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Biomedical subjects

Geoffrey Wong

Publications and source records attributed to Geoffrey Wong.

7 recordsLinked to original sources
PubMed2007

Obstetric complications in patients with hereditary thrombophilia identified using the LCx microparticle enzyme immunoassay: a controlled study of 5,000 patients.

Factor V Leiden (FVL) and prothrombin (PT) G20210A mutations are associated with increased risk of deep venous thrombosis, pulmonary embolism, and obstetric complications. The development of inexpensive and reliable screening methods will assist in defining subpopulations of patients at risk who should undergo testing. We used a method, developed by Abbott Laboratories (Abbott Park, IL), to study 5,000 pregnant women and evaluated the association of obstetric complications with the presence of the FVL and PT G20210A mutations. We found a statistically significant association between FVL and stillbirth. There were also trends toward an association between FVL and placental abruption and between PT G20210A and intrauterine growth retardation. In addition, an association may exist between PT G20210A and preterm delivery for white women. All other parameters studied, including miscarriage and preeclampsia, did not show a statistically significant association with FVL or PT G20210A. These results confirm the association between genetic thrombophilia and selected obstetric complications.

Boston↗
PubMed2006

Inhibition of mTOR reduces chronic pressure-overload cardiac hypertrophy and fibrosis.

BACKGROUND AND OBJECTIVE: Inhibition of established left ventricular hypertrophy (LVH) and fibrosis may bring clinical benefits by reducing cardiac morbidity and mortality. The mammalian target of rapamycin, mTOR, is known to play a critical role in determining cell and organ size. We investigated whether mTOR inhibition can inhibit the chronic pressure-overload-induced LVH and fibrosis. METHODS: Male FVB/N mice underwent transverse aortic constriction (TAC) for 5 weeks to allow for establishment of LVH, followed by treatment with the mTOR inhibitor, Rapamune (2 mg/kg per day, gavage), for 4 weeks. Echocardiography was used to monitor changes in LVH and function. Haemodynamic, morphometric, histological and molecular analyses were conducted. RESULTS: Inhibition of mTOR by Rapamune was confirmed by a suppression of activated phosphorylation of ribosomal S6 protein and eukaryotic translation initiation factor-4E due to pressure overload. Despite a comparable degree of pressure overload between the vehicle- or Rapamune-treated TAC groups, Rapamune treatment for 4 weeks attenuated TAC-induced LVH by 46%, estimated by LV weight or myocyte size, and LV fractional shortening was also preserved versus vehicle-treated control (39 +/- 1 versus 32 +/- 2%, P < 0.05). Inhibition of established LVH by Rapamune was associated with a 38% reduction in collagen content. Moreover, altered gene expression due to pressure overload was largely restored. CONCLUSION: Despite sustained pressure overload, inhibition of mTOR by a 4-week period of Rapamune treatment attenuates chronically established LVH and cardiac fibrosis with preserved contractile function.

Analysis of Variance↗
PubMed2005

Fetuses with trisomy 21 having conflicting findings on antenatal testing for fetal well-being.

OBJECTIVE: This series reports 3 cases with conflicting antenatal sonographic findings: intrauterine growth restriction, absent or reversed end-diastolic flow in umbilical artery Doppler imaging, and reassuring biophysical test results. METHODS: We conducted a retrospective review of medical records. RESULTS: Three fetuses had intrauterine growth restriction and absent or reversed end-diastolic flow in umbilical artery Doppler studies, but the biophysical test results and amniotic fluid volume assessment were normal. We found no other signs of fetal jeopardy from placental insufficiency. In these cases, trisomy 21 was established after birth by karyotyping. Ventricular septal defects and aortic regurgitation were noted in 2 of the 3 affected fetuses. CONCLUSIONS: When there is an unusual combination of antenatal sonographic findings such as presented here, fetal cardiac abnormalities and aneuploidy should be considered.

Adult↗
PubMed2003

Fast MR imaging of fetal central nervous system abnormalities.

