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Biomedical subjects

L D Platt

Publications and source records attributed to L D Platt.

At least 37 records · Page 2Linked to original sources
PubMed2000

Femur length and trisomy 21: impact of gestational age on screening efficiency.

OBJECTIVE: This study assesses two methods used to define relatively short femur in screening for trisomy 21 and examines changes in performance of screening with gestational age. DESIGN: Retrospective analysis of data on menstrual age, femur length (FL) and biparietal diameter (BPD) in 49 trisomy 21 pregnancies and 6069 normal controls. Reference ranges were derived for BPD/FL versus menstrual age and for FL versus BPD. Two methods of defining short femur (BPD/FL and observed-to-expected FL ratio) were examined for false-positive rates and detection rates for trisomy 21 at different gestational ages. RESULTS: In the control group the BPD/FL ratio and its standard deviation decreased with menstrual age. Trisomy 21 was associated with a significantly higher BPD/FL ratio (P < 0.001) and the deviation increased significantly with menstrual age (P < 0.05). Eleven percent of 28 fetuses examined at 15-17 weeks had a BPD/FL above the 95th centile compared with 24% of 21 fetuses examined at 18-20 weeks (P = 0.40). The median observed-to-expected FL ratio in the control group was 1.0 throughout the gestational age range but the standard deviation decreased significantly with menstrual age (P < 0.01). Trisomy 21 was associated with a significantly reduced observed-to-expected FL ratio (P < 0.001) and the deviation increased significantly with menstrual age (P < 0.05). A fixed cut-off of 0.91 for observed-to-expected FL ratio provided a false-positive rate of 12% at 15-17 weeks compared with 6% at 18-20 weeks of gestation (P < 0.001) with detection rates of 29 and 38%, respectively (P = 0.73). CONCLUSION: Irrespective of the definition used to define the condition, relatively short femur is a poor marker for trisomy 21 particularly when the assessment takes place before 18 weeks of gestation.

Adult↗
PubMed2000

Fetal echogenic bowel: parameters to be considered in differential diagnosis.

OBJECTIVES: To evaluate the extent that associated findings aid in the differential diagnosis and/or prognosis of fetal echogenic bowel. METHODS: Medical history, obstetric records and outcome details were examined for 131 consecutive pregnancies with fetal hyperechogenic bowel. RESULTS: In 62 (47%) cases, there were no visible anomalies other than hyperechogenic bowel and no evidence of growth restriction. This group included four (7%) pregnancies with Down syndrome, 15 (24%) with infection or a recent episode of influenza and eight (13%) with blood staining of amniotic fluid. In the remaining 69 (53%) cases, hyperechogenic bowel was accompanied by hydrops or nuchal edema (n = 16, 12.2%), growth restriction (n = 9, 6.9%), other markers for chromosome anomalies (n = 33, 25.2%) or multiple structural anomalies (n = 11, 8.4%). In this group, the prevalence of Down syndrome was 12%, infection or influenza was reported in 14 (20%) cases and there was blood staining of amniotic fluid in seven (10%). Cystic fibrosis screening was performed in 65 (50%) pregnancies; the results were negative in all cases and clinical assessment did not indicate cystic fibrosis in any of the 91 infants who were born alive. Maternal serum screening was performed in 41 (31%) pregnancies. High alpha-fetoprotein levels were associated with multiple abnormalities or severe growth restriction. CONCLUSIONS: In many pregnancies with fetal hyperechogenic bowel, there are multiple factors that may explain these findings. Thus identification of one potential underlying cause should not preclude further testing. Once chromosome defects, cystic fibrosis, structural abnormalities, infection and growth restriction have been excluded, parents can be counseled that the prognosis is good, irrespective of the presence or absence of blood stained amniotic fluid.

Adolescent↗
PubMed1999

Peritoneal serous papillary carcinoma, a phenotypic variant of familial ovarian cancer: implications for ovarian cancer screening.

