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Biomedical subjects

D B Cotton

Publications and source records attributed to D B Cotton.

At least 37 records · Page 2Linked to original sources

Changes in health care delivery: a threat to academic obstetrics.

OBJECTIVE: Our purpose was to examine the effect of anticipated health care policy changes on delivery trends at leading academic obstetric institutions. STUDY DESIGN: The 51 centers in the United States with the most Society of Perinatal Obstetricians presentations in the past 2 years were surveyed regarding annual deliveries from 1990 to 1993 and reasons for any changes. Analysis of variance and chi 2 analysis were used as appropriate. RESULTS: Complete data were available from 43 hospitals representing 39 institutions. Their 1990 to 1993 delivery rates declined faster than United States delivery rates (12.3% vs 2.0%, p < 0.0001). The largest hospitals (> 6000 deliveries) had a decline of 18.2% compared with declines of 9.0% for medium and 0.9% for small hospitals (< 2500 deliveries). Regionally the greatest impact was seen in the West and the South, with 22% and 12% declines, respectively (p < 0.05). Reasons cited for the decline included competition from private or community physicians or hospitals (59%) and managed care (15%). CONCLUSION: As the national health care debate focuses on cost containment and coverage, we believe the potential effects of national policy on research and education should be considered. Continued selective reduction in deliveries at academic institutions can be expected to adversely affect research and education.

Delivery of Health Care↗

Differential regulation of seizure activity in the hippocampus of male and female rats.

OBJECTIVE: The aim of the current study was to directly examine and compare the susceptibility to N-methyl-D-aspartate-induced seizures in male versus female rats. We also sought to compare the anticonvulsant effects of magnesium sulfate in these two groups. STUDY DESIGN: Eighteen female and 10 male rats were stereotaxically implanted with a chronic bipolar recording electrode in the hippocampus and an injection cannula in the lateral cerebral ventricle. After 1 week rats randomly received an intravenous injection of 90 mg/kg magnesium sulfate or saline solution control. Fifteen minutes after the infusion rats were given the convulsant N-methyl-D-aspartate at a dose of 5 micrograms/microliters by direct intraventricular injection. Electrical seizure activity was thereafter assessed for 20 minutes. All data were analyzed by the Mann-Whitney U test and Student t test. RESULTS: In saline solution-treated rats receiving the convulsant N-methyl-D-aspartate, females had significantly lower total duration (p < 0.01) and total number of seizures (p < 0.05) compared with the male rats. The initial seizure was not affected by gender. In the female animals magnesium sulfate significantly reduced first seizure duration (p < 0.01) compared with saline solution controls. In males magnesium sulfate reduced both total duration (p < 0.05) and total seizure number (p < 0.05) compared with saline solution-treated animals. CONCLUSION: N-methyl-D-aspartate-induced seizure activity is more severe in males versus female rats. Magnesium sulfate's effect on N-methyl-D-aspartate-induced seizures is also dependent on gender. We speculate that seizure regulation may be hormonally influenced.

Animals↗

Premature parturition is characterized by in utero activation of the fetal immune system.

OBJECTIVE: At birth the fetus emerges from a sterile environment into a nonsterile one. This process is associated with activation of the fetal immune system which protects the fetus against infection in the newborn period. We conducted this study to determine whether activation of the monocyte-neutrophil system occurs in fetuses before premature birth. STUDY DESIGN: Forty patients in premature labor with intact membranes underwent cordocentesis for research purposes. Fetal blood was analyzed with the use of flow cytometry to measure the cell surface markers CD11c, CD13, CD15, and CD67, which are associated with monocyte and neutrophil activation, and CD14 and CD63, which were used as controls. RESULTS: Twenty-eight percent (11/40) of the infants were delivered prematurely within 72 hours of entering the study while the remainder were delivered at term. Our data clearly indicate that premature infants delivered within 72 hours had a higher percentage of CD11c, CD13, CD15, and CD67 than those delivered at term. In contrast, there were no significant differences in the percentages of CD14 and CD63. CONCLUSION: Activation of the monocyte-neutrophil system exists in fetuses destined for premature delivery. These findings indicate that premature parturition is associated with in utero immune system activation.

