Polyethylene Glycol Test Research Articles

Evaluation of polyethylene glycol precipitation as screening test for macroprolactinemia using Architect immunoanalyser

We performed the polyethylene glycol (PEG) precipitation test to determine the prevalence of macroprolactinemia in 172 hyperprolactinemic subjects with prolactin (PRL) levels > 700 mIU/l. PRL was measured by Architect i2000 (Abbott Diagnostics) both in serum and in supernatant obtained after PEG. We used the PRL recovery percentage ( R%) as interpretative criterion of PEG test and we estimated a prevalence of macroprolactinemia of 21.5% ( R% ≤ 40%), whereas 74.4% of subjects showed a true hyperprolactinemia ( R% ≥ 60%). In true hyperprolactinemic subjects PRL levels obtained before and after PEG showed a good correlation (Pearson coefficient, R = 0.995); in macroprolactinemic individuals no correlation was found. The PEG test was also performed in 50 normoprolactinemic subjects and a new PRL reference interval was obtained: 64–453 mIU/l. In this case the macroprolactinemic subjects (hyperprolactinemic presenting a normal PRL value after PEG) were 20.3% whereas 79.7% showed still elevated PRL levels. In 35 females we were also able to evaluate the symptoms and the pituitary imaging findings: no significant differences between macroprolactinemic ( N = 11) and true hyperprolactinemic ( N = 24) subjects were found. In conclusion, the PEG test appears to be simple, reproducible and absolutely necessary for diagnostics of hyperprolactinemia.

Leaf Water Relations, Osmotic Adjustment, Cell Membrane Stability, Epicuticular Wax Load and Growth as Affected by Increasing Water Deficits in Sorghum

A neto experiment was conducted witn a non-irrigated water stress treatment and an irrigated control using tour sorgnum {Sorghum bicolor L. Moench) cultivars. We investigated the effects of water deficits on leaf water relations, osmotic adjustment, stomatal conductance, cuticular conductance, cell membrane stability (CMS) measured by the polyethylene glycol (PEG) test, epicuticular wax load (EWL), cytoplasmic lipid content, solute concentration in cell sap, and growth. Osmotic adjustment was observed under water deficit conditions. Lower osmotic potential enabled plants to maintain turgor and decreased the sensitivity of turgor-dependent processes. Sugar and K were identified as the major solutes contributing to osmotic potential in sorghum. Sugar and K concentrations in cell sap increased by 37-4% and 27%, respectively, under water deficit conditions in favour of decreasing osmotic potential. Stomatal conductance and cuticular conductance were lower in the non-irrigated plants. A wide range in CMS among four cultivars was observed. CMS increased with increasing water deficits. EWL increased on leaves of water deficient plants and was positively correlated with cuticular conductance and CMS. Membrane phospholipid content increased in water-stressed plants. CMS as measured by the PEG test, was influenced by EWL, cuticular thickness, and osmotic concentration of leaf tissues. The cultivars which maintained higher CMS, higher EWL, lower cuticular conductance, higher turgor and higher osmotic adjustment under water deficit conditions were identified as drought tolerant.

Cell membrane stability, an indicator of drought tolerance, as affected by applied nitrogen in soyabean

SUMMARYFour soyabean cultivars were grown with two N application rates (50 and 300 kg N/ha) in the field at Hiroshima University, Japan, from June to August 1988. Cell membrane stability (CMS) by the polyethylene glycol (PEG) test, leaf water relations and nutrient concentrations in cell sap and leaf tissues were measured when the plants were 50 days old, in the uppermost fully expanded leaves.Cell membrane stability was higher at the higher N rate, the increase over the lower rate being greater in the cultivars Lee+ and Lee–than in Tamahomare and T201. Leaf water potential was not affected by the higher rate of N application. Osmotic adjustment, which was independent of water stress, was observed with the higher rate of N and it was higher in Lee + and Lee–than in Tamahomare and T201. It is suggested that osmotic potential in leaf tissues may influence CMS measured by the PEG test. Solute concentrations in cell sap and leaf tissues were higher at the higher N rate. Sugar and K were the major contributors to osmotic potential.