OBJECTIVE: Our purpose was to report the cancers arising during a familial ovarian cancer screening program and investigate the tumor's clonality and association with BRCA1 and BRCA2 mutations. STUDY DESIGN: Program participants with a diagnosis of ovarian cancer or peritoneal serous papillary carcinoma were identified and their demographic characteristics, ultrasonographic findings, CA 125 results, operative reports, and pathology slides reviewed. Immunohistochemical analysis of p53, bcl-2, HER-2/neu, and nm23 H1 expression was performed on tumor tissues from multiple metastatic sites, and germline BRCA1 and BRCA2 mutations were identified. RESULTS: Three stage I ovarian cancers and 7 cases of peritoneal serous papillary carcinoma were diagnosed from among 1261 program participants. Ultrasonographic abnormalities triggered surgical exploration in all 3 cases of stage I disease. Elevated levels of CA 125 were the harbinger in 2 of 7 cases of peritoneal serous papillary carcinoma, abnormal ultrasonographic findings prompted diagnosis in 2 of 7 cases, and 3 of 7 women had abdominal symptoms 5, 6, and 16 months after screening. Results of immunohistochemical studies suggested multifocal disease in 5 of 7 patients with peritoneal serous papillary carcinoma. At least 3 of the patients with peritoneal serous papillary carcinoma carry BRCA1 185delAG mutations. CONCLUSION: Multifocal peritoneal serous papillary carcinoma may be a phenotypic variant of familial ovarian cancer, and screening strategies for these women cannot rely on ultrasonography and CA 125 testing to detect early disease.

Adult↗
PubMed1999

Undiagnosed maternal phenylketonuria: the need for prenatal selective screening or case finding.

OBJECTIVES: The aims of this article are to report on a review of cases of maternal phenylketonuria in the International Maternal Phenylketonuria Collaborative Study that were initially diagnosed during or after a pregnancy, to alert health care practitioners to the possible existence of women with undiagnosed phenylketonuria whose fetuses are at risk, and to emphasize that not all adults with untreated phenylketonuria are mentally retarded. STUDY DESIGN: The study was conducted through retrospective database review. RESULTS: Of 414 women with live-born infants, 17 fulfilled our criteria. Six had phenylketonuria diagnosed after they had produced >/=1 affected offspring, 2 had phenylketonuria diagnosed as a result of transient postnatal hyperphenylalaninemia in an offspring, and 9 had phenylketonuria diagnosed by prenatal screening. Undiagnosed maternal phenylketonuria in North America and Europe is currently estimated at 1 case/100,000 births; this rate could be higher elsewhere. CONCLUSIONS: Physicians and midwives should consider a protocol of selective prenatal screening or case finding to detect undiagnosed phenylketonuria among their patients.

Adolescent↗
PubMed1999

Vaginal birth after cesarean and uterine rupture rates in California.

OBJECTIVE: To describe attempted and successful vaginal birth after cesarean (VBAC) rates and uterine rupture rates for women with and without prior cesareans, and compare delivery outcomes in hospitals with different attempted VBAC rates. METHODS: We used California hospital discharge summary data for 1995 to calculate attempted and successful VBAC rates and uterine rupture rates. We used multivariate logistic regression models to evaluate and adjust for age, ethnicity, and payment source. We report the relative risk (RR), attributable fraction, and 95% confidence intervals (CIs) for uterine rupture. RESULTS: There were 536,785 delivery discharges during 1995. The cesarean rate was 20.8%, and 12.5% of women had histories of cesareans. Of women with histories of cesareans, 61.4% attempted VBAC and 34.8% were successful. There were 392 uterine ruptures (0.07%). Women with prior cesareans were 16.98 (95% CI 13.51, 21.43) times more likely to experience uterine rupture, attributable fraction 66% (95% CI 60%, 73%). Among women with prior cesareans, those who attempted VBAC were 1.88 (95% CI 1.45, 2.44) times as likely to have uterine rupture, attributable fraction 34% (95% CI 21%, 46%). Women who delivered in hospitals with high attempted VBAC rates were less likely to have cesarean deliveries, more likely to have successful VBACs, and more likely to experience uterine ruptures. CONCLUSION: Uterine rupture occurs at a low rate in women with and without prior cesarean delivery. Risk of rupture is increased among women with prior cesarean delivery and among those who attempt VBAC.

