RESUMEN
A common method for identifying collateral projections is to inject different retrograde tracers into two targets and examine labeled cells for the presence of both tracers. Double-labeled cells are considered to have collateral projections to the two injection sites. This method is widely considered to underestimate the extent of collaterals. To test the efficiency of double-labeling, we mixed equal volumes of two tracers, injected them into one site in a guinea-pig brain, and counted the resulting labeled cells. Ideally, the tracers would have precisely overlapping injection sites and all labeled cells would contain both tracers. We tested several combinations of tracers: 1) Fast Blue and fluorescein dextran; 2) fluorescein dextran and FluoroGold; 3) fluorescein dextran and FluoroRuby; 4) FluoroGold and green beads; 5) FluoroGold and red beads; 6) FluoroRuby and green beads; and, 7) green beads and red beads. For each combination, a mixture was injected into the left inferior colliculus. After 1 week to allow for transport, labeled cells were counted in the right inferior colliculus and the left temporal cortex. For each mixture, the results were similar for the two areas. The percentage of cells that were double-labeled varied from 0% to 100%, depending on tracer combination. The highest efficiencies (>96%) were observed with red beads and green beads or with FluoroRuby and fluorescein dextran. The limited efficiency of other mixtures could be accounted for only in part by incomplete overlap of the two tracers at the injection site. The results indicate that the specific combination of tracers used to search for collateral projections can greatly affect the findings.
Asunto(s)
Axones/fisiología , Encéfalo/anatomía & histología , Vías Nerviosas/anatomía & histología , Amidinas , Animales , Axones/metabolismo , Mapeo Encefálico , Colorantes/administración & dosificación , Colorantes/metabolismo , Dextranos/administración & dosificación , Dextranos/metabolismo , Femenino , Fluoresceínas/administración & dosificación , Fluoresceínas/metabolismo , Cobayas , Indicadores y Reactivos/administración & dosificación , Masculino , Vías Nerviosas/metabolismoRESUMEN
Seven kairomone formulations (Trécé, Inc., Salinas, CA) were evaluated for their effectiveness as attractants for luring three species of cucumber beetles into Pherocon CRW traps (Trécé, Inc.) in cucurbit and sweetpotato fields. The spotted cucumber beetle, Diabrotica undecimpunctata howardi Barber; the banded cucumber beetle, Diabrotica balteata LeConte; and the striped cucumber beetle, Acalymma vittatum (F.), were captured in this study. TRE8276 (TIC mixture: 500 mg of 1,2,4-trimethoxybenzene, 500 mg of indole, and 500 mg of trans-cinnamaldeyde) and TRE8336 (500 mg of 1,2,4-trimethoxybenzene, 500 mg of trans-cinnamaldeyde, 500 mg of 4-methoxyphenethanol) were the most effective lures for spotted and striped cucumber beetles. None of the kairomone lures was very effective for attracting banded cucumber beetles. Three population peaks of spotted cucumber beetles were observed in cucurbit and sweetpotato fields at the U.S. Vegetable Laboratory (Charleston, SC). The efficacy of TRE8276 declined rapidly after 2 wk in the field. An improved design of the Pherocon CRW trap, with a yellow bottom and more-tapered top section, was more effective for capturing cucumber beetles than the original trap design made entirely of clear plastic. Banded cucumber beetles were not captured in sweetpotato fields at inland locations in North Carolina or South Carolina.
Asunto(s)
Escarabajos , Cucurbitaceae , Control de Insectos/métodos , Ipomoea batatas , Feromonas , Animales , Control de Insectos/instrumentación , Densidad de PoblaciónRESUMEN
A 64-year-old man presented with jaundice. Hepatobiliary imaging using 99mTc-DISIDA revealed complete hepatobiliary tract obstruction with a photopenic area corresponding to a dilated gallbladder and a large photopenic region corresponding to a distended stomach as a result of gastric outlet obstruction. At surgery, carcinoma of the head of the pancreas was found to be the cause of the combined common bile duct and gastric outlet obstruction.