Fluorescent Dye Technique Research Articles

A direct projection from the kidney to the brainstem

The double-labeling, fluorescent dye technique was used in order to demonstrate the extent to which the central processes of renal afferent neurons directly project to the brainstem. One injection of a fluorescent dye was placed in the cortex of the left kidney of male rats, and a second injection of a different dye was placed into the lower medulla. The results demonstrate that some of the renal afferents directly project to the medulla but not to higher regions of the brain. A total of approximately 8% of renal afferents were typically shown to have direct projections.

H+ Disposal by Rabbit Gastric Mucosal Surface Cells

Exposure of isolated gastric mucosal surface cells to NH4+ results in acidification of cells as determined by a fluorescent dye technique using acridine orange. The resulting intracellular pH gradient is maintained when cells are suspended in either buffered HCO3- -free Ringer's or choline chloride solution. Cells suspended in a Na+-containing but K+-free solution exhibit dissipation of the proton gradient. When Na+ is added to cells suspended in Na+, K+-free solution, the gradient rapidly dissipates with a half-maximal response occurring at 56 mM Na+. The effect of Na+ is amiloride sensitive with half-maximal inhibition occurring at 38 microM at a Na+ concentration of 50 mM. The K+ does not cause dissipation of the gradient and neither ouabain nor valinomycin have an effect. Yet, K+ has a modulating influence on Na+/H+ exchange by the isolated surface cells. The addition of K+ to acid-loaded cells resuspended in Na+-free solution decreases the ability of subsequent Na+ addition to evoke gradient dissipation. The data suggest that Na+/H+ exchange appears to be at least one mechanism whereby gastric mucosal surface cells could protect themselves against diffusing acid. This ion exchange mechanism is amiloride sensitive and appears to be unrelated to Na+, K+ adenosine triphosphatase activity, but is affected by the external K+ concentration.

A Rapid Fluorescent-dye Technique for Measuring Root Length

SummaryA fluorescent-dye technique has been developed to measure root length of field crops. Roots are washed from soil samples, stained for about 30 min in a solution of fluorescein diacetate in acetone, washed, spread out on a tension table and photographed under UV light. Lengths of fluorescent roots recorded on the photograph are estimated by line intersection. The method is quick, simple, inexpensive and largely eliminates the usual time-consuming, tedious process of hand-sorting live roots from organic debris. Whereas all the roots of young laboratory-grown plants take up the dye, some older roots of field-grown crops do not fluoresce. Data indicate that the method may also give information on root diameter.

Localization of renal sensory neurons using the fluorescent dye technique

The location of cell bodies of renal sensory neurons was studied. Small injections of a fluorescent dye (True Blue of Fast Blue) were placed into either the right or left kidney of male or female rats. Whereas no differences were detected in the labeling patterns of males vs females, right kidney injections did label slightly higher dorsal root ganglia than left injections. In all cases the labeling was confined to the T6-L2 ganglia ipsilateral to the injection.

The apical seal via the retrosurgical approach: II. An evaluation of retrofilling materials

In this investigation heat-sealed gutta-percha (A) reinforced with Adaptic (B), ASPA (C), Cupralloy without (D) and with (E) varnish, Spheraloy without (F) and with (G) varnish were used as retrofilling materials. Seventy maxillary central incisors with Class I canal anatomy were selected. Marginal leakage at the apical filling/root canal interface was evaluated quantitatively by means of a fluorescent dye technique. All statistical tests were computed at the 5 percent level of significance. Analysis of variance revealed that differences in microleakage among retrofillings were significant. Tukey's test of multiple contrasts was used to isolate statistically significant differences between all pairs of means. The following results were obtained: DFA GECB Retrofillings are ranked in descending order of microleakage. Means that are linked were not significantly different.

Laser Anemometer Measurements in a Transonic Axial Flow Compressor Rotor

A laser anemometer system employing an efficient data acquisition technique has been used to make measurements upstream, within, and downstream of the compressor rotor. A fluorescent dye technique allowed measurements within endwall boundary layers. Adjustable laser beam orientation minimized shadowed regions and enabled radial velocity measurements outside of the blade row. The flow phenomena investigated include flow variations from passage to passage, the rotor shock system, three-dimensional flows in the blade wake, and the development of the outer endwall boundary layer. Laser anemometer measurements are compared to a numerical solution of the streamfunction equations and to measurements made with conventional instrumentation.