Adult↗
PubMed1999

Cerebral MRI on fetuses submitted to repeated cocaine administration during the gestation: an ovine model.

The aim of this study was to determine the role of Magnetic Resonance Imaging (MRI) in investigating fetal cerebral lesions induced by long term exposure to cocaine during sheep pregnancy. Cerebral Magnetic Resonance Imaging was performed on two groups of fetuses at 125 days of gestation (normal gestation: 145 days). The control group consisted of eight fetuses of four pregnant ewes. The study group consisted of eight fetuses of four pregnant ewes receiving daily 140 mg/kg injection of cocaine from day 60 until delivery. The following MR sequences were applied: T1-weighted FLASH, and T2-weighted Fast-Spin-Echo. Cerebral images were evaluated semi quantitatively using the following criteria: Heterogenicity, contrast between grey and white matter, contours irregularity, hyposignal, lateral ventricle sizes. The brightness distribution and homogenicity of the images were analysed by means of edge pair distributions using a new computerized method originally designed for ultrasound images analysis developed by Ultrasight inc (USA). (1) Flash T1: Heterogenic areas and irregular contours were more frequent in cocaine exposed fetuses. The contrast between grey and white matter was more important in the cocaine group. Hyposignal was found only in the cocaine group. Enlarged lateral ventricle occurred more frequently in the cocaine group. (2) Spin echo T2: The contrast between grey and white matter was higher and the contours of the brain more irregular in the cocaine group. Heterogenicity and hyposignal were also more frequent in this group but the difference with the control group was not significant. The computerized analysis of the contrast density on the cerebral images showed that 88% of the areas exceeding the reference level concerned the cocaine group, while only 14% of the areas exceeding the reference level concerned the control group. Long term exposure to cocaine induces cerebral tissue modifications, in favor of an advanced maturation and the development of hypoxic lesions. The histology of the brains confirmed in the cocaine group, the existence of hypoxic lesions with gliosis, perivascular edema and hemorrhages, and neuronal death.

Animals↗
PubMed1999

Using the continuous quality improvement process to safely lower the cesarean section rate.

BACKGROUND: In 1994 a five-year prospective observational study (including 38,541 singleton live-born deliveries) based on maternal and neonatal hospital administrative discharge data for DRGs 370-375 was launched at Cedars Sinai Medical Center (CSMC) in Los Angeles. In 1993 a cesarean section (C-section) reduction task force was first convened and several interventions were conducted and monitored during a two-year period. In 1995 CSMC joined the Institute for Healthcare Improvement's (IHI's) national collaborative on lowering C-section rates. RESULTS: The first intervention involved physician education (grand rounds) and occurred during the preintervention baseline period. Providing physician-specific data had been implemented before participation in the IHI collaborative. Two other interventions were implemented before the collaborative versus 13 interventions after. The C-section rate decreased from 26.0% in the baseline period in 1993 to 20.5% in 1997, a 21.2% reduction. During the postintervention period, the C-section rate increased to 23.5%. There was no statistically or clinically significant increase in clavicular fractures, brachial plexus injuries, or cerebral hemorrhage in the four study years, compared to the baseline period. DISCUSSION: It is possible to safely reduce C-section delivery rates. Activities are now under way to involve additional private physician leaders in the continuous quality improvement effort. Although the small increase in the C-section rate during the postintervention period may represent statistical variation, and in itself may not be clinically significant, it supports the thesis that ongoing, continuous organizational support is required to achieve and maintain gains.

