Evaluation of the Ryegrass Stem Rust Model STEMRUST_G and Its Implementation as a Decision Aid.

STEMRUST_G, a simulation model for epidemics of stem rust in perennial ryegrass grown to maturity as a seed crop, was validated for use as a heuristic tool and as a decision aid for disease management with fungicides. Multistage validation had been used in model creation by incorporating previously validated submodels for infection, latent period duration, sporulation, fungicide effects, and plant growth. Validation of the complete model was by comparison of model output with observed disease severities in 35 epidemics at nine location-years in the Pacific Northwest of the United States. We judge the model acceptable for its purposes, based on several tests. Graphs of modeled disease progress were generally congruent with plotted disease severity observations. There was negligible average bias in the 570 modeled-versus-observed comparisons across all data, although there was large variance in size of the deviances. Modeled severities were accurate in >80% of the comparisons, where accuracy is defined as the modeled value being within twice the 95% confidence interval of the observed value, within ±1 day of the observation date. An interactive website was created to produce disease estimates by running STEMRUST_G with user-supplied disease scouting information and automated daily weather data inputs from field sites. The model and decision aid supplement disease managers' information by estimating the level of latent (invisible) and expressed disease since the last scouting observation, given season-long weather conditions up to the present, and it estimates effects of fungicides on epidemic development. In additional large-plot experiments conducted in grower fields, the decision aid produced disease management outcomes (management cost and seed yield) as good as or better than the growers' standard practice. In future, STEMRUST_G could be modified to create similar models and decision aids for stem rust of wheat and barley, after additional experiments to determine appropriate parameters for the disease in these small-grain hosts.

Antepartum fetal death following a yellow scorpion sting.

Scorpion envenomation in pregnant victims has been scarcely studied. We would like to suggest an association between yellow scorpion sting during the third trimester of pregnancy and adverse fetal outcome. The particular deleterious mechanism of scorpion venom has not been elucidated yet.

Mullerian inhibiting substance levels at the time of HCG administration in IVF cycles predict both ovarian reserve and embryo morphology.

BACKGROUND: Pre-antral and early antral follicles secrete Müllerian inhibiting substance (MIS), suggesting that MIS may directly reflect ovarian reserve. Since little is known about how ovarian reserve affects oocyte quality, we attempt here to assess the predictive value of MIS on embryo morphology and IVF outcome. To do so, we measured MIS at the time of HCG administration 36 h prior to oocyte retrieval. METHODS: A total of 257 patients undergoing IVF were prospectively recruited. We measured MIS levels by enzyme-linked immunosorbent assay at the time of HCG, and compared the MIS values to day 3 FSH levels in the prediction of embryo morphology and IVF outcome. RESULTS: The distribution of MIS levels was skewed, with a median of 2.7 ng/ml (range 0 to 28.5 ng/ml). MIS values at the time of HCG administration inversely correlated with basal FSH levels (P = 0.002), and both correlated significantly with patient age, number of mature follicles, number of oocytes retrieved and serum estradiol levels. MIS levels correlated significantly with a greater number of 6-cell embryos and better embryo morphology score, while basal FSH levels did not correlate with these outcome variables. MIS levels > or =2.7 ng/ml portended improved oocyte quality as reflected in a higher implantation rate (P = 0.001) and a trend toward a better clinical pregnancy rate (P = 0.084). CONCLUSIONS: MIS levels seem to predict not only ovarian reserve, but also embryo morphology. Measurement of MIS at the time of HCG administration may, therefore, in the future improve management of patients undergoing treatments with assisted reproductive technology.

The reduction of a nitroxide spin label as a probe of human blood antioxidant properties.

The kinetics of reduction of the radical R*, 5-dimethylaminonaphthalene-1-sulfonyl-4-amino-2,2,6,6-tetramethyl-1-piperidine-oxyl by blood and its components were studied using the EPR technique. The results demonstrate that R* is adsorbed to the outer surface of the membrane and does not penetrate into the erythrocytes. A series of control experiments in PBS demonstrate that ascorbate is the only natural reducing agent that reacts with R*. The observed first order rate of disappearance of the nitroxide radical k, is: k(blood) > k(eryth) > k(plasma) and k(blood) approximately = k(eryth) + k(plasma). The results demonstrate that: a. The erythrocytes catalyze the reduction of R* by ascorbate. b. The rate of reduction of the radical is high though it does not penetrate the cells. c. In human erythrocytes there is an efficient electron transfer route through the cell membrane. d. The study points out that R* is a suitable spin label for measuring the reduction kinetics and antioxidant capacity in blood as expressed by reduction by ascorbate.

