Composite metal substrate for thin film AlGaInP LED applications

The fabrication and feasibility assessment of n-side up, thin-epilayer, AlGaInP-based vertical light-emitting-diodes (LEDs; emitting area: 1 mm × 1 mm) with a copper-invar-copper-composite metal (CIC) substrate was obtained by wafer bonding and epilayer transferring technologies. The structure of CIC substrate is a top Cu layer of 20 μm, a middle Invar layer of 64 μm, and a bottom Cu layer of 20 μm. The invar layer consists of Fe and Ni at a ratio of 70% to 30%. The coefficient of thermal expansion for CIC is about 6.1 × 10^-6 /K, which is similar to that of the GaAs substrate (5.7 × 10^-6 /K) and AlGaInP epilayers. Due to the high thermal conductivity (160 W/m-K) of 104-μm-thick CIC, the high performances of the packaged LEDs are obtained. They present a low red shift phenomenon (from 623 to 642 nm for 100 mA to 1 A) and a high output power 212 mW at 800 mA. The CIC substrate can be extended to fabricate high-efficiency thin film LEDs with conventional vertical electrodes.

Pattern and predictors of medical care received by hepatitis B carriers during pregnancy and after delivery

OBJECTIVE

The objective of the study is to evaluate the pattern and predictors of medical care received by hepatitis B virus (HBV) carriers during pregnancy and after delivery in Hong Kong.

STUDY DESIGN

The study is a retrospective analysis.

METHODS

Pregnant HBV carriers and their infants were followed up for 9-12 months after delivery. Face-to-face interviews were conducted to investigate what medical care they received for HBV before, during and after pregnancy.

RESULTS

Data were available for 412 HBV carriers. A total of 375 (91.0%) women were known HBV carriers before pregnancy. Routine antenatal screening picked out the remaining 37 (9.0%) HBV carriers; these women were younger, more likely to be smokers and had a lower level of education (P < 0.05) than known HBV carriers. In total, 356 of 412 (86.4%) HBV carriers did not receive any medical care for HBV during pregnancy. Known HBV carrier status, history of medical check-up and the use of antiviral treatment before pregnancy were significant predictors for HBV medical care during pregnancy (P < 0.05). The results show that 217 of 412 (52.6%) HBV carriers did not receive medical care for HBV after delivery. HBV medical care before pregnancy, use of antiviral treatment before pregnancy and a higher level of education were significant predictors for postpartum HBV medical care (P < 0.05). Multivariate analysis showed that HBV medical care before pregnancy (odds ratio [OR], 7.73; 95% confidence interval [CI], 3.21-18.65; P < 0.001) and the use of antiviral treatment (OR, 5.02; 95% CI, 1.41-17.81; P = 0.013) were associated with medical care during pregnancy. Medical care before pregnancy was also associated with postpartum HBV medical care (OR, 5.05; 95% CI, 3.29-7.51; P < 0.001).

CONCLUSIONS

A significant proportion of HBV carriers did not receive HBV-related medical check-ups during and after pregnancy in Hong Kong despite the majority being aware of their carrier status. Medical care before pregnancy predicted antenatal and postpartum HBV medical care.

Identifying the genetic causes for prenatally diagnosed structural congenital anomalies (SCAs) by whole-exome sequencing (WES)

BACKGROUND

Whole-exome sequencing (WES) has become an invaluable tool for genetic diagnosis in paediatrics. However, it has not been widely adopted in the prenatal setting. This study evaluated the use of WES in prenatal genetic diagnosis in fetuses with structural congenital anomalies (SCAs) detected on prenatal ultrasound.

METHOD

Thirty-three families with fetal SCAs on prenatal ultrasonography and normal chromosomal microarray results were recruited. Genomic DNA was extracted from various fetal samples including amniotic fluid, chorionic villi, and placental tissue. Parental DNA was extracted from peripheral blood when available. We used WES to sequence the coding regions of parental-fetal trios and to identify the causal variants based on the ultrasonographic features of the fetus.

RESULTS

Pathogenic mutations were identified in three families (n = 3/33, 9.1%), including mutations in DNAH11, RAF1 and CHD7, which were associated with primary ciliary dyskinesia, Noonan syndrome, and CHARGE syndrome, respectively. In addition, variants of unknown significance (VUSs) were detected in six families (18.2%), in which genetic changes only partly explained prenatal features.

CONCLUSION

WES identified pathogenic mutations in 9.1% of fetuses with SCAs and normal chromosomal microarray results. Databases for fetal genotype-phenotype correlations and standardized guidelines for variant interpretation in prenatal diagnosis need to be established to facilitate the use of WES for routine testing in prenatal diagnosis.

