Search PubMed⌕ Search

Biomedical subjects

L D Platt

Publications and source records attributed to L D Platt.

At least 127 records · Page 7Linked to original sources
PubMed1988

Molecular genetic prenatal determination of twin zygosity.

A method of human identity determination using synthetic oligonucleotide probes was applied to prenatal determinations of twin zygosity. Deoxyribonucleic acid "fingerprints" were obtained from chorionic villi or amniocytes. In all cases, the technique predicted twin zygosity with very small tissue samples. The accuracy and simplicity of the method far exceed those of any other currently used technique. This technique should be applicable in those situations in which prenatal determination of relationship is needed.

Amniotic Fluid↗
PubMed1988

Transrectal ultrasound versus cystography in the evaluation of anatomical stress urinary incontinence.

Thirty-two female patients with clinical and urodynamic findings of genuine stress urinary incontinence were evaluated before and 6 months after surgery for stress urinary incontinence. Twenty-nine control patients had identical evaluations before and 6 months after surgery which did not involve the urethrovesical junction. Twenty-four patients with primary bladder instability had similar evaluations and served as a second control group. Anatomical landmarks indicating support to the urethrovesical junction were evaluated by the position of the urethra at the most dependent point in the bladder on straining and the urethral descent on straining to beneath the posterior ramus of the symphysis pubis on bead chain cystography. The urethrovesical junction drop on straining was evaluated by transrectal ultrasonography. Cystographic and ultrasonographic tests for the position of the urethrovesical junction at the most dependent position in the bladder during straining were very sensitive in women with stress urinary incontinence (94 and 87% respectively) but much less specific (45 and 48% respectively). When evaluating anatomical support to the urethrovesical junction and its descent on straining, these tests were both highly sensitive (97 and 94% respectively) and specific (76 and 96% respectively) in women with genuine stress urinary incontinence. Simple clinical tests for support of the urethrovesical junction, such as the Q tip test, are non-specific in patients with stress urinary incontinence. Transrectal ultrasonography is a simple and quick out-patient procedure. The availability of ultrasound equipment in most clinics and the high sensitivity and specificity of the test make it an attractive and cost-effective alternative to X-ray cystography in the pre-operative evaluation of anatomical support to the urethrovesical junction.

Adult↗
PubMed1988

Ultrasonic prediction of stress urinary incontinence development in surgery for severe pelvic relaxation.

Forty-six patients with a third-degree cystocele with no complaints of genuine stress urinary incontinence underwent complete urodynamic evaluation including ultrasonic evaluation before and 3 months postoperatively. Ultrasound examination was able to predict in 46 patients those requiring urethropexy surgery for support of their bladder base (n = 22). The 24 patients with good bladder base support by ultrasound did not develop genuine stress urinary incontinence. The use of ultrasound in women with third-degree cystocele appears to predict which patients will require urethropexy surgery in addition to their cystocele repair.

Adult↗
PubMed1988

Fetal umbilical velocimetry using continuous-wave and pulsed-wave Doppler ultrasound in high-risk pregnancies: a comparison of systolic to diastolic ratios.

Systolic to diastolic (S/D) ratios of umbilical velocimetry using either continuous-wave or pulsed-wave Doppler ultrasound have been used to assess downstream placental resistance. The purpose of this study was to compare the S/D ratios obtained by both types of instrumentation to determine whether there are significant differences between measurement values. Umbilical velocimetry was performed on 200 high-risk pregnancies in the third trimester using the Angioscan III to obtain continuous-wave velocimetry and the General Electric RT3600 to obtain pulsed-wave velocimetry. Systolic to diastolic ratios were considered abnormally high if they were greater than 3. One hundred sixty-five patients had normal S/D ratios and 35 patients had elevated ratios on both continuous-wave and pulsed-wave ultrasound. There was no significant difference in the mean S/D ratios obtained by either method for the entire population (continuous-wave S/D 2.81 +/- 1.79, pulsed-wave S/D 2.71 +/- 1.83, R = 0.98), the normal group (continuous-wave S/D 1.96 +/- 0.41, pulsed-wave S/D 1.95 +/- 0.40, R = 0.91), and the abnormal group (continuous-wave S/D 6.23 +/- 1.58, pulsed-wave S/D 6.35 +/- 1.52, R = 0.94). Least-square regression was performed to model the relationships between pulsed wave and continuous wave, with both used as dependent variables. The slopes and intercept for the normal and abnormal groups were evaluated and were significantly different (P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
PubMed1988

