Fetal Aortic Blood Flow Velocity and Power Doppler Profiles in the First Trimester: A Comprehensive Study Using High-Definition Flow Imaging.

OBJECTIVES: This study aimed to establish reference values for fetal aortic isthmus blood flow velocity and associated indices during the first trimester, utilizing a novel ultrasonographic technique known as high-definition flow imaging (HDFI). Additionally, the correlation between Doppler profiles of aortic blood flow and key fetal parameters, including nuchal thickness (NT), crown-rump length (CRL), and fetal heartbeat (FHB), was investigated. METHODS: A total of 262 fetuses were included in the analysis between December 2022 and December 2023. Utilizing 2D power Doppler ultrasound images, aortic blood flow parameters were assessed, including aortic peak systolic velocity (PS), aortic end-diastolic velocity (ED), aortic time average maximal velocity (TAMV), and various indices such as aortic systolic velocity/diastolic velocity (S/D), aortic pulsatile index (PI), aortic resistance index (RI), aortic isthmus flow velocity index (IFI), and aortic isthmic systolic index (ISI). Concurrently, fetal FHB, NT, and CRL were evaluated during early trimester Down syndrome screening. RESULTS: Significant findings include a positive correlation between gestational age (GA) and PS (PS = 3.75 × (GA) - 15.4, r2 = 0.13, p < 0.01), ED (ED = 0.42 × (GA) - 0.61, r2 = 0.04, p < 0.01), PI (PI = 0.07 × (GA) + 1.03, r2 = 0.04, p < 0.01), and TAMV (TAMV = 1.23 × (GA) - 1.66, r2 = 0.08, p < 0.01). In contrast, aortic ISI demonstrated a significant decrease (ISI = -0.03 × (GA) + 0.57, r2 = 0.05, p < 0.05) with gestational age. No significant correlation was observed for aortic RI (p = 0.33), S/D (p = 0.39), and IFI (p = 0.29) with gestational age. Aortic PS exhibited positive correlations with NT (0.217, p = 0.001) and CRL (0.360, p = 0.000) but a negative correlation with FHB (-0.214, p = 0.001). Aortic PI demonstrated positive correlations with CRL (0.208, p = 0.001) and negative correlations with FHB (-0.176, p = 0.005). Aortic TAMV showed positive correlations with NT (0.233, p = 0.000) and CRL (0.290, p = 0.000) while exhibiting a negative correlation with FHB (-0.141, p = 0.026). Aortic ISI demonstrated negative correlations with NT (-0.128, p = 0.045) and CRL (-0.218, p = 0.001) but a positive correlation with FHB (0.163, p = 0.010). CONCLUSIONS: Power Doppler angiography with Doppler ultrasound demonstrates the ability to establish accurate reference values for fetal aortic blood flow during the first trimester of pregnancy. Notably, aortic PS, TAMV, and ISI exhibit significant correlations with NT, CRL, and FHB, with ISI appearing more relevant than IFI, PS, TAMV, and FHB. The utilization of HDFI technology proves advantageous in efficiently detecting the site of the aortic isthmus compared to traditional color Doppler mode in early second trimesters.

Retrospective analysis of stillbirth and induced termination of pregnancies: Factors affecting determination.