Post-term pregnancy: should induction of labor be considered before 42 weeks?

OBJECTIVE: To determine the occurrence of maternal and fetal complications in low-risk pregnancies beyond 39 weeks and to re-evaluate the acceptable cut-off (42 weeks) for induction of labor. STUDY DESIGN: A total of 36 160 low-risk pregnancies with reliable dating of gestational age (last menstrual period and early ultrasound examination) were evaluated retrospectively for fetal and maternal complications, including non-progressive labor, cervical tear, retained placenta, postpartum hemorrhage, vacuum delivery, Cesarean section, macrosomia, meconium-stained amniotic fluid, non-reassuring fetal heart rate monitoring and ante-, intra- and postpartum death. Pregnancy outcomes at different gestational ages were compared using univariate and multivariate analysis and receiver operator curves. RESULTS: The rates of non-progressive labor stage I and II, retained placenta, vacuum delivery, Cesarean section, macrosomia, meconium-stained amniotic fluid and non-reassuring fetal heart rate monitoring were found to be significantly higher with increasing gestational age in the univariate analysis. These parameters were evaluated using multivariate analysis and the following were found to be significantly higher: non-progressive labor stage I and II, macrosomia, meconium-stained amniotic fluid and Cesarean section. Statistical analysis (receiver operator curves) showed that the most significant rise in the risk for non-progressive labor occurred after 42 completed weeks of gestation, and after 41 completed weeks for macrosomia, meconium-stained amniotic fluid and Cesarean section. CONCLUSIONS: The rates of non-progressive labor stage I and II, meconium-stained amniotic fluid, macrosomia and Cesarean section were significantly higher with increasing gestational age. In order to decrease the rate of macrosomia, meconium-stained amniotic fluid and Cesarean section, we suggest that induction of labor should be considered before 42 weeks.

Gestational diabetes complicated by hydramnios was not associated with increased risk of perinatal morbidity and mortality.

OBJECTIVE: To determine whether gestational diabetes (GDM) complicated with hydramnios is associated with higher rates of perinatal morbidity and mortality than those with normal amniotic fluid (AFI). STUDY DESIGN: A case control study of 368 pregnant women with GDM was conducted between January 1995 and December 1996. The study group consisted of 184 women with hydramnios (AFI>25 cm) that were matched for maternal age, parity, and gestational age to 184 women with gestational diabetes and normal AFI. A Student's t-test, McNemar test and logistic regression test were used to compare the two groups. RESULTS: Both groups were under strict metabolic control; mean glucose levels of 5.2+/-2.4 mmol/l in the study group and 5.5+/-2.4 mmol/l in the controls (P>0.05). There were no significant differences between groups in the rates of severe preeclampsia, premature rupture of membranes (PROM), cesarean section rate, intrauterine growth restriction (IUGR), antepartum fetal death, fetal distress, prolapse of umbilical cord and placenta abruption. Even though the prevalence of large for gestational age (LGA) and birth weight were significantly higher in the study group (31 versus 19% and 3441+/-477 versus 3232+/-554 g, respectively), the prevalence of neonatal trauma was the same in both groups (2.6%). There was no significant difference in the Apgar scores (1 and 5 min), newborn hypoglycemia, metabolic acidosis and hyperbilirubinemia. CONCLUSIONS: Hydramnios in women with GDM was not associated with increased risk of perinatal morbidity and mortality.

Oxytocin use in grand-multiparous patients: safety and complications.