Adult↗
PubMed1998

Three-dimensional ultrasonography in obstetrics and gynecology: preliminary experience.

OBJECTIVE: Technologic advances in ultrasonographic imaging have revolutionized the management of women's health care. We recently began to evaluate the clinical applications of three-dimensional ultrasonography. STUDY DESIGN: This study prospectively evaluated 161 obstetric and gynecologic patients. Both two- and three-dimensional imaging data were acquired from real-time ultrasonography. Three orthogonal planes were displayed on a monitor and were used to create the rendered three-dimensional images. RESULTS: To date, 201 three-dimensional ultrasonographic studies have been performed, 165 transabdominally and 36 transvaginally. Transabdominally, an average of eight acquisitions per patient were obtained. Of the clinically suspected abnormalities, 29 of 32 (91%) were confirmed by three-dimensional imaging. Three of 32 (9%) improved the diagnostic capabilities or changed the diagnosis. Of the 36 transvaginal studies, an average of four acquisitions per patient were done. Thirty (83%) of these patients had suspected abnormalities and all were confirmed. CONCLUSIONS: Three-dimensional ultrasonographic imaging appears to be highly promising in the clinical setting.

Computer Systems↗
PubMed1998

The isolated choroid plexus cyst.

OBJECTIVE: To describe the karyotypes of a population of fetuses with choroid plexus cysts and compare affected fetuses with and without additional ultrasonographic findings. METHODS: The study population included all patients undergoing second-trimester ultrasound examination in a prenatal diagnostic program between January 1993 and October 1995. The records of all cases in which a choroid plexus cyst was found were reviewed, and information was abstracted regarding the fetal karyotype and the presence of other sonographic abnormalities. RESULTS: Two hundred ten cases of choroid plexus cysts were identified among 7617 patients (2.8%) who underwent second-trimester ultrasound examination. The majority of the cases (181, or 86%) involved isolated choroid plexus cysts and the remaining 29 (14%) were associated with additional ultrasonographic findings. Autosomal aneuploidy was found in one patient with an isolated choroid plexus cyst (trisomy 21) and in another with additional findings (trisomy 18); the mothers of both of these patients were at least 35 years old. For those fetuses with known outcome, the risk of aneuploidy with isolated choroid plexus cyst (one in 180) was not statistically significantly different from that associated with choroid plexus cyst accompanied by other sonographic findings (one in 26). More than 1000 fetuses with choroid plexus cysts would have to be studied to determine whether such a difference was real. CONCLUSION: Because of the rarity of aneuploidy, the reported risk for a fetus with an isolated choroid plexus cyst must be interpreted cautiously and should include the baseline risk.

Brain Diseases↗
PubMed1998

Maternal and infant complications in high and normal weight infants by method of delivery.

OBJECTIVE: To estimate the population risks of maternal and infant complications with the birth of macrosomic (at least 4000 g) compared with normal weight infants. METHODS: Term, singleton infants were identified from the state of Washington's birth event records database for 1990. Diagnosis codes from the Internal Classification of Diseases (9th revision) were used to identify delivery method and previously defined complications. We adjusted for maternal demographic and clinical factors using multivariable logistic regression to derive the risk of each maternal and infant complication. RESULTS: The incidence of macrosomia was 13% (8815 of 66,086). Vaginal birth of macrosomic infants was associated with low incidence of complications except for shoulder dystocia (11%) and postpartum hemorrhage (5%). Postpartum infection was the most common complication for women who had cesarean delivery after labor (5%), and complications for women who had cesarean without labor were rare (less than 3%). Neonatal complications were rare. Among infants with shoulder dystocia, the risks of asphyxia (adjusted relative risk [RR] 1.2, 95% confidence interval [CI] 0.6, 2.3), birth trauma (RR 0.6, 95% CI 0.2, 1.6), long-bone injury (RR 1.2, 95% CI 0.6, 2.4), seizures (RR 1.0, 95% CI 0.0, 25.0), and facial palsy (RR 2.2, 95% CI 0.2, 44.4) were not significantly different for macrosomic and normal weight infants; however, macrosomic infants had a significantly increased risk of Erb palsy (RR 3.5, 95% CI 1.8, 7.5). CONCLUSION: This population-based study showed that most macrosomic infants are delivered vaginally with low rates of maternal and neonatal complications. Macrosomic infants have higher rates of Erb palsy, but similar rates of other serious complications of shoulder dystocia when compared with normal weight infants.