Transparent Memory For Harsh Electronics

As a new class of non-volatile memory, resistive random access memory (RRAM) offers not only superior electronic characteristics, but also advanced functionalities, such as transparency and radiation hardness. However, the environmental tolerance of RRAM is material-dependent, and therefore the materials used must be chosen carefully in order to avoid instabilities and performance degradation caused by the detrimental effects arising from environmental gases and ionizing radiation. In this work, we demonstrate that AlN-based RRAM displays excellent performance and environmental stability, with no significant degradation to the resistance ratio over a 100-cycle endurance test. Moreover, transparent RRAM (TRRAM) based on AlN also performs reliably under four different harsh environmental conditions and 2 MeV proton irradiation fluences, ranging from 10¹¹ to 10¹⁵ cm^-2. These findings not only provide a guideline for TRRAM design, but also demonstrate the promising applicability of AlN TRRAM for future transparent harsh electronics.

Additional chromosomal abnormalities in core-binding factor acute myeloid leukemia

Despite sharing a similar genetic abnormality, patients with core binding factor acute myeloid leukemia (CBF-AML), which is characterized by the presence of t(8;21) or inv(16)/t(16;16), show heterogeneous survival. Other molecular or cytogenetic factors are supposed to have an impact on the prognosis. We enrolled 24 CBF-AML patients to determine the impact of cytogenetic abnormality, and c-KIT, FLT3, NPM1, and CEBPA mutations on the prognosis. Only three patients had the c-KIT mutation (3/24, 12.5%) and one had the FLT3 mutation. However, over half of the patients (14/24) harbored additional cytogenetic changes, including ten with loss of sexual chromosomes (LOS) [all in the t(8;21) group], and six had additional abnormalities (two cases had both LOS and additional abnormalities). From this small-number study, no association was found between c-KIT mutation and survival and relapse rate. However, additional chromosome abnormalities had a significant association with relapse of the disease (P = 0.027). Stem cell transplant had a trend of benefitting patients after relapse (P = 0.065). This implies that chromosome abnormalities occur in CBF-AML and might take part in the heterogeneous nature of CBF-AML.

Survey on examining prevalence of paternal anxiety and its risk factors in perinatal period in Hong Kong: a longitudinal study

BACKGROUND

There is emerging evidence of the significance of paternal mental health problems among the expectant fathers during the antenatal and postnatal period. The present study aims at determining the prevalence of paternal perinatal anxiety and identifying its risk factors among the fathers.

METHODS

A total of 622 expectant fathers were recruited in Hong Kong. The expectant fathers were assessed using standardized and validated psychological instruments on three time points including early pregnancy, late pregnancy and 6 week postnatal. Independent samples t-test, one way ANOVA, Pearson's correlation and multiple linear regression were used to examine the effect of hypothesized risk factors. Hierarchical multiple regression and mixed effect model were also conducted with potential confounding factors controlled for.

RESULTS

Results showed that a significant proportion of expectant fathers experienced anxiety during the perinatal period. Low self-esteem and poor social support were found to be risk factors of paternal anxiety across pregnancy to postnatal period. Work-family conflict could significantly predict paternal anxiety in the pregnancy period.

CONCLUSIONS

The present study points to the need for greater research and clinical attention to paternal anxiety, given that it is a highly prevalent problem and could be detrimental to their partner's well-being and children development. The present findings contributes to the theoretical understanding of the prevalence and risk factors of paternal perinatal anxiety and have implications for the design of effective identification, prevention, and interventions of these clinical problems.

Association between pregnancy-associated plasma protein-A levels in the first trimester and gestational diabetes mellitus in Chinese women

INTRODUCTION

Several studies have shown that women with pre-existing diabetes mellitus have significantly lower pregnancy-associated plasma protein-A levels than those without. This study aimed to evaluate whether first-trimester pregnancy-associated plasma protein-A multiple of median is associated with gestational diabetes mellitus in Chinese pregnant women.

METHODS

This prospectively collected case series was conducted in a regional hospital in Hong Kong. All consecutive Chinese women with a singleton pregnancy who attended the hospital for their first antenatal visit (before 14 weeks' gestation) from April to July 2014 were included. Pregnancy-associated plasma protein-A multiple of median was compared between the gestational diabetic (especially for early-onset gestational diabetes) and non-diabetic groups. The correlation between pregnancy-associated plasma protein-A level and glycosylated haemoglobin level in women with gestational diabetes was also examined.