OBJECTIVE: To determine whether the use of oxytocin for the augmentation of labor in grandmultiparous women increases the risk of peripartum complications. STUDY DESIGN: During the years 1989-97, 11 075 grand-multiparous women delivered at our institution. In 424 grand-multiparous women, intravenous oxytocin was used for augmentation of labor. The control group consisted of the other 10 651 grand-multiparous women. All women were monitored for fetal heart rate and uterine contractions. We compared the rates of maternal and perinatal complications in these two groups by using chi(2) analysis and Fisher's exact test when appropriate. RESULTS: No significant differences were found between the oxytocin and the control groups in the rates of placental abruption, intrapartum fetal death, postpartum hemorrhage, uterine rupture, fetal distress, meconium-stained amniotic fluid, an Apgar score of less than 7 at 5 min, Cesarean section, retained placenta and vaginal and cervical lacerations. In contrast, a significant increase in the rate of vacuum deliveries was observed in patients given oxytocin as compared to controls (3.5% vs. 1.4%, respectively; p = 0.001). CONCLUSIONS: The use of oxytocin in the grand-multiparous parturient was a safe procedure with no significant increase in peripartum complications. However, a higher rate of vacuum deliveries was found.

Failed vacuum extraction. Maternal risk factors and pregnancy outcome.

OBJECTIVE: To evaluate obstetric risk factors associated with a failed trial of vacuum extraction and to assess its pregnancy outcome. STUDY DESIGN: All attempted vacuum extractions between the years 1990 and 1998 were identified, and a comparison of successful and failed trials of vacuum extraction in singleton, vertex deliveries was performed. RESULTS: Of 2,111 trials of vacuum extraction, 113 (5.4%) cases were complicated by failed extraction and underwent cesarean section. Those neonates were significantly more likely to be large for gestational age, specifically to weigh > 4,000 g as compared to the controls. Patients lacking prenatal care had significantly higher rates of failed vacuum extraction trials. While cervical and uterine tears were rather rare, parturients who had failed trials of vacuum extraction had significantly higher rates of cervical and uterine tears as compared to those with successful vacuum extractions. This association remained significant after controlling for a previous cesarean section using the Mantel-Hanszel technique. Women from the failed vacuum extraction group had significantly higher rates of postpartum anemia. Pregnancies complicated by failed vacuum extraction had significantly higher rates of intrapartum and postpartum fetal death. Those neonates had significantly higher rates of Apgar scores < 7 at one and five minutes. CONCLUSION: Failed trial of vacuum extraction is associated with adverse maternal and fetal outcomes. Risk factors associated with such failures are fetal weight and lack of prenatal care. Thus, careful estimation of fetal weight should be performed before the procedure, and estimated fetal weight > 4,000 g might be considered a relative contraindication to vacuum extraction, especially among patients who did not have prenatal care.

Risk factors associated with true knots of the umbilical cord.

OBJECTIVE: To determine obstetrical risk factors and pregnancy outcome of fetuses with true knot of the umbilical cord. METHODS: Study population included 69,139 singleton deliveries occurring between the years 1990-1997. Data were retrieved from the database of the Soroka University Medical Center. Fetuses with malformations were excluded. RESULTS: The incidence of true knots was 1.2% (841/69,139). In a multivariate analysis the following factors were found to be significantly associated with true knot of cord: grandmultiparity, chronic hypertension, hydramnios, patients who undergone genetic amniocentesis, male gender and cord problems (prolapse of cord and cord around the neck). The incidence of fetal distress and meconium stained amniotic fluid was significantly higher among patients with true knots of cord (7% versus 3.6%, P<0.001 and 22% versus 16%, respectively, P<0.0001). Moreover, there was a four-fold higher rate of antepartum fetal death among those fetuses (1.9% versus 0.5%, P<0.0001). In addition, fetuses with true knots of the umbilical cord were more often delivered by a cesarean section (130/841 versus 711/68,298, P<0.0001). The following obstetrical factors were found to be significantly correlated to true knots of the umbilical cord in a multiple logistic regression model: gestational diabetes, hydramnios, patients undergoing genetic amniocentesis, male fetuses. CONCLUSIONS: Patients with hydramnios, who underwent genetic amniocentesis and those carrying male fetuses are at an increased risk for having true knots of the umbilical cord. Thus, careful sonographic and Doppler examinations should be seriously performed in these patients for detection of the complication of the umbilical cord.