Adolescent↗

The biophysical profile as a tool for prediction of preterm delivery.

Our objective was to determine if any of the following parameters is a predictor of preterm delivery: gestational age, cervical dilatation, or biophysical profile score.Sixty-two women with certain dates, intact membranes, and preterm contractions more frequent than 300 min underwent a 30-min ultrasonographic assessment of fetal breathing movements, fetal tone, fetal movement and amniotic fluid volume, each of which was scored as 0, 1, or 2 before any tocolytics were given. The total score (0-8) was calculated and cervical dilatation was recorded. All women were subsequently placed on tocolytics. Data were analyzed using survival analysis with stepwise regression of the covariates to determine the predictive values of the total score, its individual parameters, gestational age, and cervical dilatation to the outcome variable of hours to delivery. Gestational age, cervical dilatation and time interval to delivery were categorized and entered into a logistic regression model with the total score and its components to determine predictive odds.Total score (p < 0.0001) and cervical dilatation (p < 0.0001) were the most significant variables associated with time interval to delivery, followed by gestational age (p = 0.035). When the individual biophysical parameters were entered into the model, fetal tone (p < 0.0001), cervical dilatation (p < 0.0001) and gestational age (p < 0.014) were the only variables related to time interval to delivery. Predictive odds of delivery in less than 48 h in relation to fetal tone and cervical dilatation were calculated. Total score, fetal tone, and cervical dilatation were strongly associated with time interval to delivery. Our study did not support fetal breathing movements as a predictor of preterm delivery.

Journal Article↗

Magnesium is more efficacious than phenytoin in reducing N-methyl-D-aspartate seizures in rats.

OBJECTIVE: Although magnesium sulfate is one of the most commonly used agents for seizure prophylaxis in preeclampsia, its efficacy relative to other anticonvulsants is incompletely investigated. The underlying mechanisms of eclamptic seizures are unknown, and there is currently no universally accepted animal model for eclampsia. However, one commonly used method for studying the relative efficacy of antiepileptic drugs is through their effect on N-methyl-D-aspartate-induced seizures. Our aim was to compare the anticonvulsant effects of phenytoin and magnesium sulfate in an N-methyl-D-aspartate-induced seizure model. STUDY DESIGN: Twenty-one female rats were each stereotaxically implanted with a chronic indwelling bipolar recording electrode in the hippocampus and an injection cannula in the lateral cerebral ventricle. After 7 days animals were randomly given 90 mg/kg magnesium sulfate (n = 7), 50 mg/kg phenytoin, or saline solution (n = 7) intravenously. Fifteen minutes after the infusions animals were given 20 micrograms/microliters N-methyl-D-aspartate by direct intraventricular injection, and seizure activity was assessed for 20 minutes thereafter. All data were analyzed with the Mann-Whitney test. RESULTS: When compared with saline solution controls, total duration of seizure activity in animals treated with magnesium sulfate was significantly decreased (p < 0.05) and time to onset of seizure activity was significantly increased (p < 0.05). However, rats that received phenytoin did not show significant changes in these parameters. The post-N-methyl-D-aspartate seizure mortality rate was 50% in the saline solution controls and 29% in the phenytoin group, whereas none of the rats that received magnesium sulfate died. CONCLUSION: These results suggest that magnesium sulfate is a significantly more effective prophylactic agent than phenytoin for N-methyl-D-aspartate-induced seizures.

Animals↗

Hydrolaparoscopy in the rabbit: a fine model for the development of operative fetoscopy.

OBJECTIVE: Our goal was to become adept at performing laparoscopic procedures within a fluid medium and at using miniature instruments in a small animal model. STUDY DESIGN: Adult female New Zealand rabbits underwent carbon dioxide laparoscopy while they were under general anesthesia with the use of 2 mm instruments. The abdominal cavity was filled with lactated Ringer's solution. Visualization of the intraabdominal organs and surgical procedures were performed below the fluid level. RESULTS: Excellent visualization of the abdominal organs below the fluid level was obtained. Several surgical tasks were accomplished, including cutting and coagulation of the uterine horns with monopolar electrocautery, creation of a defect in the mesovarium and mesometrium, extracorporeal knot tying, and intraabdominal cutting of suture material. Relatively high amounts of energy were needed during electrocautery within the liquid medium (> 25 W). Occasional fluid and gas leakage through the skin punctures was prevented with accessory clamps. CONCLUSION: Hydrolaparoscopy can be performed in the rabbit with miniature instruments. As it simulates the human intraamniotic environment, it is a useful model for the development of operative fetoscopy.