Fetal umbilical velocimetry for the surveillance of pregnancies complicated by placenta previa.

Continuous-wave Doppler studies of the umbilical arteries were performed on 100 women with placenta previa prior to delivery in the third trimester and 100 control subjects matched for gestational age and with normally implanted placentas. The ratio of the maximum (systole [S]) and minimum (diastole [D]) velocities appeared to reflect downstream vascular resistance. An S:D ratio of greater than or equal to 3.0 indicated elevation. There was a statistically higher S:D ratio in the placenta previa group as compared to the control group, and that difference persisted even when growth-retarded fetuses were excluded from both groups. Placenta previa patients with S:D ratios greater than or equal to 3.0 were associated with a statistically higher incidence of adverse pregnancy outcomes. The sensitivity, specificity, and positive and negative predictive value of an elevated S:D ratio in predicting adverse pregnancy outcomes were 90.0%, 93.8%, 62.0% and 98.5%, respectively. Our data suggest that (1) placenta previa patients are at increased risk of intrauterine growth retardation and adverse pregnancy outcomes, (2) placenta previa patients with normal S:D ratios are at no greater risk of adverse outcomes than are controls, (3) when the S:D ratio is elevated in placenta previa patients, it is more likely to be associated with adverse pregnancy outcomes, and (4) placenta previa patients without growth failure have a higher S:D ratio than do those with normally implanted placentas. Umbilical artery velocimetry appears to be a useful adjunct to ultrasound in the surveillance of pregnancies complicated by placenta previa.

Adult↗
PubMed1988

Incidental adnexal neoplasms at cesarean section.

A 10-year retrospective review was conducted of incidental adnexal neoplasms found at the time of cesarean section. During the 10-year period between July 1, 1976 and June 30, 1986, 17,902 cesarean sections were performed at Women's Hospital of the Los Angeles County/University of Southern California Medical Center. Adnexal neoplasms were identified with an incidence of one neoplasm per 197 cesarean sections. When a neoplasm is discovered during surgery, conservative surgery is recommended.

Adnexal Diseases↗
PubMed1988

Maternal and fetal blood flow velocity waveforms in patients with preterm labor: effect of tocolytics.

The effect of tocolytics on systolic to diastolic (S/D) ratios used to assess downstream vascular resistance and obtained from umbilical and uterine velocity waveforms has not been studied to date. Continuous-wave Doppler studies were performed on the umbilical and uterine arteries of 60 consecutive patients with the diagnosis of preterm labor. Forty patients receiving intravenous magnesium sulfate and 20 patients receiving intravenous ritodrine tocolysis underwent Doppler studies before therapy, during incremental therapy, and four hours post-therapy. There was a statistically significant (P less than .001) progressive decrease in the uterine and umbilical S/D ratios along with a concomitant increase in maternal and fetal heart rate associated with increasing infusion doses of ritodrine. Both the S/D ratios and heart rates returned to pretherapy range four hours after discontinuing therapy. Magnesium sulfate tocolysis was not associated with any significant change in S/D ratios or maternal and fetal heart rate. We conclude that intravenous ritodrine affects umbilical and uterine vascular resistance as measured by S/D ratios. This response may be secondary to changes in maternal and fetal heart rate.

Adult↗
PubMed1988

Fetal foot length: relationship to menstrual age and fetal measurements in the second trimester.

