First-trimester Down's syndrome screening by fetal nuchal translucency measurement in Taiwan.

BACKGROUND: Fetal nuchal translucency (NT) measurement is now widely used in many Western countries as a screening tool for Down's syndrome during the first trimester. However, at present there is no data on its use in Taiwan. The purpose of the present study was to evaluate the efficacy of NT measurement in first-trimester Down's syndrome screening in Taiwan. METHODS: We conducted a prospective study from October 1997 to May 1999. Sonographic measurement of fetal NT was performed in 1,249 fetuses at 9-14 weeks of gestation. Transabdominal ultrasound scanning was performed to obtain a sagittal section of the fetus for measuring the crown-rump length (CRL) and the maximum thickness of the subcutaneous translucency between the skin and the soft tissue overlying the cervical spine. Two different cut-off points were used for screening: a fixed cut-off point of at least 2.5 mm and a CRL-related cut-off point. In the latter method, fetuses with an NT measurement in the 95th percentile were considered at high risk for Down's syndrome. RESULTS: Three fetuses had Down's syndrome, with NT measurements of 2.1 mm, 2.7 mm, and 4.0 mm. The false positive rates for the fixed cut-off point and CRL-related cut-off point were 6.3% and 4.6%, respectively. Both methods had a sensitivity of 66.7%. However, the screening program using the CRL-related cut-off point had two advantages: a higher specificity (95.5% vs 93.8%) and a more reasonable distribution pattern for screening. CONCLUSION: This study showed that NT measurement is a potential screening tool for Down's syndrome during the first trimester in Taiwan. Using CRL-related cut-off points for screening is more reasonable than using a fixed cut-off point.

Relationship between fetal nuchal translucency and crown-rump length in an Asian population.

OBJECTIVES: To investigate the relationship between the nuchal translucency (NT) thickness and crown-rump length (CRL) in normal Asian fetuses during the first trimester. DESIGN: A prospective observational study was conducted. Ultrasound measurement of NT and CRL was offered in 879 consecutive Taiwanese fetuses between 9 weeks and 14 weeks of gestation. Regression analysis was used to analyze the relationship between the NT thickness and CRL. Fetal sex was also considered in the analysis. The distribution of multiple of median (MoM) values of the NT measurements with CRL in 10-mm intervals and the 95th centile of MoM were also calculated. RESULTS: The present study shows that NT measurements increase with increasing CRL. A fixed cut-off point through the first trimester is not appropriate. The NT thickness has no relationship with fetal sex. Expressing the NT thickness by MoM values provides a simple method for clinical practice. CONCLUSIONS: The present study offers normative data of the fetal NT thickness in an Asian population, which may improve the performance of NT measurement during the first-trimester as a screening tool for chromosomal aberrations or other congenital abnormalities in the first trimester.

Second trimester maternal serum hCG level in an Asian population: normal reference values by ultrasound dating.

OBJECTIVE: To establish normative data of maternal serum chorionic gonadotropin (hCG) during the second trimester in an Asian population. METHODS: We measured the maternal serum hCG levels in 17,955 normal singleton pregnancies between 15 and 21 weeks of gestation. The gestation age was estimated by measurement of fetal biparietal distance (BPD) in all cases. Median values of hCG at various gestational weeks were calculated and the values of hCG were converted to multiple of median (MoM). The incidences of low MoM value and high MoM value were also calculated. RESULTS: The mean and median values of hCG were 57,153 mIU/ml and 50,120 mIU/ml, respectively, at 15 weeks of gestation and then decreased to 30,898 mIU/ml and 26,226 mIU/ml, respectively, at 21 weeks. We found 8.6% and 9.4% of normal singleton pregnancies have hCG MoM values >2.0 MoM and <0.5 MoM, respectively. CONCLUSIONS: Our report provides a normal reference data of second trimester maternal hCG levels by ultrasound dating in an Asian population.

Minimal change myopathy: report of a case.

A young boy, aged 5 years 7 months, presented with generalized hypotonia and proximal muscle weakness, and had exhibited delayed motor milestones since birth, He showed talipes planovalgus, a myopathic face, nasal tone vocalization, positive Gowers' sign and decreased tendon reflexes, but there was no intellectual impairment or seizure. The serum creatine kinase level and peripheral nerve conduction velocity, as well as the electromyogram and electrocardiogram, were within normal limits. A biopsy specimen from the left biceps brachii muscle revealed minimal nonspecific changes and mild variations in fiber size with an increased number of undifferentiated type 2C fibers, but no subcellular abnormalities were found on either the histochemical or electron microscopic examinations. The patient was diagnosed as having minimal change myopathy and improved clinically in muscle strength after one year of follow-up.

Prostacyclin synthesis and deacylation of phospholipids in human endothelial cells: comparison of thrombin, histamine and ionophore A23187.

Thrombin, histamine and ionophore A23187 stimulated human endothelial cells to release arachidonic acid and synthesize prostaglandins. To compare the activation of arachidonic acid release by these three stimuli in endothelial cells, we examined the intracellular lipid metabolism by prelabeling the cells with [14C]stearic acid and [3H]arachidonic acid. Thrombin stimulated the loss of 3H and 14C label from intracellular phospholipids. At the same time [3H]arachidonic acid and prostaglandins were released into the incubation medium. Thin layer chromatography analysis indicated that prostacyclin is the major metabolite formed followed by PGF2 alpha, PGE2, HHT and PGD2. In addition, several intracellular lipid metabolites were accumulated. These include: phosphatidic acid and 1,2-diacylglycerol detected by increase of both 14C and 3H radioactivity; lysophosphatidylinositol, lysophosphatidylethanolamine, and to a smaller extent lysophosphatidylcholine and lysophosphatidylserine detected by increase of 14C radioactivity. Like thrombin, both histamine and ionophore A23187 also stimulated release of arachidonic acid and synthesis of prostaglandins. Despite the different nature of the agonists, the type and the relative amount of prostaglandins synthesized in response to histamine and A23187 were similar to that stimulated by thrombin. The relative extents of hydrolysis of phospholipids and the accumulation of phosphatidic acid, 1,2-diacylglycerol and lysophospholipids are similar to that of 3H radioactivity and prostacyclin released into the medium and follow the order: ionophore A23187 greater than thrombin greater than histamine. These results suggest that in human endothelial cells, histamine, thrombin and ionophore A23187 directly or indirectly activated both phospholipase C and phospholipase A2 and these activations most likely involve mobilization of Ca2+.