PURPOSE: To evaluate with respect to gestational age (GA) the effect of magnetic resonance (MR) imaging on changes in diagnosis, patient counseling, and case management regarding fetuses suspected of having central nervous system (CNS) anomalies. MATERIALS AND METHODS: The authors compared images from 242 ultrasonographic (US) studies and 242 MR imaging studies of the CNS in 214 fetuses. Reference standards of postnatal physical examination, imaging, surgical, and autopsy findings were available in 171 (79.9%) fetuses. Referring physicians were surveyed on how MR imaging findings changed patient counseling or case management. Outcomes were compared with respect to GA. Statistical tests used were the Fisher exact test, Student t test, and analysis of variance. RESULTS: Confirmatory US findings were normal in 69 fetuses. MR imaging findings changed diagnosis in 46 of 145 (31.7%) fetuses with abnormal US findings. The mean GA of 72 of 145 fetuses with changes in maternal counseling (25.9 weeks) was significantly greater than that in 73 of 145 fetuses without changes in maternal counseling (22.6 weeks, P <.01). The mean GA of the 46 fetuses with changes in diagnosis (26.3 weeks) was significantly greater than that of the 99 fetuses with no major change in diagnosis (23.3 weeks, P <.01). There were 27 of 145 changes in case management, with no significant difference in mean GA of fetuses with and those without changes in case management. In fetuses with abnormal US findings, MR images were used to decide to terminate the pregnancy (n = 13; mean GA, 20.1 weeks), continue the pregnancy (n = 4; mean GA, 19.2 weeks), direct the mode and/or location of delivery (n = 5; mean GA, 30.5 weeks), and direct perinatal care (n = 5; mean GA, 30.2 weeks). CONCLUSION: When a CNS anomaly is detected or suspected at US, MR imaging may demonstrate additional findings that can alter diagnosis and case management. Changes in management are GA dependent.

Central Nervous System↗
PubMed2003

Fetal thoracic abnormalities: MR imaging.

PURPOSE: To elucidate the appearance of fetal thoracic abnormalities at prenatal magnetic resonance (MR) imaging and determine whether MR imaging yields information additional to that obtained with ultrasonography (US). MATERIALS AND METHODS: US and MR imaging data from 83 MR examinations of 74 fetuses with thoracic abnormalities and confirmatory US performed within 1 week before MR imaging were compared with respect to resulting changes in patient counseling and/or care. Lung parenchyma and lesion signal intensities and vascularity, airway, esophagus, and diaphragm appearances were reviewed retrospectively on MR images. Student t tests and analyses of variance were performed. RESULTS: MR imaging yielded information additional to that acquired with US in 28 (38%) of 74 fetuses. The additional findings were confirmed in 19 of the 28 fetuses at postnatal follow-up; no follow-up data were available for the other nine fetuses. Thoracic MR information affected care with regard to six (8%) of 74 fetuses. Mean gestational age of 15 fetuses with lung signal intensity (SI) slightly lower than that of amniotic fluid (28.4 weeks +/- 6.8 [SD]) at T2-weighted MR imaging was significantly older than that of 18 fetuses with intermediate SI (21.3 weeks +/- 4.3) (P <.05). Mean SI of 13 congenital cystic adenomatoid malformations (CCAMs) and/or sequestrations (1.74 +/- 1.05) at T2-weighted MR imaging was significantly higher than that of the normal lungs of 33 fetuses (2.63 +/-.63) (P <.001). Among nine studies in which vessels were visualized in CCAMs and/or sequestrations, six involved a normal vascular branching pattern. Portions of the esophagus were seen in 31 (36%) of 85 fetuses. Nonvisualization of a major airway was not sufficient for diagnosis of pulmonary atresia. Visualization of a portion of the esophagus did not correlate with esophageal atresia. In all except one fetus, who had anhydramnios and pulmonary hypoplasia, and the fetuses with congenital diaphragmatic hernia, at least a portion of the diaphragm was visualized at MR imaging. CONCLUSION: MR imaging yields information additional to that yielded with US in fetuses with thoracic abnormalities.

Analysis of Variance↗
PubMed2003

Placental chorangiosis associated with markedly elevated maternal chorionic gonadotropin. A case report.

BACKGROUND: Chorangiosis is a rare abnormality of placental capillary proliferation, associated with hypoxia in utero. CASE: A 23-year-old primigravida with a total human chorionic gonadotropin (hCG) level of 644,139 IU/L was referred for evaluation. Obstetric ultrasound, pelvic magnetic resonance imaging, computed tomography of the head and chest, and karyotype of the fetus were normal. Complete chorioamniotic separation occurred after amniocentesis. Placental abruption occurred at 33 weeks' gestation, and an emergency cesarean section was performed. Placental histology revealed chorangiosis. The infant was discharged on day 18 of life and did well. Postpartum the hCG level returned to 0. CONCLUSION: Elevated total serum hCG can be associated with chorangiosis. This diagnosis should be considered in cases of elevated hCG when no other anomaly is identified. Patients with elevated hCG should be monitored for placental abruption, a known consequence of chorangiosis.

Abruptio Placentae↗