The distinction between transudates and exudates

Summary The first step in the diagnosis of pleural effusions is the distinction between exudates and transudates. The aim of this study was to evaluate the usefulness of various parameters for the differentiation of pleural exudates and transudates. We recorded clinical characteristics, final diagnoses, and measured pleural fluid and serum levels of albumin, protein, LDH, cholesterol, and bilirubin of 381 consecutive patients with pleural effusion. Seventy-one (23%) pleural effusions were transudates and 236 were exudates. As a single criterion, the pleural fluid to serum albumin ratio >0.5 was the most accurate parameter (88.4%). An albumin gradient of 12 g/l had an accuracy of 75% in the whole population but it detected 96% of transudative effusions in patients treated with diuretics. Light’s criteria and abbreviated Light’s criteria had similar accuracies, 87.8% vs. 88.2%, respectively. In conclusions, different alternatives can be used instead of Light’s criteria.     

Leukotriene B4, polymorphonuclear leukocytes and inflammatory exudates in the rat

Leukocyte numbers and Leukotriene B₄- (LTB₄-) and LTC₄-immunoreactivity were measured in inflammatory exudates obtained from sponges impregnated with several irritants implanted subcutaneously in the rat. Sponges containig 1% uric acid, carragennan or zymosan were implanted for 5h and compared to saline sponges. Increases in leukocyte numbers and LTB₄-immunoreactivity were found in the presence of irritants, the highest concentrations being observed in the presence of zymosan. The presence of LTB₄ was confirmed by liquid chromatographic (HPLC) analysis. A time course study was carried out with zymosan-impregnated sponges and the maximal rate of leukocyte infiltrations was found to coincide with the maximal levels of LTB₄-immunoreactivity. The LTC₄-immunoreactivity was low and following analysis by HPLC was concluded to be unrelated to leukotrienes. The levels of LTB₄-immunoreactivity, but not the numbers of leukocytes, were elevated compared to corresponding controls in sponges containing 0.01% ionphore A23187 (untreated rats) or in sponges containing zymosan (rats pretreated with indomethacin; 3 and 10 mg/kg p.o.). Impregnation of sponges with 3 × 10⁻⁶M LTB₄ but not 3 × 10⁻⁷M LTB₄ induced a significant leukocyte migration. It was concluded that LTB₄ can induced leukocyte migration into sponge exudates in the rat but that measurements of LTB₄ in such exudates can not be correlated with the degree of leukocyte infiltration.     

Root exudates of plants

Summary The effect of temperature on the exudation of sugars and amino acids from germinating seeds of maize and cucumber and the effect of the so called cold shock on root exudation of plant seedling was studied. After the first forty-eight hours the exudation of these compounds from germinating seeds generally rises in proportion to the temperature. However, certain relative changes were observed in the composition of the exudates. Exudation of maltose and fructose with arabinose, for example is lower at 28°C than at 19°C.When plants previously growing under favourable temperature conditions were exposed for three days to a lower temperature, there was a several times higher exudation from the roots of maize and a marked rise in exudation from roots of cucumber in comparison with control plants. In the exudates of maize affected by cold shock 3 new oligosaccharides and fructose with saccharose in addition to previously detected substances were found.     

The gum exudates from Brachystegia and Julbernardia species

Analytical data are presented for the water-soluble gum exudates from Brachystegia glaucescens, B. spiciformis, and Julbernardia globiflora. They are acidic polysaccharides containing glucuronic acid, 4-O-methylglucuronic acid and galacturonic acid, together with galactose, minor amounts of arabinose, and relatively high proportions of rhamnose. The exudate from B. glaucescens is of particular interest in having high molecular weight, high intrinsic viscosity, and a high methoxyl content. The nitrogen content of all three gums is low, but amino acid analysis shows that proteinaceous components are involved, as in the gum exudates from other genera.     

Root exudates of plants

Summary The composition of the root exudates of barley and wheat in the initial growth phases was investigated; amino acids, organic acids, sugars and certain aromatic compounds could be identified. A knowledge of the composition of root exudates is important from the standpoint of the interaction between the plants and the micro-organisms in the rhizosphere. Some aspects of the rhizosphere effect connected with the present work are discussed.     