RESULTS

Of the 520 women recruited, gestational diabetes was diagnosed in 169 (32.5%). Among them, 43 (25.4%) had an early diagnosis, and 167 (98.8%) with the disease were managed by diet alone. The gestational diabetic group did not differ significantly to the non-diabetic group in pregnancy-associated plasma protein-A (0.97 vs 0.99, P=0.40) or free β-human chorionic gonadotrophin multiple of median (1.05 vs 1.02, P=0.29). Compared with the non-gestational diabetic group, women with early diagnosis of gestational diabetes had a non-significant reduction in pregnancy-associated plasma protein-A multiple of median (median, interquartile range: 0.86, 0.57-1.23 vs 0.99, 0.67-1.44; P=0.11). Pregnancy-associated plasma protein-A and glycosylated haemoglobin levels were not correlated in women with gestational diabetes (r=0.027; P=0.74).

CONCLUSIONS

Chinese women with non-insulin-dependent gestational diabetes did not exhibit significant changes to pregnancy-associated plasma protein-A multiple of median nor a correlation between pregnancy-associated plasma protein-A with glycosylated haemoglobin levels. Pregnancy-associated plasma protein-A multiple of median was not predictive of non-insulin-dependent gestational diabetes or early onset of gestational diabetes. There was a high prevalence of gestational diabetes in the Chinese population.

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/GaAs hybrid solar cells with 13% power conversion efficiency using front- and back-surface field

Planar hybrid solar cells based on bulk GaAs wafers with a background doping density of 10(16) cm(-3) and poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (

PEDOT

PSS) demonstrated an excellent power conversion efficiency of 8.99%. The efficiency of the cell was enhanced to 9.87% with a back-surface field feature using a molecular beam epitaxially grown n-type GaAs epi-layer. The efficiency and fill factor reach 11.86% and 0.8 when an additional p + GaAs epi-layer is deposited on the surface of the solar cells, which provides a front-surface field. The interface between the high- and low-doped regions in the polymer/GaAs and GaAs formed an electric field that introduced a barrier to minority carriers flow to the substrate and effectively reduced front surface carrier recombination, thereby enhancing light-generated free carrier collection efficiency and open-circuit voltage. Compared with the device without the front- and back-surface field, the fill factor and open-circuit voltage of the hybrid solar cell were improved from 0.76 to 0.8 and from 0.68 V to 0.77V, respectively. The highest efficiency reaches a record 13% when the Zonyl fluorosurfactant-treated

PEDOT

PSS is used as a hole-transporting conducting layer for hybrid cells.

Double balloon catheter for induction of labour in Chinese women with previous caesarean section: one-year experience and literature review

OBJECTIVES

To evaluate the efficacy and safety of double balloon catheter for induction of labour in Chinese women with one previous caesarean section and unfavourable cervix at term.

DESIGN

Retrospective cohort study.

SETTING

A regional hospital in Hong Kong.

PATIENTS

Women with previous caesarean delivery requiring induction of labour at term and with an unfavourable cervix from May 2013 to April 2014.

MAJOR OUTCOME MEASURES

Primary outcome was to assess rate of successful vaginal delivery (spontaneous or instrument-assisted) using double balloon catheter. Secondary outcomes were double balloon catheter induction-to-delivery and removal-to-delivery interval; cervical score improvement; oxytocin augmentation; maternal or fetal complications during cervical ripening, intrapartum and postpartum period; and risk factors associated with unsuccessful induction.

RESULTS

All 24 Chinese women tolerated double balloon catheter well. After double balloon catheter expulsion or removal, the cervix successfully ripened in 18 (75%) cases. The improvement in Bishop score 3 (interquartile range, 2-4) was statistically significant (P<0.001). Overall, 18 (75%) cases were delivered vaginally. The median insertion-to-delivery and removal-to-delivery intervals were 19 (interquartile range, 13.4-23.0) hours and 6.9 (interquartile range, 4.1-10.8) hours, respectively. Compared with cases without, the interval to delivery was statistically significantly shorter in those with spontaneous balloon expulsion or spontaneous membrane rupture during ripening (7.8 vs 3.0 hours; P=0.025). There were no major maternal or neonatal complications. The only factor significantly associated with failed vaginal birth after caesarean was previous caesarean section for failure to progress (P<0.001).

CONCLUSIONS

This is the first study using double balloon catheter for induction of labour in Asian Chinese women with previous caesarean section. Using double balloon catheter, we achieved a vaginal birth after caesarean rate of 75% without major complications.

Fetal fibronectin test on Chinese women with symptoms of preterm labour: a pilot study

OBJECTIVE

The fetal fibronectin test is advocated to facilitate the management of women presenting with threatened preterm labour, but is underutilised in Hong Kong. This study aimed to provide experience with this test and evaluate its utility in a local setting.

DESIGN

Prospective cohort study.

