Faculty Bibliography

Continuous observations, such as reaction and run times, and binary observations, such as correct/incorrect responses, are recorded routinely in behavioral learning experiments. Although both types of performance measures are often recorded simultaneously, the two have not been used in combination to evaluate learning. We present a state-space model of learning in which the observation process has simultaneously recorded continuous and binary measures of performance. We use these performance measures simultaneously to estimate the model parameters and the unobserved cognitive state process by maximum likelihood using an approximate expectation maximization (EM) algorithm. We introduce the concept of a reaction-time curve and reformulate our previous definitions of the learning curve, the ideal observer curve, the learning trial and between-trial comparisons of performance in terms of the new model. We illustrate the properties of the new model in an analysis of a simulated learning experiment. In the simulated data analysis, simultaneous use of the two measures of performance provided more credible and accurate estimates of the learning than either measure analyzed separately. We also analyze two actual learning experiments in which the performance of rats and of monkeys was tracked across trials by simultaneously recorded reaction and run times and the correct and incorrect responses. In the analysis of the actual experiments, our algorithm gave a straightforward, efficient way to characterize learning by combining continuous and binary measures of performance. This analysis paradigm has implications for characterizing learning and for the more general problem of combining different data types to characterize the properties of a neural system.

OBJECTIVE: The objective of the study was to determine the relationship between fetal fibronectin (fFN) testing prior to ultrasound-indicated cerclage and obstetric outcome. STUDY DESIGN: Singleton pregnancies between 18 and 24 weeks' gestation with an ultrasound-diagnosed short cervix (< 25 mm) and funneling (> 25%) of the chorioamniotic membranes into the endocervical canal were analyzed. The fFN testing was performed and patients were randomized to cerclage or no-cerclage. Groups were stratified by fFN result. Cerclage patients were compared with no-cerclage patients. The primary outcome was delivery prior to 35 weeks' gestation. RESULTS: Spontaneous preterm birth prior to 35 weeks' gestation occurred in 15 (44.1%) fFN-positive-cerclage patients and 16 (55.2%) fFN-positive no-cerclage patients (P = .45). Similarly, it occurred in 16 (17.8%) fFN-negative cerclage patients and 11 (17%) fFN-no-cerclage patients (P = .99). CONCLUSION: fFN did not identify optimal candidates for cerclage. However, fFN testing before an ultrasound-indicated cerclage aids in counseling patients, anticipating the outcome of pregnancies complicated by cervical shortening

Continuous (reaction times) and binary (correct/ incorrect responses) measures of performance are routinely recorded to track the dynamics of a subject's cognitive state during a learning experiment. Current analyses of experimental data from learning studies do not consider the two performance measures together and do not use the concept of the cognitive state formally to design statistical methods. We develop a mixed filter algorithm to estimate the cognitive state modeled as a linear stochastic dynamical system from simultaneously recorded continuous and binary measures of performance. The mixed filter algorithm has the Kalman filter and the more recently developed recursive filtering algorithm for binary processes as special cases. In the analysis of a simulated learning experiment the mixed filter algorithm provided a more accurate and precise estimate of the cognitive state process than either the Kalman or binary filter alone. In the analysis of an actual learning experiment in which a monkey's performance was tracked by its series of reaction times, and correct and incorrect responses, the mixed filter gave a more complete description of the learning process than either the Kalman or binary filter. These results establish the feasibility of estimating cognitive state from simultaneously recorded continuous and binary performance measures and suggest a way to make practical use of concepts from learning theory in the design of statistical methods for the analysis of data from learning experiments.

BACKGROUND: Postpartum ovarian vein thrombosis is a rare diagnosis with a significant associated risk of pulmonary embolism. The mainstay of therapy consists of intravenous antibiotics and anticoagulation. CASE: A 30-year-old woman presented with fever and abdominal pain 3 days after cesarean section and was found to have an ovarian vein thrombosis on computed tomography. Given her history of cerebral arteriovenous malformation and the attendant risk for cerebral hemorrhage with the use of anticoagulation, she was successfully treated with a removable suprarenal inferior vena cava (IVC) filter and intravenous antibiotics. CONCLUSION: For patients who fail to respond to anticoagulation alone or in whom anticoagulation is contraindicated, placement of a retrievable suprarenal IVC filter is a viable treatment option in the setting of postpartum ovarian vein thrombosis

OBJECTIVE: Discussion of isolated ultrasound (US) markers for fetal aneuploidy can provoke significant patient anxiety. The objective of this study is to quantify maternal anxiety associated with the detection of these markers. METHODS: All patients undergoing routine second-trimester US examination for fetal anatomical survey over a one-year period were administered the State-Trait Anxiety Inventory (STAI) for Adults before and after the procedure. Women with isolated fetal markers for aneuploidy were notified of the findings but discouraged from pursuing amniocentesis. Rates of normal US examination, aneuploidy markers, anomalies, amniocentesis, and pregnancy outcomes were assessed across the ethnic groups. Pre- and post-ultrasound STAI surveys were scored and standardized with previously established norms. Student t-tests, Chi-square, and analysis of variance (ANOVA) were used where appropriate. RESULTS: Among the 798 patients tested, 57% were Hispanic, 30% were Asian, 6% were Black, and 7% were White. Maternal anxiety level was decreased in women after a normal US. The anxiety level increased with aneuploidy markers and was the highest with anomalies. Aneuploidy markers were more common among Hispanic and Asian fetuses, without any associated aneuploidy. Women with isolated aneuploidy markers underwent amniocentesis as often as women with advanced maternal age. CONCLUSION: The detection and communication of isolated aneuploidy markers is associated with increased maternal anxiety and unnecessary amniocentesis

