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Biomedical subjects

N Kadar

Publications and source records attributed to N Kadar.

At least 73 records · Page 4Linked to original sources
PubMed1987

Infection and labor: the detection of endotoxin in amniotic fluid.

Intra-amniotic infections are frequently caused by gram-negative organisms. Lipopolysaccharide, or endotoxin, is a component of the cell wall of these bacteria. The Limulus amebocyte lysate assay is the most sensitive test clinically available for the detection of endotoxin in biologic samples. The diagnostic value of the Limulus amebocyte lysate assay test for the detection of intra-amniotic infection has been examined and compared with that of the Gram stain. The Gram stain had a 60.8% sensitivity and 9.6% false positive rate. The Limulus amebocyte lysate assay had a 69% sensitivity and a 4.8% false positive rate. When both tests were used in combination, the sensitivity improved to 95.6%, whereas the false positive rate was 14.3%. The Limulus amebocyte lysate assay test is a rapid, sensitive, inexpensive, and simple test for the detection of gram-negative intra-amniotic infections.

Amniotic Fluid↗
PubMed1987

Observations on the log human chorionic gonadotropin-time relationship in early pregnancy and its practical implications.

In this study, we examined whether the doubling time of human chorionic gonadotropin is different at different stages of early pregnancy and whether the use of multiple nomograms for doubling time of human chorionic gonadotropin rather than a single critical value can improve the diagnosis of ectopic pregnancy. Forty-four women with intrauterine pregnancies who had abdominal pain and/or vaginal bleeding but who did not abort their pregnancies and 44 women with surgically proved ectopic pregnancies were studied. No difference was found in the doubling time of human chorionic gonadotropin when women were classified according to recently published criteria (Pittaway DE, Reish RL, Wentz AC. Doubling times of human chorionic gonadotropin increase in early viable intrauterine pregnancies. Am J Obstet gynecol 1985;152:299-302), and estimates of the doubling time of human chorionic gonadotropin were not influenced by the initial human chorionic gonadotropin values or the sampling interval used. In the human chorionic gonadotropin range of practical interest, multiple nomograms identified 26 of 33 (79%) women with ectopic pregnancy who had rising levels of human chorionic gonadotropin, whereas our previously reported criteria identified 28 of 37 (76%) cases. The false positive rate for each method was 9.7%. Seventeen (19%) of 88 patients could not be allotted to the human chorionic gonadotropin categories for which nomograms of the doubling time of human chorionic gonadotropin have been derived. We conclude that our previous recommendations for determining the rate of increase of human chorionic gonadotropin in serum from paired samples do not require revision at this time.

Chorionic Gonadotropin↗
PubMed1987

Do blood and meconium affect the detection of endotoxin in amniotic fluid with the limulus amebocyte gel clot assay?

The limulus amebocyte lysate (LAL), assay is the most sensitive technique for the detection of endotoxin in biological fluids. Because endotoxin is a component of gram-negative bacteria, the assay has been employed in the detection of gram-negative bacterial contamination of biological fluids. The LAL assay is rapid, inexpensive, easy to perform, and requires little laboratory expertise. When used in conjunction with the gram stain examination of amniotic fluid, it improves the detection of intra-amniotic infection before the availability of culture results. However, the usefulness of the LAL assay in the detection of endotoxin in other body fluids is limited by the presence of an inhibitor to the gelation of the assay. The studies reported in this communication were undertaken to establish if amniotic fluid contains such an inhibitor. Sterile amniotic fluid (AF) samples obtained from 93 patients by transabdominal amniocentesis before labor were used to determine the ED 50 dose of endotoxin necessary for a positive LAL result. The ED 50 dose of endotoxin required for gelation was significantly higher when AF--rather than pyrogen-free saline--was used as the diluent, implying that inhibitors are in fact present (ED 50 = 58.3 pgm/ml). The presence of blood or meconium in the AF did not enhance inhibition significantly: ED 50 doses were 58.3 pgm/ml and 56.2 pgm/ml, respectively. This is not significantly different from the ED 50 of clear amniotic fluid.

Amniotic Fluid↗
PubMed1987

Failure of endotoxin to cross the chorioamniotic membranes in vitro.

We have previously reported the detection of endotoxin in the amniotic fluid of patients with gram-negative intra-amniotic infection. Endotoxin or lipopolysaccharide (LPS) is a potent biologic product capable of inducing prostaglandin release from several cell types, and therefore may be involved in the onset of human parturition in the setting of intra-amniotic infection. The experiments outlined in this report were designed to determine whether endotoxin crosses chorioamniotic membranes in vitro. Chorioamniotic membranes obtained at the time of elective cesarean section were placed in Ussing chambers used for transport experiments. Endotoxin was placed in one chamber, and serial timed samples were taken from both chambers for endotoxin quantification, which was performed with the limulus amebocyte gel clot assay. Blue dextran was used to exclude the presence of large defects. Bromophenol blue was used to demonstrate membrane permeability to low-molecular weight substances. Endotoxin failed to cross the chorioamniotic membranes in all experiments (n = 11).

Amnion↗
PubMed1986

The value of serial human chorionic gonadotropin testing as a diagnostic tool in ectopic pregnancy.

This study examines the sensitivity of serial human chorionic gonadotropin determinations in the detection of ectopic pregnancy for patients who present with human chorionic gonadotropin titers less than 6500 mIU/ml. A log human chorionic gonadotropin time curve was used to calculate the slope of change. A slope below 0.11 (85% confidence limit for intrauterine gestations) is used as the cutoff value. Of 50 patients with serial titers at sampling intervals of 2 to 5 days, 26 (49%) had falling values and 22 had subnormal slopes. Only five had initially normal slopes and two of these patients eventually had falling titers. The sensitivity of an abnormal slope (below 0.11) in the detection of ectopic pregnancy was 90%. A 12.5% false positive rate was found in a group of 24 intrauterine pregnancies.