SETTING

A university-affiliated hospital in Hong Kong.

PATIENTS

Women presenting with symptoms of preterm labour were recruited from 1 January 2011 to 30 June 2012.

MAIN OUTCOME MEASURES

The sensitivity, specificity, positive predictive value, and negative predictive value of the fetal fibronectin test to predict delivery within 24 hours, 48 hours, 7 days, and 14 days.

RESULTS

A total of 22 women were recruited; 12 (55%) of whom had a negative fetal fibronectin test, none of whom delivered within 7 days; six received corticosteroids and tocolysis, one of whom delivered within 14 days. The 10 remaining women had a positive fetal fibronectin test. Five of whom delivered within 7 days and two within 14 days; all of them had received corticosteroids and tocolysis. For predicting delivery within 7 days, the sensitivity and negative predictive value of the test were both 100%.

CONCLUSIONS

Our study demonstrated the high negative predictive value of the fetal fibronectin test in our local setting, which suggests that it should be utilised more readily in women presenting with threatened preterm labour.

Ultrasonographic prediction of homozygous alpha0-thalassemia using placental thickness, fetal cardiothoracic ratio and middle cerebral artery Doppler: alone or in combination?

OBJECTIVE

To compare the predictive values of three ultrasonographic parameters: placental thickness (PT), fetal cardiothoracic ratio (CTR) and middle cerebral artery peak systolic velocity (MCA-PSV), alone or in combination, in pregnancies affected by homozygous alpha(0)-thalassemia at 12-20 weeks' gestation.

METHODS

Pregnant women at risk of carrying a fetus affected by homozygous alpha(0)-thalassemia were studied from 1995 to 2006 using serial ultrasonography at 12-15 weeks, 16-20 weeks and 30 weeks' gestation. We measured CTR and PT from 1995, and MCA-PSV as well from 1997. An invasive prenatal test was offered if cardiomegaly with or without placentomegaly was detected but the MCA-PSV results were used only retrospectively for analysis.

RESULTS

Of a total of 777 at-risk fetuses studied, 138 (17.8%) were affected by homozygous alpha(0)-thalassemia. At 12-15 weeks' gestation, 598 ultrasound examinations were performed. CTR was better than both PT and MCA-PSV in the prediction of affected pregnancies. The highest sensitivity (98.3%) was achieved by the combination of CTR and/or MCA-PSV at a false-positive rate of 15.8%. At 16-20 weeks' gestation, 410 ultrasound examinations were performed, 121 of which were at the patient's first visit and 289 of which were at a follow-up visit. Both CTR and MCA-PSV predicted the affected pregnancies equally well. The sensitivity of CTR was 100.0%, but the false-positive rate was 5.2%. In contrast, the false-positive rate of MCA-PSV alone was 1.4% and that of the combination of CTR and MCA-PSV was 0%, although their sensitivities were less than 65%.

CONCLUSIONS

The data suggest that adding MCA-PSV to CTR in the prediction of homozygous alpha(0)-thalassemia can increase the sensitivity at 12-15 weeks and decrease the false-positive rate at 16-20 weeks' gestation.

A phase I study of the nitroimidazole hypoxia marker SR4554 using 19F magnetic resonance spectroscopy

Background:

SR4554 is a fluorine-containing 2-nitroimidazole, designed as a hypoxia marker detectable with ¹⁹F magnetic resonance spectroscopy (MRS). In an initial phase I study of SR4554, nausea/vomiting was found to be dose-limiting, and 1400 mg m⁻² was established as MTD. Preliminary MRS studies demonstrated some evidence of ¹⁹F retention in tumour. In this study we investigated higher doses of SR4554 and intratumoral localisation of the ¹⁹F MRS signal.

Methods:

Patients had tumours ⩾3 cm in diameter and ⩽4 cm deep. Measurements were performed using ¹H/¹⁹F surface coils and localised ¹⁹F MRS acquisition. SR4554 was administered at 1400 mg m⁻², with subsequent increase to 2600 mg m⁻² using prophylactic metoclopramide. Spectra were obtained immediately post infusion (MRS no. 1), at 16 h (MRS no. 2) and 20 h (MRS no. 3), based on the SR4554 half-life of 3.5 h determined from a previous study. ¹⁹Fluorine retention index (%) was defined as (MRS no. 2/MRS no. 1)*100.