OBJECTIVE: The objective of this study was to determine the effect of omega-3 fatty acids (eicosapentaenoic acid [EPA]; docosahexaenoic acid [DHA]) on prostaglandin production and prostanoid enzyme expression in cultured decidual cells exposed to interleukin-1beta (IL-1beta), a cytokine that plays a major role in inflammation. STUDY DESIGN: Decidua was obtained from human placentas of nonlaboring patients at term cesarean delivery (N = 6) and cultured by using standard cell culture techniques. Cells were preincubated in defined media with various concentrations of vehicle, DHA, or EPA for 1 hour. IL-1beta (10 ng/mL) was then added to the media, and experiments were terminated 12 hours after exposure to IL-1beta. Prostaglandin E2 (PGE2) and PGF2alpha concentrations in conditioned media were measured by enzyme-linked immunosorbent assay; cyclooxygenase-1 (COX-1), COX-2, microsomal prostaglandin E synthase (mPGES)-1, mPGES-2, and 15-hydroxy prostaglandin dehydrogenase (PGDH) expression were quantified by real-time polymerase chain reaction and immunoblotting. Groups were compared with the use of Student t test, with significance defined as P < .05. RESULTS: Preincubation with DHA decreased prostaglandin production by up to 80% when compared with controls. DHA decreased both mPGES-1 and -2 messenger RNA expression by approximately 50% (P = .02). Preincubation in DHA or EPA had no effect on COX-1, COX-2, and PGDH messenger RNA or protein expression. CONCLUSION: Under conditions simulating inflammation, supplementation with omega-3 fatty acids decreases PGE2 and PGF2alpha production in cultured decidual cells. The reduction in prostaglandin production was associated with a decreased expression of mPGES-1 and -2. These findings suggest a mechanism by which omega-3 fatty acid supplementation decreases the incidence of preterm birth in high-risk patients

OBJECTIVE: The purpose of this study was to determine if prophylactic cerclage improves pregnancy outcome in women with triplet pregnancies without a history of cervical insufficiency. STUDY DESIGN: Triplet pregnancies with > or = 1 day of outpatient surveillance beginning before 32 weeks' gestation were identified from a database of women in the US who received outpatient preterm labor surveillance services between January 1990 and May 2004. Triplet pregnancies managed with prophylactic cerclage were compared with triplet pregnancies in which cerclage was not placed. Patients with a diagnosis of cervical insufficiency in a previous or in the index pregnancy were excluded from analysis. The primary outcome was incidence of preterm birth before 32 weeks. Groups were compared using Fisher exact test, and Student t test with 2-sided P values < .05 considered statistically significant. RESULTS: Three thousand two hundred seventy-eight triplet pregnancies met criteria for inclusion, of which 248 women (7.6%) received prophylactic cerclage. No significant differences were seen in mean gestational age at delivery, incidence of preterm birth before 32 weeks, birth weight, or neonatal days in the hospital. This study had 80% power to detect a 30% reduction in the primary outcome. CONCLUSION: Prophylactic cerclage did not result in improved pregnancy or neonatal outcomes in triplet pregnancies without a history of cervical insufficiency

OBJECTIVE: The purpose of this study was to determine the efficacy of sonographically indicated cerclage in multiple gestations with sonographic evidence of short cervical length (CL). METHODS: Between 1996 and 2002, all multiple gestations undergoing serial CL determinations in the second trimester were identified in 2 separate institutions. Cervical lengths were measured sonographically with transvaginal probes (4-8 MHz). Short CL was defined as a closed CL of 2.5 cm or less. When a short CL was identified before 24 weeks, the study group underwent sonographically indicated cerclage via the modified Shirodkar technique; control patients were placed on bed rest without surgical intervention. The primary outcome was incidence of spontaneous preterm birth before 32 weeks. The groups were compared with the Mann-Whitney U test and the Fisher exact test, with a 2-sided P < .05 used to define statistical significance. Odds ratios were calculated, and 95% confidence intervals were reported. RESULTS: A total of 414 sets of twin gestations and 92 sets of triplet gestations were identified. The median gestational age at delivery for twin gestations was 34.0 weeks for patients who received cervical cerclage and 34.4 weeks for patients with short cervix and no cerclage (P = .77). The median gestational age at delivery for triplet gestations was 34.1 weeks for patients who received cervical cerclage and 33.0 weeks for patients with short cervix and no cerclage (P = .21). There was no difference in the rate of spontaneous preterm delivery at fewer than 28, 30, 32, and 34 weeks or in the rate of preterm premature ruptured membranes. CONCLUSIONS: In our study of multiple gestations with short CL, sonographically indicated cerclage was not associated with a lower incidence of spontaneous preterm delivery compared with conservative management

Ultrasound has an important role not only in assessing amnionicity and chorionicity but also in diagnosing abnormalities and providing fetal surveillance throughout the duration of gestation