Root exudates of plants

Summary Comparisons have been made of the amount and composition of seed and seedling exudates in barley, wheat, cucumber, and bean. Except in the case of wheat a greater proportion of the total nitrogen content in the seed exudates was formed by protein and peptide nitrogen than by nitrogen of free amino acids. In contrast, the greater part of the total nitrogen in the exudates of seedlings was formed by free amino acid nitrogen, except in the case of barley. Peptides represented 8 to 26 per cent of the protein and peptide fraction in seed exudates, the highest amount being found in bean. On an equal weight basis, the spectrum of amino acids released from seeds and seedlings differed little between barley, wheat and cucumber; greater differences were observed in bean exudates. Seedlings exuded reducing substances to a considerably greater extent than seeds. The spectrum of reducing sugars in seed and root exudates differed greatly, especially in the case of keto sugars. Differences in the organic acid spectra were small, except for bean plants, the seedling exudate of which contained more organic acids with a richer spectrum than seed exudate. Both seeds and seedlings of cucumber exuded a small quantity and a poor spectrum of organic acids.     

Root exudates of plants

Summary The release of substances from wheat roots was found to be directly related to the growth of the root system. Plants whose root system did not grow released almost no exudates.When exudate concentration in the vicinity of the roots was lowered by frequent replacements of the nutrient solution or by a simultaneous cultivation of exudate-utilizing bacteria, the release of exudates was enhanced. In axenic wheat cultures, the amount of exudates during a 12-day cultivation with 2- or 4-day intervals between medium replacements represented 50% of root dry weight and 12% of whole plant dry weight.Wheat plants cultivated in the presence of the bacteriumPseudomonas putida released up to double the amount of exudates compared with axenic variants.     

Extracellular pH affects inflammatory cell production of superoxide and nitric oxide

Previous research has described how high cellular metabolism creates an acidic environment in inflammatory cells during respiratory burst. The aim of our work was to describe the acid-base dependence of exudate in superoxide (O2.-) and nitric oxide (NO.) generation by inflammatory cells from a carrageenan-granuloma. Although the carrageenan solution was alkaline (pH 7.74 when equilibrated with air) the exudate showed an acidification that stabilised at around 7 units of pH. A notable hypercapnia, but not hypoxia, was found in the exudate at up to 24 h. The effect of extracellular acidosis on O2.- and NO. production by inflammatory cells was also studied. The maximum O2.- production and the lowest levels of NO. were found at pH 7, which was closer to the pH of the granuloma-pouch. These results suggest that experiments with inflammatory cells ex vivo should be carried out at an identical pH to that found in vivo in order to reproduce the physiological mechanisms of free radical generation during inflammatory processes.     

The influence of cumin seed exudates on fungal spore germination

Summary Effect of cumin seed exudates on spore germination of Curvularia lunata, Alternaria solani and Colletotrichum capsici was studied in the laboratory. Three-hour exudate obtained for first 3-hour favoured initial protrusion but inhibited subsequent growth of the germ tubes. Two-hour exudate obtained between 5 and 7 hours after soaking was suggested to have no effect on initial protrusion but was found to have promotive effect on subsequent growth of germ tube. Short treatment with inhibitor for 45 minutes followed by a treatment with promotor ensured high germination and uniform germ tube growth. Modifying effects on the spermatosphere and adaptive significance of sequential exudation are discussed. re]19730125     

The hydroxyproline content of gum exudates from several plant genera

Amino acid compositions are presented for the proteinaceous components of the gum exudates from Albizia glaberrima, A. sericocephala and A. anthelmintica; Aralia elata; Azadirachta indica; Entada africana; Grevillea robusta; Lannea humilis and L. schimperi; and Moringa oleifera. The gums from four of these genera (Albizia, Azadirachta, Grevillea and Moringa) contain low proportions, and the others contain high proportions, of hydroxyproline. High proportions of hydroxyproline were found previously in gum exudates from genera within the Leguminosae (Acacia, Astragalus and Prosopis), to which must now be added Entada and Leucaena. In contrast, however, Albizia spp. (Leguminosae) have low proportions of hydroxyproline, whereas the non-leguminous genera Aralia and Lannea have high proportions of hydroxyproline.     

The amino acid composition of gum exudates from Prosopis species

The amino acid compositions of the proteinaceous components of the gum exudates from Prosopis alba, P. chilensis, P. glandulosa, P. laevigata, P. torreyana and P. velutina, and for a sample of commercial gum mesquite, are presented. In agreement with data published previously for the polysaccharide components of their gums, only minor differences in composition are shown by these species. The amino acid compositions are characterized by very high proportions of hydroxyproline and by high proportions of proline and serine; these three amino acids account for 62.5% of those present in the gum from Prosopis velutina. The amino acid compositions of these Prosopis gums are remarkably similar to that established recently for the gum from Acacia senegal (gum arabic).