Results:

A total of 26 patients enrolled at: 1400 (n=16), 1800 (n=1), 2200 (n=1) and 2600 mg m⁻² (n=8). SR4554 was well tolerated and toxicities were all ⩽grade 1; mean plasma elimination half-life was 3.7±0.9 h. SR4554 signal was seen on both unlocalised and localised MRS no. 1 in all patients. Localised ¹⁹F signals were detected at MRS no. 2 in 5 out of 9 patients and 4 out of 5 patients at MRS no. 3. The mean retention index in tumour was 13.6 (range 0.6–43.7) compared with 4.1 (range 0.6–7.3) for plasma samples taken at the same times (P=0.001) suggesting ¹⁹F retention in tumour and, therefore, the presence of hypoxia.

Conclusion:

We have demonstrated the feasibility of using ¹⁹F MRS with SR4554 as a potential method of detecting hypoxia. Certain patients showed evidence of ¹⁹F retention in tumour, supporting further development of this technique for detection of tumour hypoxia.

Conservative management of placenta praevia with accreta

It has been advocated that placenta accreta/percreta should be managed conservatively to avoid massive pelvic bleeding and preserve fertility. Diagnosis of this condition with high-resolution imaging investigations performed during the antenatal period facilitates discussion of management plans with other clinical disciplines (eg interventional radiologists), the patient, and her family. Three cases of placenta praevia with accreta are presented. The three cases were managed by leaving the placenta in-utero after caesarean section, using uterine arterial embolisation to control postpartum haemorrhage only when needed. In all these cases, we succeeded in conserving the uterus without major complications. With improved imaging techniques, accurate antenatal diagnosis of placenta praevia with accreta is now possible. This new approach to conservative management can be considered in order to not only conserve the uterus but also to avoid uncontrolled pelvic haemorrhaging.

Effects of alginate coated on PLGA microspheres for delivery tetracycline hydrochloride to periodontal pockets

The effects of alginate coated on tetracycline (Tc) loaded poly (D, L-lactic-co-glycolic acid) (PLGA) microspheres fabricated by double emulsion solvent evaporation technique for local delivery to periodontal pocket were investigated. Alginate coated PLGA microspheres showed smoother surface but enlarged their particle sizes compared with those of uncoated ones. In addition, alginate coated microspheres enhanced Tc encapsulation efficiency (E.E.) from 11.5 +/- 0.5% of uncoated ones to 17.9 +/- 0.5%. Moreover, all of the coated PLGA microspheres even fabricated at different conditions could prolong Tc release from 9-12 days with 50% or higher in cumulative release of Tc compared with those of uncoated ones. The swelling ratios of PLGA microspheres for alginate coated or uncoated ones, one of the possible mechanisms for enhancing Tc release for the coated ones, were measured. The results showed that 20% or higher in swelling ratio for the coated microspheres at the earlier stage of hydration (e.g. < or = 24 h) could be an important factor to result in high Tc release compared to the uncoated ones. In conclusion, alginate coated Tc loaded PLGA microspheres could enhance Tc delivery to periodontal pocket by enhancing drug encapsulated efficiency, released quantities and sustained release period compared with uncoated ones.

Application of transcervical hysterofetoscopy and cord blood collection at first trimester termination of pregnancy for fetal abnormalities

OBJECTIVE

To examine the applicability of hysterofetoscopy and cord blood collection at first trimester termination of pregnancy for fetal abnormalities.

METHODS

From 2004 to 2007, transcervical hysterofetoscopy was performed in seven patients at the same operation setting of surgical termination of pregnancy. The findings were compared with prenatal diagnosis. Feasibility of cord blood collection was also examined.

RESULTS

Out of these seven patients, six of them had prenatal ultrasound diagnosis of cystic hygroma. All of them had chromosomal abnormalities. Subcutaneous oedema was confirmed by hysterofetoscopy with good view. Another pregnancy was complicated by homozygous alpha thalassaemia and the diagnosis was confirmed by electrophoresis of fetal haemoglobin collected from umbilical cord vessel. Cord blood collection was also attempted in two other patients yielding fetal blood with minimal maternal contamination.

CONCLUSION

Transcervical hysterofetoscopy is a feasible tool in confirming external fetal structural abnormalities before surgical termination of pregnancy. It can be performed under either general anaesthesia or conscious sedation. Umbilical cord blood collection can facilitate confirmation of genetic diseases. It may also allow the potential of isolating fetal mesenchymal stem cell in first trimester.

Comparison of nuchal and detailed morphology ultrasound examinations in early pregnancy for fetal structural abnormality screening: a randomized controlled trial

OBJECTIVE

To compare the effectiveness of a nuchal scan at 10 to 14 + 6 weeks and a detailed morphology scan at 12 to 14 + 6 weeks in screening for fetal structural abnormalities.

METHODS

From March 2001 to November 2004, 8811 pregnant women were randomized into either the control group (10 to 14 + 6-week nuchal scan followed by routine 16-23-week scan) or the study group (10 to 14 + 6-week nuchal scan and 12 to 14 + 6-week detailed scan followed by routine 16-23-week scan).