OBJECTIVE: The aim of this study was to identify the factors and frequencies of induced termination of pregnancies. MATERIALS AND METHODS: This is a retrospective study of 488 terminations of pregnancies (TOPs) between January 2011 and December 2021 to demonstrate the factors affecting the decision to terminate the pregnancy. All cases had been hospitalized to manage the induction of labor. Methods included serial multiple laminaria dilation of the cervix and administration of a cervical misoprostol suppository. After induction of labor, the subject may experience amniotomy, instrumental evacuation of the uterus, and even hysterotomy. Pre-procedure counseling included an agreement to share medical records (paper-based and electronic). We verified the indications for all patients seeking TOPs. All cases were performed according to known diagnostic classifications and divided into seven groups for analysis. RESULTS: The patient ages ranged from 12 to 46 years. The median maternal age was 34 years [interquartile range (IQR) 30, 37]; 52.2% had at least one prior delivery. The pre-procedure diagnosis was divided into seven groups including the following: chromosomal and genetic abnormalities (146/488, 29.9%), no intrauterine heartbeats (126/488, 25.8%), structural anomalies (84/488, 17.2%), elective termination (56/488, 11.5%), preterm premature rupture of membranes (PPROM) (42/488, 8.6%), cervical incompetence (32/488, 6.6%), and other conditions (2/488, 0.4%). After excluding elective terminations, the eleven-year rate of fetal death and stillbirth to births did not show significant changes from 2011 to 2021. CONCLUSIONS: Knowing the factors underlying the decision to induce intrauterine fetal death (IUFD) including reasons for objecting to pregnancy are important for obstetricians-they can offer better planning and medical counseling. It is important to educate all women about family planning to prevent large numbers of unwanted and unsafe pregnancy terminations.

Prenatal Diagnosis Using Chromosomal Microarray Analysis in High-Risk Pregnancies.

Background: To assess the value of chromosomal microarray analysis (CMA) during the prenatal diagnosis of high-risk pregnancies. Methods: Between January 2016 and November 2021, we included 178 chorionic villi and 859 amniocentesis samples from consecutive cases at a multiple tertiary hospital. Each of these high-risk singleton pregnancies had at least one of the following indications: (1) advanced maternal age (AMA; ≥35 years; 546, 52.7%); (2) fetal structural abnormality on ultrasound (197, 19.0%); (3) high-risk first- or second-trimester Down syndrome screen (189, 18.2%), including increased nuchal translucency (≥3.5 mm; 90, 8.7%); or (4) previous pregnancy, child, or family history (105, 10.1%) affected by chromosomal abnormality or genetic disorder. Both G-banding karyotype analysis and CMA were performed. DNA was extracted directly and examined with oligonucleotide array-based comparative genomic hybridization. Results: Aneuploidies were detected by both G-banding karyotyping and CMA in 42/1037 (4.05%) cases. Among the 979 cases with normal karyotypes, 110 (10.6%) cases had copy number variants (CNVs) in CMA, including 30 (2.9%) cases with reported pathogenic and likely pathogenic CNVs ≥ 400 kb, 37 (3.6%) with nonreported VOUS, benign, or likely benign CNVs ≥ 400 kb, and 43 (4.1%) with nonreported CNVs < 400 kb. Of the 58 (5.6%) cases with aneuploidy rearrangements, 42 (4.1%) were diagnosed by both G-banding karyotyping and CMA; four inversions, six balanced translocations, and six low mosaic rates were not detected with CMA. Conclusions: CMA is an effective first step for the prenatal diagnosis of high-risk pregnancies with fetal structural anomalies found in ultrasonography or upon positive findings.

Prenatal diagnosis of de novo int22h1/int22h2-mediated Xq28 duplication syndrome involving RAB39B following a previous ambiguous genitalia pregnancy.

OBJECTIVE: To report a prenatal diagnosis of int22h1/int22h2-mediated Xq28 duplication syndrome. CASE REPORT: Herein, we present the case of a 28-year-old female who had a previous ambiguous genitalia pregnancy without genetic abnormality that was terminated at 23+2 weeks of gestation. The fetus of the current pregnancy harbored a de novo copy number variation at the Xq recurrent region (int22h1/int22h2-flanked; including the RAB39B gene) with a 0.397 Mb microduplication. The literature suggests the clinical manifestation of int22h1/int22h2-mediated Xq28 duplication syndrome tends to show a milder clinical phenotype in females than males. Although the fetus in this case was female, taking into consideration the parents' age and culture, the family decided to terminate this pregnancy due to the genetic abnormality. CONCLUSION: Prenatally diagnosed de novo int22h-1/int22h-2-mediated Xq28 duplication syndrome exhibits variable phenotypic traits in female fetuses.