Evaluation of Polyethylene Glycol Test for Measuring Cell Membrane Stability in Maize

AbstractCell membrane stability (CMS) of ten maize (Zea mays L.) cultivars was measured by the polyethylene glycol (PEG) test and compared with other nutritional and physiological measurements to examine the nutriophysiological meanings of the test. Osmotic potential of leaf tissues was well correlated with CMS measured as percentage injury in the PEG test and it was suggested that it may have influenced on desiccation treatment in the PEG test. Leaf water potential, stomatal resistance and cuticular resistance did not show any correlation with CMS measured. Cultivars with high leaf water content were high in CMS and were tolerant to desiccation stress in the PEG test. They showed high excised‐leaf water retention capability. Sugar, K. and Ca were the major solutes which contributed to osmotic potential. Potassium concentration in leaf tissues was well correlated with CMS, while sugar was not. It was suggested that K may play another role in increasing CMS in maize apart from its role as an osmotic substance.

Evaluation of polyethylene glycol test for measurement of cell membrane stability in maize

Cell membrane stability (CMS) of three maize (Zea mays L.) cultivars was determined by the polyethylene glycol (PEG) test at different leaf positions and compared with other physiological measurements to clarify the mechanism of the PEG test. Percentage injury in the PEG test was well correlated with the leaf water potential, osmotic potential, leaf thickness, and Ca and Mg concentrations in the leaf tissues and cell sap. It was comparable with the cuticular resistance but did not show any relationship with stomatal resistance. Osmotic potential of leaf tissues may affect the desiccation treatment in the PEG solution. Sugars, K, and Ca were the major contributors to the osmotic potential. Relative contribution of K to the osmotic concentration was higher than that of sugars in maize. Percentage injury in the PEG test was influenced mainly by the osmotic potential, leaf thickness, and Ca and Mg concentrations of leaf tissues.

Nutrio‐Physiological Evaluation of the Polyethylene Glycol Test of Cell Membrane Stability in Maize

Cell membrane stability (CMS) of maize (Zea mays L.) was measured by the polyethylene glycol (PEG) test and compared with the nutrio‐physiological characteristics to examine the relationship of plant processes involved in differential ion leakage. Two pot experiments were conducted in the glasshouse under three soil moisture levels (MPa 0 to −0.05, −0.3 to −0.9, and −1.2 to −1.5) using three cultivars (P‐3358, G‐4578, and FFR‐677) of maize. Leaf water potential, osmotic potential, stomatal resistance, cuticular resistance, excised‐leaf water retention capability, degree of leaf rolling, total plant weight, and total root length as well as the CMS by the PEG test were measured when the plants were 60 d old. Nutrient concentrations in leaf tissues, cell sap, and cell leachate were analysed. Cell membrane stability measured by the PEG test was well related to the other physiological measurements. It was highly or very highly correlated with leaf water potential (r = −0.869**), (significant at P = 0.01) osmotic potential (r = −0.946**), excised‐leaf water retention capability (r = 0.767**), K concentration in leaf tissues (r = 0.757*) (significant at P = 0.05) and cell sap (r = 0.690*), and the degree of leaf rolling. Cell membrane stability appears to be influenced by osmotic potential of leaf tissues. Sugar and K were the major osmotic contributors. In conclusion, we find the PEG test to be a useful measure of drought tolerance in maize.

The Urinary Excretion of Polyethylene Glycol as a Test for Mucosal Integrity in Children with Celiac Disease

We compared the results of various noninvasive tests with small bowel histology in 61 children with celiac disease. The most sensitive predictors of small bowel histology were serum levels of anti-gliadin antibodies (AGAs) (90%) and the urinary excretion of polyethylene glycol (PEG) (69%). The sensitivity for the fecal fat analysis was 61% and for the D-xylose test 34%. The specificity was 96% for both the PEG and the D-xylose tests, 92% for the fecal fat, and 68% for AGAs. The predictive value of the PEG test was significantly better than that of D-xylose (p less than 0.05). The best combination of tests for the prediction of small bowel histology was the PEG test and the measurement of serum levels of AGAs. Agreement in the results of these two tests helps to time appropriately the second and third small bowel biopsies.

Evaluation of polyethylene glycol test of measuring cell membrane stability as a drought tolerance test in wheat

SummaryEffectiveness of the polyethylene glycol (PEG) test for measuring cell membrane stability (CMS) to select drought-tolerant genotypes in wheat was investigated. PEG test was compared with two other tests. Genetic variability of CMS was also investigated.Drought was induced artificially in pot-grown plants and in excised leaves, and percentage injury in leaf tissues by drought stress as measured by CMS was compared with that by PEG test. Percentage injury in leaf tissues of pot-grown plants was not correlated significantly with that by PEG test. However, percentage injury in excised leaves was well correlated with that in PEG test. The results suggest that the PEG test has merit in measuring drought tolerance in wheat. Frequency distribution of CMS in winter wheat lines was closely related to the characteristic pattern of quantitative inheritance and therefore CMS of wheat seems to be controlled by polygene action.