chromatography method for the analysis of theophylline tablets.

A simple, low-cost thin-layer chromatography (TLC) procedure to estimate the quality of simple pharmaceuticals in tablet form is described together with easily built equipment to carry out the test in the field. The approach is demonstrated for theophylline, but can be used to assay the drug content of any tablet or to determine its dissolution or disintegration characteristics. The procedure can be used in the field without the need for any instrumentation.

A simple, inexpensive thin-layer chromatography method for the analysis of theophylline tablets

A simple, low-cost thin-layer chromatography (TLC) procedure to estimate the quality of simple pharmaceuticals in tablet form is described together with easily built equipment to carry out the test in field. The approach is demonstrated for theophylline, but can be used to assay the drug content of any tablet or to determine its dissolution or disintegration characteristics. The procedure can be used in the field without the need for any instrumentation(AU)

Aspirin--a national survey V: Determination of aspirin and impurities in enteric coated tablets and suppository formulations and in vitro dissolution of enteric coated tablets.

The results of a national survey on the quality of enteric coated aspirin tablets and aspirin suppositories are presented. The tablets were analyzed for strength, salicylic acid content, in vitro dissolution rate, and related aspirin impurities. The suppositories were analyzed for strength and salicylic acid content. The methods of analysis and validation of data are also presented.

Quantitative TLC determination of epimeric ratios of 16-methyl 17-ketone oxidation products of dexamethasone and related drugs.

A TLC system sensitive enough to detect, identify, and allow quantitation of the 16-methyl alpha- and beta-epimers of 9-fluoro-11 beta-hydroxy-16-methylandrosta-1,4-diene-3,17-dione is described. These epimeric 17-ketones may be present as impurities in dexamethasone, betamethasone, or related drugs. A spectrodensitometer with a TLC scanning attachment was used, and results from densitometry compared favorably with quantitation by high-performance liquid chromatography, as was described recently. TLC was convenient in the rapid examination of drug samples for the detection and identification of epimeric 17-ketones and for the determination of the alpha to beta ratio of such epimers. Various applied photographic techniques for documenting TLC data are described.

Preparation of superior thin-layer chromatograms for quantitative in situ densitometry by nonequilibrated development. I. Trisulfapyrimidines: sulfadiazine, sulfamerazine, and sulfamethazine.

A method of obtaining controlled nonequilibrated horizontal plate development by employing a developing system open to room atmosphere is described and compared with other plate-developing techniques. Nonequilibrated plate development produced spot configurations with the precise physical outline and densitometric distribution needed for optical scanning.

Stability study of nitroglycerin sublingual tablets.

Nitroglycerin sublingual tablets were studied over a 1-year period to determine tablet stability in terms of loss of strength, uniformity of tablets, and degradation of the drug itself. Tablets from six different firms were analyzed by a semiautomated procedure. The samples included two molded tablets and four compressed tablets, ranging in age at the time of initial assay from 40 days to over 1 year. The results indicated that there is a loss of strength of nitroglycerin tablets and that refrigeration slows down this loss. The study also indicated that these tablets were stable during the year of testing in terms of tablet uniformity and degradation of nitroglycerin.