Adult↗
PubMed1998

[Is ultrasound screening for ovarian cancer possible in 1998?].

Ovarian cancer is the most common cause of gynecologic cancer death, as most patients present with advanced disease, in which the prognosis is poor. Five year-survival is only 35% for all stages, while it exceeds 90% in stage I. Consequently, there has been heightened interest in the development of screening modalities that can detect ovarian cancer at an early stage to reduce the mortality of this disease. Unfortunately, transvaginal sonography and color Doppler imaging still have a high false positive rate and low specificity increasing the number of surgical procedures, even among women with a strong family history of ovarian cancer. Psychological impact and economical cost has also to be discussed when considering such programs.

Abdomen↗
PubMed1997

Effect of long-term cocaine administration to pregnant ewes on fetal hemodynamics, oxygenation, and growth.

OBJECTIVE: To assess uterine and fetal blood flows by Doppler velocimetry and fetal growth and oxygenation in pregnant ewes treated daily with cocaine and to determine whether cocaine impairs fetal cardiac and cerebral reactivity. METHODS: The study groups received 70 mg (n = 7) or 140 mg (n = 7) of cocaine and the control group (n = 7) received placebo injected intramuscularly daily on days 60-134. Hemodynamic data were measured at rest and during two acute hypoxic tests at cesarean delivery performed on day 134. RESULTS: The fetal heart rate (FHR) and umbilical and uterine resistance indices (RIs) were higher in the cocaine groups than in the control group (FHR: 187 +/- 8 and 166 +/- 8 beats per minute at 83 and 123 days, respectively, in controls and 9-11% higher in cocaine groups; umbilical RI: 0.79 +/- 0.06, 0.60 +/- 0.04, and 0.52 +/- 0.06, at 83, 105, and 123 days, respectively, in controls and 11-17% higher in the cocaine groups [P < .01]; and uterine RI: 0.40 +/- 0.05, 0.40 +/- 0.04, and 0.37 +/- 0.04, at 83, 105, and 123 days, respectively, in controls and 13-35% higher in cocaine groups [P < .05]). At delivery on day 134, the following characteristics were found to be different in the cocaine groups: fetal weight (4.03 +/- 0.2 kg in controls and 15-21% lower in the cocaine groups [P < .02]), partial pressure of oxygen (26.5 +/- 1.4 mmHg in controls and 15-16% lower in cocaine groups [P < .05]), umbilical RI (0.40 +/- 0.03 in controls and 11-17% higher in cocaine groups [P < .01]), cerebral RI (0.61 +/- 0.03 in controls and 9-15% lower in cocaine groups [P < .01]), and cerebral-umbilical ratio (1.52 +/- 0.04 in controls and 22-23% lower in cocaine groups [P < .001]). During the hypoxic tests, the cerebral RI (P < .05) and the cerebral-umbilical ratio (P < .05) decreased significantly less in the two cocaine groups. The FHR response was reduced significantly in the two cocaine groups (P < .05). CONCLUSION: Long-term exposure to cocaine induces uterine and fetal blood flow disorders, fetal growth restriction, and hypoxia. It reduces the capability of the cerebral vessels to vasodilate and the heart rate to increase during acute hypoxia.

Animals↗
PubMed1997

Placenta previa percreta with bladder involvement: new considerations and review of the literature.