RESULTS

We analyzed 7642 cases of singleton pregnancies with viable fetuses at first-trimester ultrasound examination and with known pregnancy outcome. In the control group, the detection rate of structural abnormalities in the first trimester was 32.8% (21/64; 95% CI, 21.6-45.7%) and the overall detection rate was 64.1% (41/64; 95% CI, 51.1-75.7%). In the study group, the detection rate in the first trimester was 47.6% (30/63; 95% CI, 34.9-60.6) and the overall detection rate was 66.7% (42/63; 95% CI, 53.7-78.0%). The overall detection rate in the control group did not differ significantly from that in the study group (P > 0.05).

CONCLUSIONS

When the nuchal scan is offered, a basic anatomical survey can be done in conjunction with nuchal translucency thickness measurement. A detailed ultrasound examination at this early gestational age may not be superior to the nuchal scan in screening for fetal abnormalities in the low-risk population. Though a wide range of abnormalities can be detected at 10 to 14 + 6 weeks, the routine 16-23-week scan cannot be abandoned.

Mobility asymmetry in InGaAs/InAlAs heterostructures with InAs quantum wires

Strong asymmetry of electron mobility in InGaAs/InAlAs heterostructures (lattice matched to InP) with the presence of InAs quantum wires was observed. Self-assembled InAs quantum wires, embedded in an InGaAs matrix close to the hetero-interface, has a strong effect in electron conduction in the interface channel. The low temperature mobility for electrons moving parallel to the quantum wires is much higher than that of electrons moving perpendicular to the wires. The asymmetry in mobility is attributed to the difference in scattering cross section of the quantum wires in these two directions.

Continued reduction in the incidence of birth trauma and birth asphyxia related to instrumental deliveries after the study period: Was this the Hawthorne effect?

BACKGROUND

The incidence of birth trauma and birth asphyxia related to instrumental deliveries in our obstetric unit was high (2.8%) in 1998-1999. A study was performed in 2000 to identify the risk factors. Unexpectedly, the incidence (0.6%) was reduced significantly during the study period. We attributed this phenomenon to the famous Hawthorne effect (tendency to improve performance because of awareness of being studied).

OBJECTIVES

The objectives were to study whether there is a continued reduction in the incidence of birth trauma and birth asphyxia related to instrumental deliveries in the post-study period (2001-2003) and to investigate the presence of underlying confounding factors apart from the Hawthorne effect.

METHOD

To compare the hospital obstetric statistics among the pre-study period (1998-1999), the study period (2000) and the post-study period (2001-2003), in particular the incidence of birth trauma and birth asphyxia related to instrumental deliveries, the instrumental delivery rate, the overall Caesarean section rate, the Caesarean section rate for no progress of labour, the incidence of failed instrumental delivery, the incidence of attempted instrumental delivery in the operating theatre, and incidence of direct second-stage Caesarean sections.

RESULTS

The incidence of birth trauma and birth asphyxia related to instrumental deliveries (0.6%) during the study period (2000) was significantly lower than that (2.8%) during the pre-study period (1998-1999; RR 0.27, 95% CI 0.11-0.70). This phenomenon continued into the post-study period (2001-2003) when the incidence of 1.0% was similarly lower than that in the pre-study period (RR 0.35, 95% CI 0.20-0.64). The instrumental delivery rate decreased further in the post-study period (13.5%) compared with those in the study (16.6%) and pre-study (19.5%) periods (RR 0.81, 95% CI 0.75-0.89 and RR 0.69, 95% CI 0.65-0.74, respectively). There was a marked increase in the direct second-stage Caesarean section rate in the post-study period (7.1%) compared to those in the study (0.4%) and pre-study (0.7%) periods (RR 15.9, 95% CI 5.05-49.73 and RR 9.77, 95% CI 5.28-18.08, respectively).

CONCLUSION

A change in obstetric practice was identified that may explain the continued reduction in the incidence of birth trauma and birth asphyxia related to instrumental deliveries in the post-study period.

Management and outcome of antenatally diagnosed congenital cystic adenomatoid malformation of the lung

OBJECTIVE

To review the management and outcome of babies with antenatally diagnosed congenital cystic adenomatoid malformation.

DESIGN

Retrospective cohort review.

SETTING

Tertiary neonatal care unit at Queen Mary Hospital and antenatal diagnostic centre at Tsan Yuk Hospital.

PATIENTS

Consecutive patients with antenatally suspected congenital cystic adenomatoid malformation in their concepti among antenatal patients attending Tsan Yuk Hospital from 1994 to 2002. Twenty-four of 33 cases were referred to Queen Mary Hospital for postnatal management and for whom comprehensive records were available for analysis in 23.