Abdomen↗

Effect of endoscopic white light on the developing visual pathway: a histologic, histochemical, and behavioral study.

OBJECTIVE: We examined the potential teratogenic effect of endoscopic white light on the developing visual pathways. STUDY DESIGN: The right eye of chicken embryos (n = 22) was exposed to maximal endoscopic light intensity on day 10 of development. At day 17 of development the histologic characteristics of the light-exposed retinas were compared with those of the control embryos (n = 4). Normal functioning of the light-exposed eye was assessed by intravitreal injection of wheat germ agglutinin-horseradish peroxidase and observation of its axonal transport pattern to the diencephalic and mesencephalic visual centers. Axonal transport patterns were compared with those found in previous studies of normal embryos. Behavioral feeding patterns were compared between two groups of newly hatched chickens, one exposed to endoscopic light after hatching (n = 13) and the other, an unexposed control group (n = 12). RESULTS: No evidence of retinal damage, altered axonal transport or altered feeding patterns could be found between control and experimental animals. CONCLUSION: Endoscopic white light does not appear to be harmful to the developing retina and visual pathway.

Animals↗

Topographic differences in amniotic fluid concentrations of prostanoids in women in spontaneous labor at term.

These studies were designated to determine if there are differences in prostanoid concentrations between amniotic fluid (AF) retrieved transvaginally from the membrane forebag (lower or forebag compartment) and fluid retrieved by transabdominal amniocentesis from the 'upper compartment' in women in labor. Fluid was retrieved from 53 women in active labor who underwent transabdominal and transvaginal amniocentesis. Fluid was assayed for prostaglandin E2 (PGE2) and prostaglandin F2 alpha (PGF2 alpha), 13,14-dihydro-15-keto-prostaglandin F2 alpha (PGFM), thromboxane B2 (TXB2), and 6-keto-prostaglandin F1 alpha (6-k-PGF1 alpha) using sensitive and specific radioimmunoassays. Concentrations of all prostanoids measured were significantly higher in fluid retrieved by transvaginal than transabdominal amniocentesis; the magnitude of the increase (measured as the ratio of concentrations in the lower/upper compartment) was higher for PGF2 alpha and TXB2 than for the other prostanoids measured; for each prostanoid measured, there was a significant correlation between the concentration in the upper and lower compartment.

Amniocentesis↗

The natural interleukin-1 receptor antagonist in the fetal, maternal, and amniotic fluid compartments: the effect of gestational age, fetal gender, and intrauterine infection.