Placenta previa percreta is a life-threatening condition. Antenatal diagnosis is important to establish and to optimize a plan of management. When bladder invasion occurs, other potential complications can result, including massive hemorrhage and the development of disseminated intravascular coagulation. Numerous modalities have been used successfully to treat these patients, but hysterectomy at delivery is the treatment most commonly used. A case of placenta previa percreta with suspected bladder invasion was diagnosed in a 35-year-old woman by routine office ultrasound examination at 19 weeks 6 days' gestation. She was managed conservatively until 36 weeks 3 days' gestation, at which time she underwent a modified classical Cesarean section after amniocentesis to confirm fetal lung maturity. The placenta was left in situ immediately postpartum. The patient underwent a prophylactic embolization of her hypogastric arteries and received methotrexate chemotherapy. Eight weeks later, she developed a low-grade coagulopathy and underwent a total abdominal hysterectomy. Conservative management intrapartum is thought to be appropriate, to avoid the risk of severe hemorrhage at the time of delivery. However, elective hysterectomy ought to be considered earlier (2-4 weeks postpartum) than the time suggested in the literature, to avoid the development of further complications, including coagulopathy.

Adult↗
PubMed1996

Fetal ultrasonography in maternal PKU.

Maternal phenylketonuria (PKU) is teratogenic and results in birth defects that include microcephaly, mental retardation, congenital heart disease, and intrauterine growth retardation. Treatment with a low phenylalanine diet can prevent or reduce the severity of the complications. Optimal benefit, however, requires frequent monitoring with fetal ultrasonography as a critical element. We have studied ultrasonography in 39 pregnancies enrolled in the Maternal PKU Collaborative Study and followed at our centre. First-trimester examinations in 24 pregnancies resulted in the discovery of non-viability in five. In each, this led to discontinuation of the difficult and expensive diet. Among the 33 pregnancies with second-trimester evaluation, congenital heart disease was identified in five. Two of these pregnancies were terminated. Microcephaly as determined by biparietal diameter (BPD) was identified in the second trimester in only one of nine fetuses who had microcephaly at birth. Among 20 pregnancies with third-trimester ultrasound, fetal microcephaly was identified by BPD in three of seven who had birth microcephaly. We conclude that fetal ultrasonography in maternal PKU is valuable during the first trimester in identifying non-viable pregnancies and determining gestational age and is also valuable during the second trimester in identifying congenital heart disease and perhaps other major anomalies, but not in identifying fetal microcephaly. Third-trimester ultrasound seems to be of limited usefulness.

Female↗
PubMed1995

Ovarian cancer screening. The role of ultrasound in early detection.

BACKGROUND: Because of the urgent need for effective techniques with which to detect organ-confined curable ovarian cancers, efforts have been focused on early detection. Current ovarian cancer screening trials have been hampered by deficiencies in our knowledge of the molecular and biologic events leading to ovarian tumorigenesis. The lack of early ovarian cancer symptoms and the intraperitoneal location of the ovaries contribute to the dilemma of early diagnosis. METHODS: Real-time ultrasound screening is aimed at detecting the earliest possible architectural alterations in the ovary indicative of neoplastic growth. Color Doppler imaging detects early alterations in ovarian blood flow that accompany tumorigenesis. RESULTS: To be effective, these modalities must diagnose asymptomatic curable Stage I ovarian cancers and improve ovarian disease-specific survival. Because of the relatively low prevalence of ovarian cancer in the general population, investigators have targeted women at increased risk of ovarian cancer either based on their increasing age or their family histories of cancer. Some of these studies have been underway since the late 1980s and have already demonstrated the potential usefulness and limitations of current sonographic techniques used for screening. CONCLUSIONS: Ultrasound screening for ovarian cancer has not demonstrated adequate sensitivity and specificity, thus it is not used widely outside of the clinical trial setting. Current clinical guidelines for ovarian cancer screening as well as exploratory methods for use in early ovarian cancer detection are presented.

Female↗