INTERVENTIONS

Postnatal interventions in their babies included investigational imaging for congenital cystic adenomatoid malformation and surgery.

MAIN OUTCOME MEASURES

Antenatal and postnatal outcome, as well as pathology of the excised lesions.

RESULTS

Antenatal outcome: termination of pregnancy in two cases and spontaneous abortion in one; in-utero regression was documented in nine cases and in one hydropic change was apparent. Postnatal outcome: only eight of 20 babies born alive had symptoms in neonatal period. Two developed serious infective complications in infancy, one with documented in-utero regression. Pulmonary parenchymal abnormalities were detected on computed tomography of the thorax in six of seven cases with normal or non-specific chest radiograph findings. Among nine cases with in-utero regression, congenital cystic adenomatoid malformation was confirmed by operative histology in five and abnormal computed tomography findings in three. Fifteen babies underwent surgical excision, one of whom died because of severe pre-existing pulmonary hypoplasia and nine endured minor postoperative complications. A favourable outcome was documented at a mean follow-up of 22 months (range, 2 months-7 years).

CONCLUSIONS

In-utero regression of congenital cystic adenomatoid malformation on antenatal ultrasound may not represent genuine resolution. Computed tomographic thorax should be considered in all newborns with antenatally diagnosed congenital cystic adenomatoid malformation, and if confirmed early operation before first hospital discharge is recommended.

The effects on maternal anxiety of two-dimensional versus two- plus three-/four-dimensional ultrasound in pregnancies at risk of fetal abnormalities: A randomized study

OBJECTIVE

To test the hypothesis that the use of two-dimensional (2D) ultrasonography with three-dimensional/four-dimensional (3D/4D) ultrasonography can reduce anxiety to a greater extent in women at risk of having a fetus with congenital abnormalities than the use of 2D ultrasonography alone.

METHODS

A total of 124 women attending the prenatal diagnostic clinic of a teaching hospital were randomized into the intervention group (2D ultrasonography followed by 3D/4D ultrasonography) or control group (2D ultrasonography alone). The primary outcome was maternal anxiety levels, which were assessed by the Spielberger state-trait anxiety inventory. We measured the anxiety levels in all women at the first visit, at around 18 weeks' gestation (immediately after ultrasound examinations) and at 28 weeks' gestation.

RESULTS

A short-term reduction of the state-anxiety score (by around 2 points) from the first visit to after ultrasound examinations was observed in both the intervention group and the control group. Unexpectedly, a small increase in the state-anxiety score from the first visit to 28 weeks' gestation was observed in the intervention group but not in the control group, though there was no significant difference in the changes between the two groups. Repeated measures ANOVA (analysis of variance) also showed that there was no significant interaction effect between groups and time of assessment on the state-anxiety scores (F = 1.072 and P = 0.344). About 80% of women reported a better understanding that their baby was normal after viewing 3D rather than 2D images.

CONCLUSION

This randomized study indicates that the addition of 3D/4D ultrasound does not cause a significant reduction in maternal anxiety in pregnancies at risk of fetal abnormalities compared with conventional 2D ultrasound alone.

Placental volume measured by three-dimensional ultrasound in the prediction of fetal alpha(0)-thalassemia: a preliminary report

OBJECTIVE

To evaluate the use of placental volume measured by three-dimensional (3D) ultrasound in predicting fetal homozygous alpha(0)-thalassemia (Hb-Bart's disease).

METHODS

From June 2002 to May 2004 singleton pregnancies at risk of alpha(0)-thalassemia and normal controls were studied prospectively at 9-12 weeks of gestation. Affected fetuses were suspected to have alpha(0)-thalassemia by two-dimensional (2D) ultrasound and confirmed by DNA analysis. Placental volume was measured on 3D ultrasound by a multiplanar technique. Intra- and interobserver agreement of measurements was assessed. The placental volume/crown-rump length quotient of the affected fetuses was compared with that of normal fetuses.

RESULTS

The final study group comprised 105 pregnancies; 43 were at risk of alpha(0)-thalassemia and 62 were normal controls. Eleven (10.5%) fetuses were affected by alpha(0)-thalassemia, all from the at-risk group, and the others were normal. Intra- and interobserver agreement of volume measurement by 3D ultrasound was relatively poor; this was reflected in the wide limits of agreement, which ranged from -10.82 to 40.86 mL. The mean +/- SD placental volume/crown-rump length quotient in affected pregnancies was larger than that in unaffected pregnancies (1.37 +/- 0.65 vs. 1.13 +/- 0.39), but this difference was not significant (P > 0.05).

