The purpose of our study was to define further the role of bacterial esterases in amniotic fluid obtained from women with chorioamnionitis.
Amniotic fluid samples from 39 patients with ...chorioamnionitis were submitted for bacterial cultures and in vitro assay. Esterase inhibitors diisopropyl fluorophosphate and iodoacetic acid were added and the degree of inhibition calculated. These results were compared with the amniotic fluid culture results. Chi square analysis was performed to compare the results of the esterase assay and the inhibition assay between the uninfected and infected amniotic fluid samples.
Thirty-one patients had positive bacterial cultures, with 21 being infected with gram-negative organisms. All samples showed significant inhibition (range 55% to 82%) with diisopropyl fluorophosphate. There was partial inhibition with iodoacetic acid (range 10% to 30%) in the gram-negative samples but no inhibition in the gram-positive and uninfected samples. Six infected and two uninfected samples were analyzed by using zone electrophoresis with human plasma as a control. Minimal esterase motility was noted in the amniotic fluid samples as compared with that in plasma.
The esterases in amniotic fluid appeared to be of bacterial, not human, origin. Furthermore, different groups of bacteria appeared to produce different esterases in infected amniotic fluid.
Chorioamnionitis plays an important role in perinatal morbidity and mortality. Fast and accurate diagnosis poses a major problem. A prospective study was performed to assess the value of positive ...leukocyte esterase test (Chemstrip 9) for the diagnosis of chorioamnionitis during labor. We evaluated 21 patients with chorioamnionitis in labor at term and used 21 matched control subjects. The sensitivity and specificity of leukocyte esterase activity were compared with those of amniotic fluid cultures, Gram stains, maternal pyrexia and leukocytosis, and fetal tachycardia. The sensitivity in diagnosing chorioamnionitis was 91% and the specificity was 95%. The use of this test strip could provide a rapid, inexpensive screening test for chorioamnionitis.
Chorioamnionitis during pregnancy is a common diagnostic dilemma for the obstetrician. Fast and accurate diagnosis poses the most significant problem. Since leukocytes are known to be released in ...response to infections, examination of amniotic fluid for their presence is an important part of the evaluation for chorioamnionitis. These neutrophils contain several esterases that are not present in serum, urine, or vaginal secretions. The esterases are not influenced by bacteria or by commonly used drugs. We have previously described the reliability of leukocyte esterase (LE) activity for the detection of chorioamnionitis in term pregnancies uncomplicated by other diseases. A prospective study was performed to assess the presence or absence of LE activity to establish normal values in amniotic fluid at various gestational ages prior to term before its use as a possible predictor for chorioamnionitis. Sterile amniotic fluid specimens were obtained from 13 patients undergoing second trimester genetic amniocentesis (with gestational ages varying from 15 to 19 weeks) and from 11 patients with a wide variety of medical problems, undergoing amniocentesis for Rh sensitization or lung maturation studies (with gestational ages ranging from 25 to 27 weeks). All patients with ruptured membranes or preterm labor were excluded. Each amniotic fluid sample was divided into two parts, one of which was transported to the laboratory for aerobic and anaerobic cultures and the other used for LE activity detection as measured by dipstick. The LE results were retrospectively compared with the results of the cultures. LE activity was always found to be negative when the culture results were negative. negative.
Accurate and rapid diagnosis of chorioamnionitis poses a major diagnostic dilemma. We previously reported that leukocyte esterase activity in amniotic fluid, as measured by dipstick assay, could be ...used as an aid in the diagnosis of chorioamnionitis. This study examines the effectiveness of an in vitro spectrophotometric assay of esterase activity in amniotic fluid. We define baseline levels of esterase activity in uninfected amniotic fluid and demonstrate a quantitative increase when infection is present. Fifty-seven amniotic fluid samples obtained at second- and third-trimester amniocenteses were divided into three parts, one for culture and two for a comparison of esterase activities by the dipstick and spectrophotometric methods. In this study, the spectrophotometric assay, because of its higher specificity and sensitivity in the determination of elevated esterase activity, was shown to be more reliable for predicting chorioamnionitis than either the dipstick or culture method.