Novel prenatally diagnosed compound heterozygous PXDN variants in fetal congenital primary aphakia and blepharophimosis.

OBJECTIVE: To precision survey a fetal congenital primary aphakia molecular etiology. CASE REPORT: A case of 42 years old pregnancy woman prenatal diagnostic examination by amniocentesis conducted at 17 weeks' gestation and demonstrated a normal female karyotype. Trio studies based on chromosome microarray analysis (CMA) and Sanger's genetic analysis did not detect a pathologic variant of the FOXE3 gene. Fetal congenital primary aphakia accompanied with microphthalmia detected by sonography in the second trimester (22 weeks). MRI indicated bilateral absence of the lenses, consistent with primary congenital aphakia. Due to the poor prognosis of congenital aphakia, the parents decided to terminate the fetus and provided consent for an autopsy. Pathological analysis revealed dysplasia of the anterior segment of both eyes. However, post fetal mortem extended trio whole exon sequencing (WES) and Sanger's genetic analysis identified compound heterozygous variants in the chromosomal location 2p25.3 in the PXDN gene. CONCLUSION: Extended whole exon sequencing is an important tool to study primary congenital aphakia.

Prenatally diagnosed microdeletion in the TCOF1 gene in fetal congenital primary Treacher Collins Syndrome.

OBJECTIVE: To study prenatal diagnosis of congenital Treacher Collins syndrome, an etiology of craniofacial abnormalities. CASE REPORT: We present a case of fetal craniofacial abnormalities identified by antepartum sonography screening in the third trimester (28 weeks); features of micrognathia, hypoplastic zygomatic arches and bilateral low-set microtia were detected. Due to the unknown severity of the craniofacial abnormalities and poor prognosis, the parents decided to terminate the fetus after through counselling. A normal female karyotype was detected. The parents consented to chromosome microarray analysis (CMA), which identified a de novo mutation of the TCS1 gene locus on chromosome 5. CONCLUSION: Molecular CMA is an effective tool for prenatal diagnosis of congenital craniofacial abnormalities associated with Treacher Collins syndrome.

Novel prenatally diagnosed compound heterozygous POMT2 variants in fetal congenital primary aqueduct stenosis.

OBJECTIVE: To study the etiology of congenital hydrocephalus in genetic aqueduct stenosis. CASE REPORT: We report the case of a 31-year-old pregnant female, G2P0A1, with a history of hyperthyroidism under medical control. The patient received regular prenatal care, with no specific findings in the Level II ultrasound at 21 weeks of gestation. However, hydrocephalus was noted at GA 31 weeks. High-resolution sonography and fetal magnetic resonance imaging (MRI) reported fetal aqueduct stenosis. Maternal HSV, CMV, and toxoplasma infection were not detected. Fetal karyotype and chromosomal microarray analysis (CMA) indicated a normal. After intensive counseling, the parents decided to terminate the pregnancy due to the poor fetal prognosis. Post-mortem, a whole-exome sequencing (WES) and Sanger sequencing analysis trio study identified two compound heterozygous variants in the POMT2 gene inherited from both recessive parents. In the subsequent pregnancy, a WES survey revealed inheritance of only the maternal POMT2 gene variant; a live, healthy male baby was born. CONCLUSION: Extended WES represents a precision maternal medicine tool for novel prenatal diagnosis of congenital aqueduct stenosis.

Cervical Power Doppler Angiography with Micro Vessel Blood Flow Indices in the Auxiliary Diagnosis of Acute Cervicitis.

