Short-Term Collecting Method

Although the most accurate way to estimate the characteristics of natural hormone transport is in a system as intact as possible, the method outlined below has not been adopted to any great extent. 

In studies of the basipetal auxin transport in flower stalks of Fritillaria, a method has been used which may be likely to estimate the in situ situation (Kaldewey 1968 b, 1971). The basic idea of this method was to replace the stream of endogenous auxin, delivered to the stalks by the bud or fruit (Kal- 

DEWEY 1957, 1964), with radioactive lAA and to follow its behavior in the plant, left as intact as possible. The natural auxin source was replaced by a lanolin paste containing lAA (in this case, C-IAA). The new auxin source sustained natural elongation and growth movements of the stalk (Kaldewey 1957, 1962, 1965b). Seven hours later, the axis of the plant was cut several centimeters below the apex and supplied at the cut end of its base with agar receivers, twice each for 15-min periods. Then, a 5-mm section was excised and stood on fresh agar receivers to allow all the mobile auxin to move out, and the new basal cut surface of the remaining axis was successively supplied with another pair of receivers for 15-min periods. The radioactivity collected in the 15-min receivers and the section receivers, respectively, allowed an estimation of the transport intensity and transport density. It was possible, therefore, to calculate the transport velocity from these quantities [see Eq. (2)]. Further, auxin immobilized within the 5-mm sections could be determined by extraction (see Fig. 3.6). 

Similar conclusions have been drawn from studies of C-IAA transport in Pisum internodes (Kaldewey et al. 1974) and Citrullus hypocotyls (Kaldewey et al. 1977), as affected by water stress and transport inhibitors, respectively. Water stress, as well as the inhibitor lycoricidinol, drastically decreased the transport density, as estimated by the intercept method, although the total amount of mobile auxin emerging ftom the basal cut surfaces of subsections after transport periods of 4 to 5 h increased or was only slightly decreased. Further, both treatments caused a higher portion of total 

3 Transport and Other Modes of Movement of Hormones (Mainly Auxins) 

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These results suggest that in the short-term collection method basal and apical receivers should be applied simultaneously. By this means, the acropetal component of the transport system is accounted for and the auxin then delivered to basal receivers probably will give a more accurate measure for the density of the basipetal auxin stream. Moreover, the calculation of the acropetal/basipetal ratio may reflect the polarity of hormone translocation. 

Fig. 3.6. Transport and distribution of radioactivity originating from 2- C-IAA, applied to decapitated apices of geoepinastically bent flower stalks of Fritillaria meleagris L. The transport characteristics have been evaluated by the short-term collecting method (see Sect. 3.3.2.2). The transport intensity was calculated from the radioactivity collected in agar receivers applied for two 15-min periods to the basal cut surface of a 5-cm explant, continuously supplied with an auxin paste source. The cut was separated by a mica plate into upper and lower halves or the convex and concave sides of the bent axis. After the second collection period, a 5-mm section was excised and radioactivity similarly collected from the new cut surface, and so forth up to the apex. The excised 5-mm sections were separated in upper and lower halves and placed individually on agar receivers for 1 h, to determine the transport densities. They were then exhaustively extracted with ethanol to give the immobilized fractions. (Mean values of four plants, data from Kaldewey 1968 b)...

Haas M, Kluppel AC, Moolenaar F et al. (1997) Urine collection in the freely-moving rat reliability for measurement of short-term renal effects. J Pharm Tox Methods 38 47-51 Loeb WF (1998) The measurement of renal injury. Toxicol Pathol 26 26-28... 

Urinary corticoid measurements (in 17-24 h, but not short-term samples) can be used to assess adrenocortical function as alternatives to blood sampling techniques (Hilfenhaus 1977). The use of urinary measurements over a timed period may provide a better indication of corticosteroid metabolism in contrast to the fluctuations observed in plasma measurements. Although some reports in the literature use randomly collected urine for veterinary clinical diagnosis, these measurements are not suitable for toxicological studies. Older methods for urinary 17-hydroxycorticoster-oids have been replaced by cortisol or corticosterone measurements. 

Special studies such as randomised control clinical trials or observational studies can be used to gather data that are not collected by routine monitoring systems these however involve additional costs and it may prove very difficult to maintain them consistently over a long period. Sentinel reporting systems, which collect data on a carefully selected sample, are useful for monitoring the short-term impact of policy implementation, particularly in order to detect unexpected or unintended outcomes [18]. Time pressures, the availability of financial resources and the willingness of staff members to comply with requirements will influence the type of monitoring method selected. 

Soil can accumulate radionuclides over long time periods but may not be useful for observing short-term trends. Measurements can provide retrospective information on radionuclide levels. Site description, location, collection date and time, sample area and depth, and sampling method (core, template, trench) should be recorded along with the sample identification number and name of sample collector. 

Hyperuricosuria was defined as urate excretion exceeding the mean plus one standard deviation found in healthy subjects, which corresponds to 4.0 and 4.5 mmol/24 hours for females and males respectively. So defined, hyperuricosuria was found in 57 subjects. These 57 patients were compared with an age- and sex-matched group of stone formers who had normal excretion of urate. All patients were investigated ambulatorily on their ordinary diet. Urate was measured with an enzymatic spectrophotometric method. Lithium carbonate (LiCOa) was used as a preservative for urinary collections. Renal acidification capacity was investigated with a short-term ammonium chloride load (5). 

The first right-hand term collects steric, or repulsion, short-range interactions, the second the electrostatic ones, and the third those collectively known as dispersion interactions. This partition allows us to use the so-called coupling parameter method (or charging method ) with a partition of the coupling parameter into components with a real physical meaning. 

An EPA report "Disposal of Dilute Pesticide Solutions" ( ) summarized technologies used In disposal of such wastes. Another study entitled "Economic Analysis of Pesticide Disposal Methods" (j4) evaluated commonly used disposal systems In terms of cost. Local, regional and statewide collection and disposal strategies were also considered. Although each of these reports contain valuable Information, they fall short of the target of providing adequate Information to pesticide regulators and users to draw upon In day-today operations. 

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