Salivary tears resulting from SMG-transplantation represent condensed SMG saliva. Thus their quality is intermediate between normal tears and normal SMG saliva. High levels of secretory proteins demonstrate that the gland maintains an active function. Surgical denervation and residual tear components from the ocular surface are the most likely factors to cause the complex differences between normal SMG saliva and SMG-salivary tears. The effects of this secretion on the ocular surface are currently being evaluated in a clinical and laboratory study.

Salivary tears resulting from SMG-transplantation represent condensed SMG saliva. Thus their quality is intermediate between normal tears and normal SMG saliva. High levels of secretory proteins demonstrate that the gland maintains an active function. Surgical denervation and residual tear components from the ocular surface are the most likely factors to cause the complex differences between normal SMG saliva and SMG-salivary tears. The effects of this secretion on the ocular surface are currently being evaluated in a clinical and laboratory study.

Qualitative assays are sometimes used as the sole basis for detecting drug residues in live animals or in animal products. Such assays have become increasingly sensitive as detection technologies have improved, yet the limitations of such assays to discriminate purposeful and accidental drug exposures remain poorly defined. A study was conducted to determine the ability of a ractopamine lateral flow assay to accurately detect incurred ractopamine residues in contaminated feeds and in sheep fed trace quantities of ractopamine HCl. False positive and negative samples were determined using a quantitative liquid chromatography-tandem mass spectrometric (LC-MS/MS) method. Ractopamine HCl was fed to sheep at 0 (Zero), 1 (Low), 10 (Med), or 100 (High) µg/kg of diet ( = 4 per level, 0.5 kg of feed/d) for 7 consecutive d and urine was collected daily about ∼16 h post exposure. On-site lateral flow assays were able to reliably (0% false negatives) detect 20 μg of ractopamine HCl per kg of feed. Urine from treated sheep tested positive for ractopamine residues by lateral flow assay in 7.4 (Zero), 0 (Low), 82 (Med), and 86% (High) of the urine samples from each group. Parent ractopamine was below the assay limit of quantification (LOQ, 0.7 ng/mL) in all urine samples using LC-MS/MS. After hydrolysis of ractopamine conjugates, total ractopamine (parent + hydrolyzed metabolites) in urine of Low animals was always less than the LOQ, but in 7 of 28 samples were above the limit of detection (LOD, 0.22 ng/mL). In contrast, urine in Med animals contained 1.08 to 9.13 ng/mL of total ractopamine, while urine of High animals contained 4.85-32.82 ng/mL of total ractopamine. Ractopamine is rapidly eliminated; nevertheless, > 80% of urine samples from sheep exposed to 5 µg/d (M) of ractopamine HCl had detectable residues by the screening assay and a 100% of samples had measurable ractopamine using LC-MS/MS methods. Tissue residues of ractopamine were not detected in any of the sheep. The sensitivity with which the rapid, qualitative assay detected ractopamine was sufficient to reveal trace ractopamine exposures; these data suggest that the use of qualitative tests to indicate purposeful treatment of animals (i.e., for doping or growth enhancement), in the absence of collaborating quantitative data, is inappropriate.

No abstract

Prescreening of urine specimens by teststrips is a valuable procedure for reducing the work load of the urine analysis iaboratory: positive results for leukocytes, erythrocytes (haemoglobin), protein, and/or nitrite are widely used to select pathological specimens for subsequent microscopic examination. By standardization of the measurement conditions, mechanized teststrip reading is claimed to give more reproducible results than conventional techniques. To assess their ability to improve urine prescreening, especially with regard to the comparability of the results, the practical and analytical performance of three commercially available analysers (Rapimat® II/T from Behringwerke AG, Urotron® RL9 from Boehringer Mannheim GmbH, and Clinitek® 200 from Ames/Bayer Diagnostic) was compared with visual reading. Analytical criteria were assessed using routine urine samples, while reproducibility was tested by repeated analysis of three different commercial control urines (Kova®Trol from Madaus). A mean imprecision between 3% and 11.9% was found for the mechanized dipstick reading which was comparable to that found with visual examination (4.5% with Combur 9 -teststrips, Boehringer Mannheim GmbH). Due to the crude classification of the results, the different analysers äs well äs the visual technique gave quite different distributions for each of the semiquantitative parameters in the same urine samples. Even if statistical analysis was restricted to the frequency of positive results oniy, significant differences (% 2 -test, p < 0.001-0.05) between methods were obtained, but these differences could not be attributed to one method alone. Using microscopic Sediment analysis äs reference, pathological urines were detected with a comparable sensitivity/specificity: Urotron 0.85/0.84, Rapimat 0.91/0.67, Clinitek 0.82/0.81, and duplicate visual reading 0.88/0.67 and 0.91/0.93. Mechanized teststrip reading had no obvious advantage with respect to the time required. We conclude:(i) no improvernent in analytical performance or in speed of analysis could be claimed for mechanized methods in comparison with visual reading;(ii) mechanized teststrip reading might decrease the work load of the urine Iaboratory if integrated into a computerized laboratory System;(iii) mechanized teststrip reading will become analytically advantageous over visual reading if a more refined classification of the results is achieved. troduction^ mechanized teststrip reading have been developed Pre-screening of urine specimens by teststrips is a which are considered to have several advantages in valuable tool for reducing the work load in the urine relation to visual inspection. For example, they are analysis laboratory (l, 2). Positive results for leuko-claimed to give more reproducible results by standcytes, erythrocytes, protein and/or nitrite are widely ardized incubation and measurement conditions. Inused to select pathological samples for microscopic cluding multi-centre evaluation, the reliability of the examination (3 -6). In the last years various ...