We have conducted cervical imaging of uterine and micro-vessel flow velocity waveforms in acute pelvic inflammatory disease (PID) by transvaginal power Doppler ultrasound (TVPDU) in order to explore the associations of sonographic parameters with simple and complex cervicitis. Thirty-eight patients with acute PID (26 with acute simple cervicitis and 12 with complex cervicitis) were enrolled for an assessment of vascular grading of cervix and micro-vessel flow velocity using TVPDU before treatment. Seven parameters, including vascular grading (VG), lowest pulsatility index (PI), resistance index (RI), peak systolic velocity (PS), end diastolic velocity (ED), time average maximum velocity (TAMV), and vascular index (VI = PS/ED), were measured and recorded. Forty-one healthy patients were assessed as the control group. Vascular grading (VG) was significantly higher in the study group than the control group (p < 0.0001). The PI, RI, and VI were significantly lower in the study group than control group (p < 0.0001). No significant associations were observed between seven sonographic parameters and acute simple or/and complex cervicitis. For acute simple cervicitis, a PI cutoff of 1.1 had a sensitivity of 85.4% and a specificity of 92.1% (area under ROC curve [AUC], 93.2%). A RI of 0.6 had a sensitivity of 85.4% and a specificity of 78.9% (AUC, 86.1%). A VI of 2.6 had a sensitivity of 85.4% and a specificity of 78.9% (AUC, 84.9%). Power Doppler angiography of micro-vessel flow velocity waveforms in the cervix could represent a practical method to assist the diagnosis of pelvic inflammatory disease presented as acute cervicitis detected on transvaginal ultrasound before medical or surgical treatment. Cervical PI may be a useful index to detect micro-vessel flow velocity waveforms in acute cervicitis and differentiate acute simple cervicitis from complex cervicitis.

The impact of prenatal screening tests on prenatal diagnosis in Taiwan from 2006 to 2019: a regional cohort study.

BACKGROUND: The purpose of this study is to evaluate the impact of prenatal screening tests on prenatal diagnosis in Taiwan's 14 years from 2006 to 2019. METHODS: The prenatal screening methods evolved from the second-trimester serum screening to combined first-trimester screening (cFTS) and then followed by the non-invasive cell-free DNA prenatal test (NIPT). The data used by the Department of Statistics, the Ministry of Health and Welfare and Department of Household Registration, Ministry of the Interior public website. RESULTS: This regional registry-based cohort retrospective study examined a total of 2,775,792 births from January 2006 to December 2019. The proportion of advanced maternal age (AMA) pregnancies increased from 11.63% in 2006 to 30.94% in 2019. Overall, invasive diagnostic testing was used in 87.22% of AMA pregnancies. The prenatal detection rate of trisomy 21 and 18 increased from 74.1% and 83.3% in 2006 to 96.9% and 98.8% in 2019, respectively. CONCLUSION: During the second-trimester and cFTS periods, the percentage of AMA pregnancies increased every year and the number of invasive procedures also accompany with increased percentage of AMA. However, during the period that NIPT were implemented, the percentage of invasive procedures decreased.

Serum procalcitonin to differentiate acute antepartum pyelonephritis from asymptomatic bacteriuria and acute cystitis during pregnancy: A multicenter prospective observational study.

OBJECTIVE: To examine whether serum procalcitonin (PCT) is useful for differentiating acute pyelonephritis (APN) from asymptomatic bacteriuria and acute cystitis during pregnancy. METHODS: A multicenter prospective observational study was conducted to compare serum white blood cell (WBC) counts, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, and PCT level among pregnant women with asymptomatic bacteriuria, acute cystitis, and APN and healthy pregnant women (controls). Utility of WBC count, ESR, CRP, and PCT biomarkers for the prediction of APN during pregnancy were measured. RESULTS: Area under the curve (AUC) values of PCT, CRP, ESR, and WBC count for predicting asymptomatic bacteriuria were 0.576, 0.628, 0.542, and 0.532, respectively; those for predicting acute cystitis were 0.766, 0.735, 0.681, and 0.597, respectively; and those for predicting acute pyelonephritis 0.859, 0.763, 0.711, and 0.732, respectively. Compared with the other inflammatory markers used to predict APN, PCT exhibited the highest AUC (0.859 [95% confidence interval (CI) 0.711-0.935]). A cutoff value of >0.25 ng/ml had a sensitivity of 87% and a specificity of 79%. CONCLUSION: Serum PCT can be a valuable addition to existing methods of differentiating asymptomatic bacteriuria, acute cystitis, and APN during pregnancy and can facilitate the early identification of APN during pregnancy.