The effect of low-molecular weight dextran on erythrocyte aggregation in normal and preeclamptic pregnancy.

Erythrocyte aggregation was determined by a novel method enabling the quantification of the aggregation process in whole blood. Blood samples of 47 healthy pregnant women and 39 preeclamptic patients were examined. Subjects within each group were matched for the gestational age. It was found that RBC aggregation increases with the gestational age in healthy pregnancy and further increases in preeclampsia. Addition of low-molecular weight dextran (MW = 9300) to blood samples of both healthy pregnant women and preeclamptic patients reduces RBC aggregation in a concentration-dependent manner. The obtained results indicate alterations in plasma composition as the primary factor for the increased RBC aggregation in both normal and pathological pregnancy. It is suggested that adsorption of low-molecular weight dextran on the RBC membrane reduces the surface concentration of plasma bridging molecules thereby reducing RBC aggregation toward normal.

Dual distant uterine placental insertion connected by a placental band. A case report.

BACKGROUND: There are several types of intrauterine membranes; most are not associated with any deleterious effect on fetal outcome. CASE: An unusual placental insertion was diagnosed sonographically at 23 weeks of gestation. It consisted of two distant placental insertions into the uterine wall, with a large placental mass between them floating freely in the uterine cavity. Normal fetal growth pattern and blood flow indices were found. A normal female neonate was delivered via low transverse cesarean section. There were no macroscopic or microscopic placental anomalies. CONCLUSION: This case raises several questions: the right mode of delivery, frequency of ultrasound follow-up and possibility of placental band rupture and hemorrhage during vaginal delivery.

Primary hepatoid carcinoma of ovary in pregnancy.

We report a rare case of a 35-year-old woman with primary hepatoid carcinoma of the ovary during pregnancy associated with abnormal levels of maternal serum alpha-fetoprotein. This tumor should be considered in the differential diagnosis of pregnant women with very high levels of maternal serum alpha-fetoprotein whenever other maternal or fetal sources are excluded.

Routine revision of uterine scar after cesarean section: has it ever been necessary?

Although a trial of labor after cesarean section (VBAC) is successful and relatively safe, few studies have directly addressed the necessity of routine transcervical revision of uterine scar after prior cesarean section. We performed a longitudinal study of 3469 women who had VBAC. In all patients, uterine scar integrity was examined immediately after placental expulsion. The detection rate of uterine scar dehiscence or rupture was 0.23% (8/3469). Only one woman with complete uterine rupture needed immediate laparotomy for severe hemorrhage. Out of seven patients (0.2%), who had evidence of uterine dehiscence, three underwent explorative laparotomy. In conclusion, the potential benefit of routine examination of uterine scar after VBAC is doubtful. Transcervical revision should be performed only in symptomatic patients.

Isolated hydramnios at term gestation and the occurrence of peripartum complications.

OBJECTIVE: To determine if hydramnios at term gestation is an independent risk factor for poor pregnancy outcome and perinatal death. STUDY DESIGN: The study population consisted of 60,702 patients with singleton gestation who delivered at term (>37 weeks). Patients were classified into two groups according to the presence or the absence of hydramnios. Hydramnios was diagnosed in the presence of an amniotic fluid index greater than 25 cm or of a maximum vertical pocket of amniotic fluid of at least 8 cm or by subjective assessment. Logistic regression analysis was used to evaluate the unique contribution of hydramnios to fetal death and to perinatal and maternal morbidity. RESULTS: The prevalence of hydramnios was 1211/60,702 (2%). Patients with hydramnios had a higher incidence of complications than those with a normal amount of amniotic fluid: cesarean section (22.8 vs. 8.5%, P<0.01), antepartum death (0.6 vs. 0.2%, P<0.005), postpartum death (2.8 vs. 0.4%, P<0.01), abruptio placenta (0.9 vs. 0.3%, P<0.001), fetal distress (6.1 vs. 3.65%, P<0.0015), meconium-stained amniotic fluid (17.8 vs. 15%, P<0.001), low Apgar score at 5 min (2.95 vs. 1%, P<0.01), malpresentation (6.8 vs. 2.9%, P<0.01), clinical chorioamnionitis (0.3 vs. 0.1%, P<0.05), prolapse of cord (2.2 vs. 0.3%, P<0.01), and large-for-gestational-age infant (LGA) (23.8 vs. 8.1%, P<0.01). When adjusted for confounding variables, the presence of hydramnios remained strongly associated with perinatal mortality (odds ratio 5.5 (95% CI 3.2-9.3)) and neonatal and maternal morbidity (odds ratios 2.1 (CI 1.1-3.7) and 2.3 (CI 1.9-2.7), respectively). CONCLUSIONS: (1) Hydramnios at term is an independent risk factor for perinatal death; (2) Fetal surveillance is warranted in patients with hydramnios even in the absence of other known risk factors for adverse pregnancy outcome.