OBJECTIVES: The interleukin-1 receptor antagonist is a newly discovered cytokine that blocks the biologic effects of interleukin-1 in vitro and in vivo. This cytokine is a physiologic component of amniotic fluid and is considered to be of critical importance in the homeostasis of the cytokine network. This study was undertaken to systematically examine the bioavailability of interleukin-1 receptor antagonist in the maternal, fetal, and amniotic fluid compartments during term and preterm parturition in women with and without microbial invasion of the amniotic cavity. STUDY DESIGN: The patient population consisted of (1) pregnant women in the midtrimester (n = 42), (2) patients who underwent cordocentesis for diagnostic purposes (n = 39), (3) patients with preterm labor (n = 126), (4) women with term gestation (n = 102), and (5) healthy nonpregnant women (n = 8). Amniotic fluid was cultured for aerobic and anaerobic bacteria, as well as Mycoplasma sp. Interleukin-1 receptor antagonist concentrations were determined by enzyme-linked immunoassay in maternal and fetal plasma, amniotic fluid, and neonatal urine. Microbial invasion of the amniotic cavity was defined as the presence of a positive amniotic fluid culture for microorganisms. RESULTS: (1) Interleukin-1 receptor antagonist was normally present in fetal plasma samples obtained by cordocentesis, and its concentration increased with advancing gestational age (n = 39; r = 0.61, p < 0.001). (2) Patients at term not in labor had higher amniotic fluid interleukin-1 receptor antagonist concentrations than patients in the midtrimester (median 40.1 ng/ml, range 5.7 to 213.1 vs median 16.2 ng/ml, range 3.2 to 62.2, respectively, p < 0.001). (3) Amniotic fluid and cord plasma interleukin-1 receptor antagonist concentrations were significantly higher in patients with preterm labor and microbial invasion of the amniotic cavity than in those without microbial invasion of the amniotic cavity (amniotic fluid: median 219.9 ng/ml, range 35.4 to 504 vs median 80.6 ng/ml, range 24.3 to 399, respectively, p < 0.001; umbilical cord plasma: median 4.8 ng/ml, range 0.3 to 167.0 vs median 1.0 ng/ml, range 0 to 276.0, respectively, p < 0.05). In contrast, these differences were not found in patients with term labor either with or without microbial invasion of the amniotic cavity. (4) In both term and preterm patients the amniotic fluid and neonatal urine concentrations of interleukin-1 receptor antagonist were significantly higher in female fetuses than in male fetuses (amniotic fluid, preterm: median 191.9 ng/ml, range 51.6 to 504.0 vs median 61.1 ng/ml, range 11.5 to 284.9, respectively, p < 0.001; amniotic fluid, term: median 58.7 ng/ml, range 25.5 to 264.0 vs median 33.9 ng/ml, range 3.4 to 132.4, respectively, p < 0.001; neonatal urine: median 317 ng/ml, range 59.0 to 440.8 vs median 12.2 ng/ml, range 2.5 to 61.6, respectively, p < 0.005). CONCLUSIONS: (1) Interleukin-1 receptor antagonist is physiologically present in the fetal, maternal, and amniotic fluid compartments; (2) microbial invasion of the amniotic cavity in the preterm gestation is associated with a significant increase in the concentrations of this cytokine in the fetal and amniotic fluid compartments but not in maternal plasma; (3) fetal urine is a source of amniotic fluid interleukin-1 receptor antagonist; (4) fetal plasma interleukin-1 receptor antagonist concentrations increase with gestational age; (5) there is a significant effect of fetal gender in amniotic fluid and neonatal urine concentrations of interleukin-1 receptor antagonist.

Amnion↗

Magnesium sulfate versus phenytoin for seizure prevention in amygdala-kindled rats.

OBJECTIVE: Magnesium sulfate is widely used for seizure prophylaxis in preeclampsia-eclampsia. However, its anticonvulsant effects in other types of seizures have not been proved. Diphenylhydantoin has been widely characterized as the "gold standard" of anticonvulsants. In this study we compared the anticonvulsant effects of therapeutic blood levels of magnesium sulfate and phenytoin in seizures generated in amygdala-kindled rats. STUDY DESIGN: Eighteen male rats had a bipolar electrode stereotaxically implanted into the central nucleus of the amygdala. After recovery an electrical seizure threshold was determined for each rat. Rats were stimulated twice daily at their seizure thresholds (i.e., kindling) until three consecutive generalized tonic-clonic seizures occurred. Kindled rats randomly received one of the following intravenous injections in a volume of 1.5 ml/kg: saline solution, magnesium sulfate (30, 60, or 90 mg/kg), or phenytoin (12.5, 25, or 50 mg/kg). Fifteen minutes after injection rats were stimulated at their seizure thresholds, and electrical and behavioral seizure activity was assessed. Statistical comparisons were made by analysis of variance and post hoc comparisons when appropriate. RESULTS: Magnesium sulfate had no effect on any of the seizure parameters assessed. Phenytoin significantly reduced seizure duration (p < 0.01), duration of postictal depression (p < 0.01), and behavioral seizure stage (p < 0.01). CONCLUSION: Amygdala-kindled seizures are more potently inhibited by phenytoin than by magnesium sulfate.