Risk of venous thromboembolism in elderly patients with vertebral compression fracture: A population-based case-control study.

Vertebral compression fractures (VCFs) are common in elderly and are treated with immobilization. Moreover, immobilization and old age may increase venous thromboembolism (VTE) risk. However, the incidence of VCFs-related VTE is unknown in elderly. The purposes of this study were to determine the incidence of VTE among VCF patients, to explore whether percutaneous vertebroplasty (PV) intervention may reduce VTE risk in VCFs patients.We conducted a population-based case-control study by using the National Health Insurance Research Database. We identified 1407 patients aged ≥65 with VCF who received PV and 1407 VCFs patients who did not receive PV after developing a 1:1 propensity score-matched study cohort and were followed up for 5 years. Using PV intervention as the exposure factor, a cause-specific Cox's proportional hazards model was used to examine the association between PV and VTE.After propensity score matching, the mean age of the study participants was 78 years and ∼23% of the analyzed participants were men, incidence of VTE in the PV and control cohorts was 5.77 and 4.19 per 1000 person-years, respectively. Both groups were nonsignificant difference after examination with different adjustment models. Patients with VCF and a history of heart failure, coronary artery disease, receiving antihypertension medication were at a significantly increased VTE risk.Elderly patients with VCF who received PV had a neutral impact on risk of VTE. VCF patients with heart failure, coronary artery disease, and receiving antihypertension medication were prone to developing VTE should be monitored cautiously.

Detection of Atrial Fibrillation Using 1D Convolutional Neural Network.

The automatic detection of atrial fibrillation (AF) is crucial for its association with the risk of embolic stroke. Most of the existing AF detection methods usually convert 1D time-series electrocardiogram (ECG) signal into 2D spectrogram to train a complex AF detection system, which results in heavy training computation and high implementation cost. This paper proposes an AF detection method based on an end-to-end 1D convolutional neural network (CNN) architecture to raise the detection accuracy and reduce network complexity. By investigating the impact of major components of a convolutional block on detection accuracy and using grid search to obtain optimal hyperparameters of the CNN, we develop a simple, yet effective 1D CNN. Since the dataset provided by PhysioNet Challenge 2017 contains ECG recordings with different lengths, we also propose a length normalization algorithm to generate equal-length records to meet the requirement of CNN. Experimental results and analysis indicate that our method of 1D CNN achieves an average F1 score of 78.2%, which has better detection accuracy with lower network complexity, as compared with the existing deep learning-based methods.

Trisomy 21 screening based on first and second trimester in a Taiwanese population.

OBJECTIVE: This study investigates the performance of first- and second-trimester screening tests for detecting fetal trisomy 21 in a Taiwanese population. MATERIALS AND METHODS: This multicenter study 29,137 cases enrolled the chromosomal abnormality screening between 2013 and 2014 two years period from Taipei city. There were 23,990 was done the first trimester screening using a combination of fetal nuchal translucency, maternal serum ß-human chorionic gonadotropin, and pregnancy-associated plasma protein-A between 11+0 and 13+6 weeks of gestation age. Second-trimester screening was done for 5149 cases using a double test (ß-human chorionic gonadotropin and serum alpha fetoprotein) between 15 and 20 weeks of gestation. The cut-off risk for both is 1:270 or higher. RESULTS: This multicenter study 29,137 cases that completed first- and second-trimester screening, and the outcome was available in 28,726 cases. The mean maternal age of the screen-positive group was 34.6 ± 4.2 years. The first-trimester had 891 cases screening positive with a detection rate of 97.5% for fetal trisomy 21, and false positive rate of 3.5%. In the second-trimester had 334 cases screening positive, the detection rate and false positive rate were 33.3% and 6.4% for trisomy 21, respectively. CONCLUSION: The first-trimester screening had higher performance with a lower false positive rate than the second-trimester screening. First-trimester screening could reduce the rate of unnecessary invasive testing for all pregnant women.