The purpose of this study was to describe the ultrasonic measurement of fetal foot length and to develop mathematical models to quantify the relationships between menstrual age and commonly measured fetal structures. We evaluated 120 patients with known last menstrual periods and normal pregnancies to develop a cross-sectional study population. All patients had ultrasonic measurement of the fetal foot length, biparietal diameter, head circumference, abdominal circumference, and femur length. Least-squares estimation of linear models was used to select the best mathematical models to describe the relationship between menstrual age and fetal foot length. A similar evaluation of the relationship between fetal foot length and the other measured parameters was performed. All models were best described by a linear equation. An R2 value of 0.94, with a standard error of the estimate of 0.204, was obtained for menstrual age versus fetal foot length. When the model for fetal foot length and menstrual age was compared with published anatomical data, close agreement was seen over the time interval studied. Our results suggest that the measurement of fetal foot length with ultrasound gives a reliable assessment of anatomical fetal or neonatal foot length and is highly correlated to the menstrual age of the fetus.

Female↗
PubMed1987

Fetal echocardiography: the prenatal diagnosis of tricuspid atresia (type Ic) during the second trimester of pregnancy.

Fetal echocardiography (real-time and M-mode) was used to evaluate a fetus at 20 weeks of gestation because intermittent bradycardia had been auscultated at 14 weeks of gestation. Real-time examination of the four-chamber view suggested ventricular disproportion with the left ventricle larger than the right, absence of the tricuspid valve, atrial and ventricular septal defects, and normal pulmonic and aortic outflow tracts. M-mode quantitation demonstrated a dilated left ventricle, small right ventricle, dilated mitral valve, hypertrophy of the left ventricular wall, and normal outflow tract dimensions. Following the diagnosis of tricuspid atresia (type Ic), genetic amniocentesis was performed (46,XX). Intrauterine death occurred during the 28th week of gestation. Autopsy confirmed the echocardiographic findings.

Echocardiography↗
PubMed1987

Prenatal diagnosis of tuberous sclerosis: the use of fetal echocardiography.

Fetal echocardiography was used to identify a cardiac rhabdomyoma in the second trimester. The combination of this finding with a maternal history of Tuberous Sclerosis allowed the patient and her family to make a more educated decision regarding termination of the pregnancy. Post mortem examination of the fetus confirmed the prenatal findings. This case report demonstrates the importance of ultrasound evaluation of the fetus at risk of recurrence of a genetic syndrome in which one or more anatomical defects might be seen.

Adolescent↗
PubMed1987

Fifteen years of experience with antepartum fetal testing.

The introduction of antepartum fetal heart rate testing occurred in the very early 1970s. This article describes the evolution of testing within the Los Angeles County/University of Southern California Medical Center and encompasses a 15-year time period between 1971 and 1985. During this time approximately 200,000 patients were delivered of their infants. Fetal surveillance increased from less than 1% to current levels of 16% of patients. The antepartum fetal death rate was evaluated as a measure of evaluating the usefulness of antepartum testing. The fetal death rate after antepartum testing in selected high-risk patients was significantly less than that found in those patients not tested. The questions that might be raised regarding broader application of this technique and potential benefits are stated.

California↗
PubMed1987

Fetal echocardiography. VII. Doppler color flow mapping: a new technique for the diagnosis of congenital heart disease.

One of the difficulties for the fetal sonographer is the complete elucidation of structural defects of the cardiovascular system that are associated with intracardiac or great vessel flow disturbances. With the recent introduction of Doppler color flow mapping, in which blood flow is displayed in color superimposed on a real-time image, it has been impossible to identify flow disturbances in the pediatric and adult patient. This study was undertaken to determine whether Doppler color flow mapping could be used in the fetus to identify normal and abnormal cardiovascular anatomy. Thirty-five normal and high-risk fetuses were examined between 16 and 40 weeks of gestation. Doppler color flow mapping identified normal and abnormal anatomy (ventricular septal defect, atrial septal defect, endocardial fibroelastosis, dysplastic pulmonary valve, and tricuspid regurgitation). It appears that Doppler color flow mapping will add a new dimension to fetal cardiovascular imaging.