Dog red blood cells: Na and K diffusion potentials with extracellular ATP.

External ATP causes a prompt increase in the Na and K permeability of dog red blood cells. By manipulating intra- and extracellular ion composition it is possible to observe ATP-induced net fluxes which can be explained in terms of the contribution of Na or K diffusion potentials to the membrane potential. Measurements of membrane voltage by a fluorescent dye technique confirm the existence of such potentials. A rough calculation of chloride permeability gives a value of the order of 10(-8) cm/s, which agrees with results in other species. The cells appear to be somewhat more permeable to bromide than to chloride.

A Fluorescent Dye Technique for Marking Insect Eggs in Predation Studies1

A Fluorescent Dye Technique for Marking Insect Eggs in Predation Studies1

Evidence suggesting the existence of a hypothalamic-parotid gland endocrine axis.

Evidence for the existence of a hypothalamic-parotid endocrine axis was demonstrated with a fluorescent dye technique. The intraperitoneal injection of the dye, acriflavine hydrochloride, provided a simple method to study the movement of fluid through the odontoblastic tubules in the dentine of rat molars. Hypothalamic extract (HE) injected iv into intact rats stimulated the movement of fluid through the odontoblastic tubules in the dentine. Extracts of other tissues and antidiuretic hormone failed to duplicate the effect observed with HE. Fluid movement was not obtained in sialoadenectomized rats. Fluid movement was obtained only when the HE was administered to rats with intact parotid glands or when parotid tissue extract was given iv to parotidectomized rats. These results suggest that the hormonal stimulation of fluid movement through the odontoblastic tubules is directly dependent upon the parotid. Fluid movement was obtained in hypophysectomized rats, which indicated that the hypothalamic factor act...

Fluorescent Dye Technique for Studying Distribution of Spray Oil Deposit on Citrus1

An oil soluble fluorescent dye was incorporated with various petroleum oils to provide a qualitative means of studying the relative deposit of the dilute oil spray mistures on various parts of grapefruit trees on exposure under ultraviolet light. This technique provided a good means of qualitative comparisons of differences in oil deposit associated with (1) the concentration of oil in the spray mixture, (2) various surfactants and (3) concentration of surfactant. The dye penetrated with the oil into the outer mesocarp of the green fruit with applications during July while less penetration was observed from those made during August. Only surface deposit appeared to have occurred on mature grapefruit held in storage from the 1959 crop. The dye penetrated into the bark of green twigs but appeared to have been deposited only on the surface of the bark of small branches. The dye appeared to have penetrated into the leaf mainly at the midrib and larger veins. Photegraphs of petroleum oil deposit on the fruit, leaves, and twigs and small branches are included.

The critical range for micelle formation by an oil-dispersible soap in a hydrocarbon solvent

Micelle formation by the oil-dispersible soap, calcium xenylstearate, in moist benzene has been studied by fluorescent dye techniques, utilizing Rhodamine B and Acridine Orange. A treatment is presented for the interpretation of fluorescence depolarization data obtained from a system in which the emitting dye is present partly as a component of soap micelles and partly in true molecular solution. This method has special usefulness for identifying the onset of micelle formation in very dilute solutions. The midpoint of the critical range for the formation of micelles in this case is found to be 0.6 × 10 −6 mole/l.; the size of the micelles is essentially constant over the range from 1 × 10 −6 to 7 × 10 −3 mole/l. The data obtained are consistent with a simple mass law equilibrium between molecularly dissolved and micellar soap. A knowledge of this equilibrium provides guidance in the development of improved rust-inhibiting oils.

Detection of Soil Removal in Metal Cleaning by the Radioactive Tracer Technique

The sensitivity of various methods for the determination of surface cleanliness is known in but few instances. The radioactive tracer technique as a quantitative method is used to define the apparent limits of sensitivity of the water break, fluorescent dye, and copper plate methods.The methods in increasing order of sensitivity are: fluorescent dye, copper plate, water break, and radioactive tracer technique. Quantitative estimates of limits of sensitivity are given.