Noninvasive prenatal diagnosis.

Prenatal examination plays an important role in present medical diagnosis. It provides information on fetal health status as well as the diagnosis of fetal treatment feasibility. The diagnosis can provide peace of mind for the perspective mother. Timely pregnancy termination diagnosis can also be determined if required. Amniocentesis and chorionic villus sampling are two widely used invasive prenatal diagnostic procedures. To obtain complete fetal genetic information and avoid endangering the fetus, noninvasive prenatal diagnosis has become the vital goal of prenatal diagnosis. However, the development of a high-efficiency separation technology is required to obtain the scarce fetal cells from maternal circulation. In recent years, the rapid development of microfluidic systems has provided an effective method for fetal cell separation. Advantages such as rapid analysis of small samples, low cost, and various designs, greatly enhance the efficiency and convenience of using microfluidic systems for cell separation. In addition, microfluidic disks can be fully automated for high throughput of rare cell selection from blood samples. Therefore, the development of microfluidic applications in noninvasive prenatal diagnosis is unlimited.

The BS/BSOB Ratio in Aneuploidy Fetuses at 11-13 Weeks Gestation.

OBJECTIVE: The posterior fossa of normal fetuses was evaluated and compared with those having chromosomal abnormalities at 11-13+6 weeks' gestation in Chinese population. METHODS: In 518 normal fetuses referred to first trimester screening, fetal brain stem (BS) and brain stem to occipital bone distance (BSOB) were measured prospectively. The BS and BSOB were also measured on stored images in fetuses with confirmed trisomy 21 (n = 38), Trisomy 18 (n = 26), Trisomy 13 (n = 8), and monosomy X (n = 8). RESULTS: The BS diameter and BSOB distance correlated linearly with fetal crown-rump length (CRL) by regression analysis. The BS to BSOB ratio was below the 5th percentile in 2 (5.26%), 11 (44%), 4 (50%) and 4 (50%) fetuses with trisomy 21, trisomy 18, trisomy 13 and monosomy X, respectively. Thus, both BS and BS/BSOB ratio were significantly lower in trisomy 18, trisomy 13 and monosomy X fetuses when compared to the reference range but not in fetuses with Trisomy 21. CONCLUSION: In ultrasound scans performed at the 11-13(+6) gestation weeks, fetuses with trisomy 18, 13, and monosomy X had lower BS/BSOB ratios. But trisomy 21 fetuses did not show significant differences in posterior fossa compared to the normal population.

Extended first-trimester screening using multiple sonographic markers and maternal serum biochemistry: a five-year prospective study.

OBJECTIVE: To examine the performance of first-trimester screening test combining several fetal sonographic and maternal biochemical markers for major aneuploidy in a Chinese population. METHODS: This was a prospective study performed over 5 years between January 2005 and December 2010 in Taiwan, with 20,586 cases that had a combination of a variety of sonographic markers and maternal serological ß-human chorionic gonadotropin and pregnancy-associated plasma protein-A levels assessed at first trimester screening between 11(+0) and 13(+6) weeks of gestation. The risk of aneuploidy was calculated using algorithm software developed by Fetal Medicine Foundation, London. Fetal karyotyping was performed when the prenatal screening showed a risk of 1/300 or higher. All cases were followed for fetal outcome. RESULTS: The study population was divided into four groups according to the screening strategy performed. The combination of maternal serological biochemistry and nuchal translucency measurement had a 66.7% detection rate of trisomy 21. Addition of nasal bone status increased the detection rate of trisomy 21 to 88.2%. Inclusion of tricuspid regurgitation flow showed an 87.5% detection rate of trisomy 21. Further inclusion of ductus venosus flow increased the detection rate of trisomy 21 to 100%. Incorporating more markers greatly increased the detection rate and decreased the false-positive rate (FPR). CONCLUSION: Extension of first-trimester screening to include more sonographic markers greatly increased the sensitivity and decreased FPR for detection of chromosomal abnormalities. Such screening strategy is effective in clinical practice for the Chinese ethnic population.