Adult↗
PubMed1987

Antepartum fetal surveillance: the biophysical profile.

In summary, it appears, based on a cumulative experience of more than 15,000 patients from several centers, that fetal biophysical profile scoring holds promise as an improved method of fetal risk detection. Antepartum detection, classification, determination of severity, and ultimately, treatment of the fetus at risk for death and damage in utero form the basis of modern perinatal medicine. It remains to be determined whether addition of further variables or refinement of existing variables will improve accuracy still further. The assessment of multiple biophysical variables and responses to intrinsic and extrinsic stimuli is helpful in differentiating a normal sleeping fetus from an asphyxiated one.

Female↗
PubMed1987

Diagnosis of intrauterine growth retardation: the use of sequential measurements of fetal growth parameters.

Given the current widespread use of diagnostic ultrasound, it is important to identify exactly what information is desirable during the examination. Although dating the pregnancy might be the reason for the initial evaluation, it is important to examine the fetus for structural malformations as well. Both can be accomplished with a second-trimester scan. Once the pregnancy is accurately dated, subsequent measurements of the head, abdomen, and femur should be plotted on growth curves in relation to the age of the fetus, based on the earlier ultrasound examination. The patient should not be related with subsequent examinations. If asymmetric growth failure occurs, then intervention or maternal bed rest should be considered. Intervention should be considered in the presence of abnormal antepartum testing and when fetal growth has arrested following the institution of maternal bed rest. If symmetric IUGR is present, careful evaluation of the fetus for structural malformations and an abnormal karyotype should be considered.

Adult↗
PubMed1987

Clinical utility of the nonstress test in the conservative management of women with preterm spontaneous premature rupture of the membranes.

Preterm spontaneous premature rupture of the membranes (SPROM) is responsible for significant perinatal morbidity and mortality, largely related to prematurity. Consequently, conservative management is frequently elected. These pregnancies, however, are still at risk. Antepartum fetal heart rate testing has been of demonstrable value in other high-risk pregnancies and should offer a method of assessing risk in SPROM. Therefore, a retrospective analysis of patients with SPROM who underwent antepartum fetal heart rate testing was undertaken to evaluate its clinical utility in identifying the fetus at risk. Forty-eight patients underwent 154 nonstress tests in the study population. Indications for delivery included fetal pulmonary maturity, amnionitis and persistent variable decelerations with the failure of amniotic fluid to reaccumulate. Variable decelerations were present in 32% of all tests. Fetal heart rate abnormalities severe enough to warrant delivery were noted in 10 of 48 patients (21%). No intrauterine deaths occurred. Our data suggest that once conservative management is elected in preterm patients with SPROM, the nonstress test may identify fetuses at risk of repeated umbilical cord compression and may allow continuous monitoring or delivery.

Adult↗
PubMed1986

Fetal acoustic stimulation testing. II. A randomized clinical comparison with the nonstress test.

Antepartum fetal heart rate testing, specifically the nonstress test, is of accepted value in the antenatal surveillance of high-risk pregnancies. Fetal rest-activity cycles coupled with arbitrary test intervals appear to lead to falsely nonreactive tests. Methods to alter fetal behavioral states have not been uniformly successful. A retrospective analysis of the adjunctive use of acoustic stimulation at our institution demonstrated a 50% reduction in the number of nonreactive tests. Consequently a prospective randomized clinical trial was undertaken to compare the standard nonstress test with the fetal acoustic stimulation test. Those patients randomized to the fetal acoustic stimulation test underwent transabdominal acoustic stimulation with a Model 5C electronic artificial larynx. The incidence of nonreactive tests was 14% in the control group and 9% in the study group (chi 2 = 11.09, p = 0.004). A significant reduction in testing time was also observed. The fetal acoustic stimulation test offers advantages over the traditional nonstress test by lowering the incidence of nonreactive tests and reducing testing time.

Acoustic Stimulation↗