Amygdala↗

Prenatal diagnosis of sirenomelus with color Doppler ultrasonography.

Sirenomelus is an invariably lethal congenital anomaly characterized by complete or nearly complete fusion of the lower extremities that occurs in 1 of 60,000 births. In about 50% of cases this condition cannot be diagnosed prenatally because of the associated oligohydramnios that precludes a detailed examination of the fetus. We present a case of sirenomelus in which prenatal diagnosis was aided by color Doppler ultrasonography; visualization of the vitelline artery as a single, large intraabdominal vessel that did not branch in the fetal pelvis but rather coursed ventrally into the umbilical cord proved to be diagnostic of this rare condition. Color Doppler flow ultrasonography is a valuable tool for the prenatal diagnosis of sirenomelus.

Adult↗

Systemic and local cytokine profiles in endotoxin-induced preterm parturition in mice.

OBJECTIVE: Our purpose was to determine whether endotoxin-induced preterm parturition is preceded by a change in the maternal serum and amniotic fluid concentrations of tumor necrosis factor-alpha, interleukin-6, and interleukin-1 alpha. STUDY DESIGN: C3H/HeN pregnant mice at 15 days of gestation (70% gestation) were randomized to receive an intraperitoneal injection of phosphate-buffered saline solution or lipopolysaccharide (50 micrograms/mouse). Blood (n = 93) and amniotic fluid (n = 58) were collected at 1, 4, and 10 hours after lipopolysaccharide injection. Tumor necrosis factor-alpha, interleukin-6, and interleukin-1 alpha were determined with sensitive and specific enzyme-linked immunoassays. RESULTS: The injection-to-delivery interval was shorter in mice injected intraperitoneally with 50 micrograms lipopolysaccharide than in phosphate-buffered saline solution-treated mice (median 15.5 hours, range: 10 to 105 hours vs median 88.5 hours, range: 53 to 105 hours; p < 0.001). In comparison with phosphate-buffered saline solution-treated mice, a distinct serum cytokine pattern was observed in lipopolysaccharide-treated mice. Concentrations of tumor necrosis factor-alpha were detectable 1 and 4 hours after lipopolysaccharide injection (median 874 pg/ml, range: < 100 to 8000 pg/ml, p < 0.001; and median 263 pg/ml, range: < 100 to 927 pg/ml, p < 0.001, respectively). Concentrations of interleukin-6 were elevated at 1, 4, and 10 hours (median 11.8 ng/ml, range: 6 to 500 ng/ml, p < 0.001; median 27.1 ng/ml, range: 4.5 to 192 ng/ml, p < 0.001; median 1.95 ng/ml, range: < 0.05 to 35 ng/ml, p < 0.015, respectively). Concentrations of interleukin-1 alpha were significantly increased 4 hours after lipopolysaccharide injection (median 102 pg/ml, range: < 15 to 306 pg/ml, p < 0.001). A cytokine pattern distinct from serum was observed in amniotic fluid of lipopolysaccharide-treated mice. In comparison with controls, concentrations of interleukin-6 were significantly elevated 4 and 10 hours after treatment with lipopolysaccharide (median 0.88 ng/ml, range: 0.40 to 2.7 ng/ml, p < 0.025; and median 4 ng/ml, range: 1.9 to 33.6 ng/ml, p < 0.001, respectively). Interleukin-1 alpha was elevated 10 hours after lipopolysaccharide treatment (median 185.3 pg/ml, range: 38 to 511 pg/ml, p < 0.015). Tumor necrosis factor-alpha was not significantly increased in amniotic fluid. CONCLUSION: Preterm delivery after lipopolysaccharide administration is preceded by the appearance of dramatic increases in maternal serum concentrations of tumor necrosis factor-alpha, interleukin-6, and interleukin-1 alpha and in amniotic fluid concentrations of interleukin-6 and interleukin-1 alpha.

Amniotic Fluid↗

Interleukin-1 receptor antagonist (IL-1ra) production by human amnion, chorion, and decidua.