Noninvasive prenatal testing for whole fetal chromosomal aneuploidies: a multicenter prospective cohort trial in Taiwan.

OBJECTIVE: To evaluate the performance of noninvasive prenatal testing for all fetal chromosomal aneuploidies in an extremely high-risk group undergoing first trimester combined Down syndrome screening. METHOD: A multicenter cohort prospective study in Taiwan was performed between June and December 2012. Maternal plasma was collected and shotgun massive parallel sequencing was performed on each fetal chromosome. 201 Taiwanese pregnant women at >12 weeks' gestation from 11 medical centers were enrolled in this trial. The extremely high-risk group was defined as a Down syndrome risk cutoff >1:30 or nuchal translucency >3.0 mm (n = 100), while the low-risk group was defined as a Down syndrome cutoff <1:1,500 (n = 101). Amniocentesis confirmation was performed and birth outcome was also recorded. RESULTS: There were 11 cases of trisomy 21, 8 cases of trisomy 18, 3 cases of trisomy 13, 1 case of trisomy 16, 3 cases of 45,X, and 1 case of 47,XYY detected prenatally in 100 extremely high-risk gravidas [n = 27/100 (27%)]. The overall autosomal or sex chromosome aneuploidy detection rate was 96% (27/28) because of an insufficient amount maternal plasma for one fetus with Turner syndrome. In the low-risk group, no chromosomal abnormalities were detected (specificity = 100%). There were no false-positive cases in this study. CONCLUSIONS: This first trial in Taiwan shows that noninvasive prenatal testing for whole chromosome aneuploidies can be efficiently applied in extremely high- and low-risk populations.

The fetal frontomaxillary facial angle in normal and trisomy 21 ultrasounds at 11-13(+6) weeks of gestation: findings among the ethnic Chinese compared with Caucasian.

OBJECTIVE: The aim of this research was to compare the fetal frontomaxillary facial (FMF) angle between normal and trisomy 21 fetuses at 11(+0) -13(+6) weeks gestation in a Chinese population. METHODS: A prospective observational study was performed that included 640 euploid and 45 trisomy 21 singleton pregnancies undergoing first trimester ultrasound screening between 11 and 13(+6) weeks of gestation. The FMF angle was measured in the midsagittal plane using the standard technique. RESULTS: The fetal mean FMF angle decreased with the increasing crown-rump length (CRL) from 88.6°at a CRL of 45 mm to 78.5° at a CRL of 84 mm (FMF angle = 100.212 - 0.258 × CRL, R(2) = 0.222, p < 0.001). The overall mean FMF angle in the euploid population was 82.9° ± 4.1° and in trisomy 21 cases, 92.3° ± 5.2°. CONCLUSIONS: Fetal FMF angle is affected by gestational age in a Chinese population, although it remains a significant predictor of fetal trisomy 21.

Structural basis for the inhibition of 1,3-1,4-ß-D-glucanase by noncompetitive calcium ion and competitive Tris inhibitors.

In this paper, we determine the mutant W203F structure of TFsß-glucanase, which contains aromatic residue Trp203 at the active site of the enzyme. Residue Trp203 is stacked with the glucose product of cellotriose. Further analysis reveals that two extra calcium ions and a Tris molecule bind to the mutant structure. A Tris molecule, bound to the catalytic residues of Glu56 and Glu60, was found at the position normally taken by substrate binding at the -1 subsite. In addition, a second Ca(2+) ion was found near the residues Phe152 and Glu154 on the protein's surface, and a third one near the active site residue Asp202. Kinetic experiments reveal that both Tris and imidazole are competitive inhibitors, while calcium is a noncompetitive inhibitor for TFsß-glucanase. The two types of enzymatic inhibition are first-time descriptions for the glycosyl hydrolase family 16.