Several authors have described the bacterial growth-altering properties of amniotic fluid. We examined Group B Streptococcus growth in aseptically obtained amniotic fluid in vitro after altering its ...zinc, phosphorus, and meconium contents. Zinc and phosphorus levels were calculated in amniotic fluid and in meconium. Separate solutions of zinc and phosphorus were added to yield concentrations of 0.7, 7.0, 70, and 700 mumol. The solutions were incubated with Group B Streptococcus III 893 and Escherichia coli C5 strains, and 24-hour growth curves were plotted. Meconium, 0.5 mg/ml, was added to each amniotic fluid + zinc and amniotic fluid + phosphorus solution, and growth curves were plotted. The rate of proliferation of Group B Streptococcus varied directly with the zinc concentration (700 = 70 greater than 7 greater than 0.7 mumol) and inversely with the phosphorus content (700 less than 70 less than 7 = 0.7 mumol). Meconium enhanced the proliferative effect of zinc and hindered the inhibitory effect of phosphorus. Thus one possible mechanism whereby meconium enhances bacterial growth in amniotic fluid may be by alteration of zinc-to-phosphorus ratios.
Assessment of leukocyte esterase activity in amniotic fluid for the rapid and reliable diagnosis of chorioamnionitis has been demonstrated previously. We compared in vitro inhibition of esterase ...activity in amniotic fluid with bacterial cultures to identify the origins of the specific esterases released by the infecting organisms. One hundred forty-one samples were tested (90 uninfected, 51 infected). Each sample was evaluated for Gram stain, cultures, and an in vitro esterase assay followed by ebelactone inhibition. Forty-two patients had positive amniotic fluid cultures. Ebelactone produced varying degrees of inhibition of esterase activity (range, 20% to 60%) in the uninfected samples and in those infected with gram-negative organisms. There was no inhibition in the samples infected with gram-positive organisms. Thus different groups of bacteria may elicit the production of different and specific esterases in infected amniotic fluid, as shown by the differences in in vitro inhibition.
L' amelioration de la tolerance a la secheresse est un objectif majeur pour les selectionneurs qui travaillent en zone mediterraneenne. La discrimination isotopique du carbone (delta) a ete proposee, ...il y a quelques annees, comme critere predictif du rendement et de l' efficience d' utilisation de l' eau en conditions de secheresse. L' utilisation de ce critere en selection presente plusieurs avantages. Il s' agit tout d' abord d' un critere integratif, associe a l' efficience de transpiration d' un organe, ou de la plante entiere, sur une periode longue du cycle de developpement. D' autre part, le caractere discrimination du carbone est tres etroitement correle au rendement, et presente une forte heritabilite. Les principaux objectifs du travail presente consistent a examiner les relations entre la discrimination du carbone mesuree au niveau de divers organes, et la stabilite du rendement, evaluee a partir d' essais realises sur plusieurs sites. L' etude a ete effectuee dans 6 environnements des Hautes-Plaines Setifiennes (Algerie), sur 15 varietes de ble dur (varietes locales et ameliorees). Dans l' un des sites, les valeurs de discrimination ont ete evaluees dans plusieurs organes de la plante (grain, feuille-etendard, col de l' epi, rachis et barbes). Concernant les valeurs de delta, les differents organes etudies se classent dans l' ordre decroissant suivant: feuille-etendard, barbes et rachis, col de l' epi et grain. Le rendement apparait tres lie aux valeurs de discrimination du carbone dans le grain, la feuille-etendard et le col de l' epi (respectivement deltaG, deltaF et deltaC). Les correlations les plus fortes sont notees avec deltaG. La variation de ce dernier caractere est principalement expliquee par la variation de delta dans la feuille-etendard et le col de l' epi. Six varietes ont egalement ete testees dans cinq autres environnements. Des interactions genotype x environnement faibles sont notees, et les valeurs de deltaG, deltaF et deltaC mesurees sur un site sont fortement correlees aux rendements obtenus dans la majorite de ces environnements. La variete donnant les meilleurs rendements dans la plupart des environnements consideres (Waha) presente egalement les valeurs de deltaG et deltaF les plus elevees ainsi que la plus forte contribution de deltaF a deltaG. L' utilisation de delta comme critere de selection pour la tolerance a la secheresse et la stabilite de rendement, ainsi que l' interet de l' evaluer dans differents organes sont discutes.