[Effect of the Yom Kippur fast on parturition].

Food-withdrawal has been proposed as a possible mechanism for initiating the onset of labor in animals and humans. The hypothesis was based upon the reported increase in deliveries of infants during the Yom Kippur fast. We studied the effect of the fast on full term deliveries of Jewish women, with non-fasting Bedouin women as controls (1988-1995, 1,313 Jewish and 1,091 Bedouin deliveries). To determine the effect of Yom Kippur itself, delivery rates on Sukkot and Yom Kippur were compared in both groups. The mean delivery rate in the Jewish population was significantly higher during Yom Kippur and the day after, than during the 7 days before Yom Kippur (15.1 +/- 5.1 and 14.6 +/- 4.7 vs 10.7 +/- 3.5, p < 0.04 and p < 0.01, respectively). There was an increase in delivery rate during the 6 hours before the end of the fast. In the Bedouin women there were no changes in delivery rate during any of these periods. There were no significant differences in the rates of deliveries during the Sukkot festival between Jewish and Bedouin women. We conclude that fasting is associated with a significant increase in the rate of deliveries at term.

Acute and long-term beta-adrenergic blockade for patients with neurocardiogenic syncope.

OBJECTIVES: This study was designed to prospectively evaluate the long-term outcome of drug therapy guided by head-up tilt testing for the management of unexplained syncope and near syncope. BACKGROUND: Head-up tilt testing is used to evaluate patients with unexplained syncope. The validity of acute drug testing and the efficacy of long-term oral therapy for prevention of recurrent syncope have not been investigated in large patient groups. METHODS: We studied 296 consecutive patients with unexplained syncope or near syncope who underwent 80 degrees head-up tilt testing with and without isoproterenol challenge. The efficacy of intravenous and oral beta-blocker therapy was evaluated by repeat testing. Patients with both positive and negative responses to therapy were followed up for rates of recurrence of syncope. RESULTS: A total of 193 patients (65%) had a positive tilt test response; 89% of these 193 required isoproterenol challenge to elicit this response. Patients with a positive tilt test result had lower values for heart rate at rest (mean +/- SD 69 +/- 13 vs. 74 +/- 14 beats/min, p = 0.046) and systolic blood pressure (137 +/- 28 vs. 145 +/- 30 mm Hg, p = 0.0018) at baseline than did the patients with a negative tilt test result. Intravenous propranolol blocked the positive response in 163 (90%) of 181 patients retested. Oral beta-blockers were effective by tilt test criteria in 118 (94%) of 125 patients; 12 (10%) had recurrent clinical symptoms while taking beta-blockers. Eight (42%) of 19 patients who had a negative tilt test response during beta-blocker therapy had recurrent symptoms when they stopped therapy. Three (23%) of 13 patients receiving empiric beta-blocker therapy had recurrent symptoms. The follow-up period for the patients with a positive tilt test result was 28 +/- 11 months (range 5 to 48). CONCLUSIONS: Intravenous propranolol is effective in preventing neurocardiogenic syncope diagnosed during head-up tilt testing and predicts the response to oral beta-blocker therapy. Oral beta-blocker therapy prevents recurrent syncope in the majority of patients. Recurrence of syncope is lowest when efficacy of oral beta-blocker therapy is confirmed by repeat head-up tilt testing.