Chorionic Gonadotropin↗
PubMed1986

Estimating the probability of spontaneous delivery conditional on time spent in the second stage.

The duration of second stage labour was studied, retrospectively, among 410 primigravidas who received epidural analgesia in the first stage of spontaneous labour at term (greater than 37 weeks). Survival analysis was used to investigate how the likelihood of a spontaneous delivery was related to time spent in the second stage, and how some maternal and fetal factors influenced this relationship. The proportion of spontaneous deliveries that had occurred by any given time was greatly influenced by maternal age and infant birthweight. However, the women who were least likely to have been delivered by any given time after full dilatation, were also the ones who were least likely to be delivered within any given subsequent time interval. If delivery had not occurred by 3 h, the probability that it would take place in the next 3 h was well under 30% in most cases. We conclude that second stage labour in excess of 3 h is likely to be beneficial only if certain criteria, which are defined in the paper, are met.

Adult↗
PubMed1985

The effect of different human chorionic gonadotropin assay sensitivity on screening for ectopic pregnancy.

The distribution of human chorionic gonadotropin levels in 184 patients with ectopic pregnancy is examined. The impact of changing the sensitivity of human chorionic gonadotropin testing on the incidence of false negative results is discussed. Pregnancy blood tests with a detection threshold of 200 mIU/ml were associated with an 11.9% incidence of false negative results.

Chorionic Gonadotropin↗
PubMed1985

New criteria for the diagnosis of gestational trophoblastic disease.

The purpose of the study was to test the hypothesis of whether the combined use of ultrasound and human chorionic gonadotropin (hCG) determinations could increase the diagnostic accuracy of sonography in the diagnosis of hydatidiform mole. The criteria used were the absence of fetal heart movement by ultrasound when the hCG level was above 82,350 mIU/mL and the presence of an hCG level in excess of 2 SD above the mean for the biometrically derived gestational age for suspected partial moles. The threshold of 82,350 mIU/mL was derived by probit analysis of the hCG serum levels of a population of normal intrauterine pregnancies prospectively examined to determine the level of hCG at which fetal heart activity would be visible by sonography. The diagnostic accuracy of these criteria was compared with the preoperative sonographic examination in 36 hydatidiform moles. When sonography was used alone, 15 of 36 cases (41.6%) did not have a definitive diagnosis on the first examination. The combination of hCG and ultrasound would have correctly identified 32 of the 36 cases (88.8%). This improvement was statistically significant (P less than .005).

Abortion, Missed↗
PubMed1985

Ultrasound assessment of the postmature pregnancy.

The use of ultrasound to identify the fetus at risk for postmaturity among postterm pregnancies was evaluated. The ultrasound findings in 85 postterm pregnancies were reviewed. No grade 0 or grade 1 placentas were observed and grade 2 and 3 placentas were found with similar frequency. The incidence of advanced postmaturity was 12.9%. Advanced postmaturity was found with grade 2 and 3 placentas. Oligohydramnios was very common (81.8%) among pregnancies resulting in postmaturity. The neonatal ponderal index was higher with grade 2 placentas than with grade 3 placentas. The presence of immature placentas (grade 0 or 1) is rare after 42 weeks of gestation. Placental grading cannot be used to predict postmaturity.

Adolescent↗
PubMed1985

Diagnosis of ectopic pregnancy: value of the discriminatory human chorionic gonadotropin zone.

A prospective study was conducted to test the hypothesis that the absence of an intrauterine gestational sac when the serum level of human chorionic gonadotropin (hCG) is above 6500 mIU/mL is indicative of ectopic pregnancy. A total of 383 patients who were clinically suspected to have ectopic pregnancies had pelvic ultrasound examinations with serum hCG determinations on the day of the scan. There were 217 (57%) intrauterine gestations, 104 (27%) ectopic pregnancies, and 62 (16%) spontaneous abortions. Forty-one percent of patients had an hCG level above 6500 mIU/mL. The absence of an intrauterine gestational sac at an hCG concentration above this level had a sensitivity of 100%, a specificity of 96%, a positive predictive value of 86%, a negative predictive value of 100%, and was 98% efficient, based on a 19.4% prevalence of ectopic pregnancies among this group.

Abortion, Spontaneous↗
PubMed1985

Value of culdocentesis in the diagnosis of ectopic pregnancy.

The diagnostic value of culdocentesis was examined in all patients admitted with hemoperitoneum during a three-year period. There was a total of 158 women with positive culdocentesis, of whom 132 (83.5%) had tubal ectopic pregnancies and 26 had other diagnoses. Of the 132 patients with ectopic gestations, the majority (62%) had unruptured tubes. A nondiagnostic culdocentesis should not be used either to raise or to lower the clinician's suspicion of ectopic pregnancy as 16% of patients with an ectopic pregnancy had a nondiagnostic culdocentesis, of which one-quarter were ruptured and three-quarters had hemoperitoneum diagnosed at the time of surgery. A positive culdocentesis along with a positive serum human chorionic assay was associated with an ectopic pregnancy in 99.2% of cases. This procedure should not be limited to the evaluation of patients with classic peritoneal signs, as 45% of the authors' patients with a positive culdocentesis did not have such findings.

Biopsy, Needle↗