PROBLEM: This study was conducted to determine whether (1) conditioned media from unstimulated primary cultures of human amnion, chorion, or decidua contain detectable concentrations of IL-1ra in vitro, and (2) bacterial endotoxin (LPS), tumor necrosis factor-alpha (TNF-alpha), or IL-1-beta (IL-1 beta) stimulate amnion, chorion, or decidua to produce increased amounts of IL-1ra. METHOD: Placentae were obtained from women at term with intact membranes before the onset of labor. Amnion, chorion, and decidual cells were isolated by standard procedures and grown to confluence. Cells were then cultured in quadruplicate for 16 h in tissue culture medium supplemented with 10% fetal calf serum or, additionally, with various concentrations of Escherichia coli LPS, TNF-alpha, or IL-1 beta. Culture supernatants were collected, and concentrations of IL-1ra were quantitated by a sensitive and specific enzyme-linked immunosorbent assay for IL-1ra. RESULTS: Results showed that primary cultures of amnion and chorion from 4 of 9 and decidua from 10 of 12 placentae had detectable rates of production of IL-1ra (ranges: 0.08-6.5, 0.42-12.1, and 1.55-96.5 pg IL-1ra/microgram protein/16 h, respectively). In addition, LPS (10-1,000 ng/ml) and IL-1 beta (0.1-10 ng/ml), but not TNF-alpha (0.01-100 ng/ml), stimulated decidual cells to release/secrete increased amounts of IL-1ra compared with media alone (range: 2.5-400 pg IL-1ra/microgram protein/16 h, P < 0.0001). In contrast, neither LPS, TNF-alpha, or IL-1 beta could stimulate amnion or chorion to release/secrete IL-1ra. CONCLUSIONS: These results indicate (1) that amnion, chorion, and predominantly decidua, can release or secrete IL-1ra in vitro, and (2) that LPS and IL-1 beta can stimulate decidual cells to produce increased amounts of IL-1ra.

Amnion↗

Macrophage inflammatory protein-1 alpha in term and preterm parturition: effect of microbial invasion of the amniotic cavity.

PROBLEM: This study was conducted to determine whether: (1) gestational age, parturition, and microbial invasion of the amniotic cavity (MIAC) are associated with changes in amniotic fluid concentrations of immunoreactive macrophage inflammatory protein-1 alpha; (2) amniotic fluid concentrations of macrophage inflammatory protein-1 alpha are correlated with the white blood cell count and the concentrations of interleukin-8 in amniotic fluid. METHOD: Amniotic fluid was retrieved by amniocentesis from 126 patients; 54 women with preterm labor and intact membranes (no MIAC-delivery at term, N = 21; no MIAC-preterm delivery, N = 16; MIAC-preterm delivery, N = 17); 62 patients at term (no labor, N = 19; labor-no MIAC, N = 20; labor-MIAC, N = 23); and 10 patients in the midtrimester of pregnancy. Amniotic fluid was cultured for aerobic, anaerobic and Mycoplasma species. Determinations of amniotic fluid macrophage inflammatory protein-1 alpha and interleukin-8 were performed with immunoassays validated for amniotic fluid (sensitivity: 14.2 pg/ml and 0.3 ng/ml, respectively). Kruskal-Wallis analysis of variance (ANOVA) for censored data, Mann-Whitney U test and Spearman's rank correlation were performed for analysis. RESULTS: 1) Amniotic fluid macrophage inflammatory protein-1 alpha was present in only 31.0% (9/29) of patients not in labor (midtrimester and term). 2) Patients with preterm labor and MIAC had higher amniotic fluid concentrations of macrophage inflammatory protein-1 alpha than those without MIAC (no MIAC-delivery at term: median 0.0 pg/ml, range 0.0-221.2; no MIAC-preterm delivery: median 37.4 pg/ml, range 0.0-494.6; MIAC-preterm delivery: median 7171.0 pg/ml, range 402.5-37994.0; P < 0.00001). 3) Among patients at term, MIAC was associated with higher concentrations of amniotic fluid macrophage inflammatory protein-1 alpha than patients without MIAC (no labor: median 0.0 pg/ml, range 0.0-25.6; labor-no MIAC: median 16.7 pg/ml, range 0.0-161.6; labor-MIAC: median 103.8 pg/ml, range 0.0-4349.0, P < 0.001). 4) Among patients in preterm labor, a strong correlation was found between amniotic fluid concentrations of macrophage inflammatory protein-1 alpha and interleukin-8 (r = 0.9, P < 0.00001) and between amniotic fluid macrophage inflammatory protein-1 alpha concentrations and amniotic fluid white blood cell count (r = 0.6, P < 0.0001). CONCLUSIONS: (1) Macrophage inflammatory protein-1 alpha is undetectable in most amniotic fluid samples from patients in the midtrimester of pregnancy and at term not in labor. (2) Microbial invasion of the amniotic cavity is associated with increased concentrations of immunoreactive amniotic fluid macrophage inflammatory protein-1 alpha in both term and preterm gestations. (3) Amniotic fluid macrophage inflammatory protein-1 alpha concentrations significantly correlate with interleukin-8 levels and white blood cell count in amniotic fluid. Our data strongly suggest a role for macrophage inflammatory protein-1 alpha in the mechanisms responsible for the recruitment of leukocytes into the amniotic cavity during the course of intrauterine infection.

Amnion↗

The value of amniotic fluid interleukin-6, white blood cell count, and gram stain in the diagnosis of microbial invasion of the amniotic cavity in patients at term.

PROBLEM: Subclinical microbial invasion of the amniotic cavity occurs in 18.8% of women with term labor and intact membranes and in 34% of patients with term PROM and is a risk factor for the development of puerperal infection related morbidity. Although amniotic fluid white blood cell count, interleukin-6 determination, and Gram stain examination have been used for the diagnosis of intrauterine infection in patients with preterm labor and preterm premature rupture of membranes, no information is available about the accuracy and specific cut-off values for these tests in patients at term. The purpose of this study was to compare the performance of the amniotic fluid Gram stain examination, white blood cell count, and interleukin-6 determination in the identification of microbial invasion of the amniotic cavity in patients at term with and without PROM. METHOD: Amniotic fluid was retrieved from 148 patients with term gestations (90 patients with spontaneous labor and intact membranes and 58 patients with PROM). Samples were cultured for bacteria and Mycoplasma species. Amniotic fluid Gram stain, white blood cell count, and interleukin-6 determinations (ELISA, sensitivity: 43 pg/ml) were performed in all samples. Microbial invasion of the amniotic cavity was defined as a positive amniotic fluid culture for microorganisms. Analysis was conducted using Mann-Whitney U test, Fisher's exact test, receiver operating characteristic curves and logistic regression. RESULTS: Patients with spontaneous labor and intact membranes: The prevalence of microbial invasion of amniotic cavity in this group was 15.6% (14/90). The most sensitive test for the detection of microbial invasion of the amniotic cavity was amniotic fluid interleukin-6 determination (sensitivity for: interleukin-6 > or = 5.7 ng/ml = 86%, white blood cell count > or = 20 cells/mm3 = 64%, Gram stain = 28%). The most specific test was the Gram stain of the amniotic fluid (specificity for: Gram stain = 84%, interleukin-6 = 79% and white blood cell count = 63%). Multiple logistic regression demonstrated that amniotic fluid interleukin-6 concentration was the only covariate that retained statistical significance when intrauterine infection was used as outcome variable. Patients with PROM: The prevalence of a positive amniotic fluid culture in this group was 39.7% (23/58). Logistic regression demonstrated that only interleukin-6 retained a significant relationship with the results of amniotic culture when all variables were entered simultaneously into a model to predict amniotic fluid culture results. The most sensitive tests for the detection of intrauterine infection were interleukin-6 determination and white blood cell count (sensitivity for interleukin-6 > or = 3.4 ng/ml and white blood cell count > or = 20 cells/mm3 = 69.6% for both). The most specific test was Gram stain (97.1%). CONCLUSIONS: Amniotic fluid interleukin-6 determination is the best rapid test for the detection of microbial invasion of the amniotic cavity in patients at term with and without PROM. When this test is not available, amniotic fluid Gram stain and white blood cell count represent valid diagnostic tools to assess the microbial state of amniotic cavity.

Amniotic Fluid↗