CONCLUSIONS

Assessment of placental volume by 3D ultrasound does not seem to be superior to 2D ultrasound in the first-trimester prediction of alpha(0)-thalassemia.

A new strategy for prenatal diagnosis of homozygous alpha(0)-thalassemia

OBJECTIVES

We have shown previously that ultrasound examination performed by one experienced operator can be useful to exclude homozygous alpha(0)-thalassemia in a tertiary referral center. This study aimed to determine whether the technique was still applicable when performed by several operators and in different centers.

METHODS

At the Maternal and Neonatal Hospital of Guangzhou (MNH) and Tsan Yuk Hospital of Hong Kong (TYH), women at risk of homozygous alpha(0)-thalassemia were given the option of a non-invasive approach (using serial ultrasound examinations at 12-15, 16-20 and 25-30 weeks' gestation) to exclude an affected pregnancy. The fetal cardiothoracic ratio (CTR) was measured at each of these examinations and the placental thickness was measured at 12-15 weeks' gestation. The operators of MNH received training on the ultrasound examination techniques at TYH and the quality of the subsequent ultrasound examinations was checked regularly. The final diagnosis of homozygous alpha(0)-thalassemia was confirmed using an invasive test.

RESULTS

Of 832 at-risk pregnancies studied in the two hospitals, 168 (20.2%) were affected. The overall sensitivity and specificity of the non-invasive approach was 100% and 95.6%, respectively. At MNH, the need for an invasive test was reduced by 80.8%, and all the affected pregnancies were diagnosed before 24 weeks' gestation. The results achieved at MNH were comparable with those at TYH. The at-risk pregnancies including the affected ones presented at a more advanced gestational age at MNH. At each hospital, one affected pregnancy was missed at the 12-week scan but this was subsequently detected at the 15-18-week scan.

CONCLUSIONS

This non-invasive approach to exclude homozygous alpha(0)-thalassemia can be applicable when it is performed by several operators and in different centers.

Full karyotyping, rapid aneuploidy diagnosis or both when invasive prenatal testing is performed for diagnosis of thalassaemia?

A retrospective study was performed to compare the detection rate of chromosomal abnormalities by different approaches of full karyotyping, rapid aneuploidy diagnosis (RAD) or both when invasive prenatal testing is performed for diagnosis of thalassaemia. The karyotype results of 1120 prenatal samples obtained from thalassaemia couples from January 1985 to December 2002 in a referral centre for prenatal diagnosis were studied. The detection rate of chromosomal abnormalities by four different approaches were compared: (i) karyotyping for all samples; (ii) RAD (21,18,13,X,Y) for all samples; (iii) RAD for all samples + karyotyping for cases with ultrasound abnormalities; and (iv) RAD (21,18,13) for all + RAD (X,Y) for cases with ultrasound abnormalities consistent with Turner syndrome + karyotyping for cases with ultrasound abnormalities. Normal karyotypes were found in 1103 samples (98.5%). There were 17 cases (1.5%) of chromosomal abnormalities: four cases (0.36%) were clinically significant, eight cases (0.7%) were of borderline clinical significance and five cases (0.44%) were not confirmed by subsequent prenatal or postnatal tests. The incidences of autosomal (7/1120 = 0.63%) and sex chromosomal (5/1120 = 0.45%) abnormalities were not higher than those (0.41 and 0.22%, respectively) from newborn surveys (Hook and Hamerton, 1977) (P = 0.398 and 0.216, respectively). Approach 1 would detect all 17 chromosomal abnormalities. Approach 2 would detect three of four clinically significant chromosomal abnormalities but not detect six of eight chromosomal abnormalities of borderline clinical significance and three of five chromosomal abnormalities not confirmed by subsequent prenatal or postnatal tests. Approach 3, in addition, would be able to detect all four clinically significant chromosomal abnormalities. Approach 4 would detect all four clinically significant chromosomal abnormalities but would not detect seven of eight chromosomal abnormalities of borderline clinical significance and four of five chromosomal abnormalities not confirmed by subsequent prenatal or postnatal tests. RAD (21,18,13) for all + RAD (X,Y) for cases with ultrasound abnormalities consistent with Turner syndrome + karyotyping for cases with ultrasound abnormalities seemed to be the best approach for the detection of chromosomal abnormalities when invasive prenatal testing is performed for diagnosis of thalassaemia.

Three-dimensional extended imaging: a new display modality for three-dimensional ultrasound examination

OBJECTIVE

To describe Three-Dimensional eXtended Imaging (3DXI) as a new display modality for three-dimensional (3D) ultrasound examination of the fetus.

METHODS

The spine, palate, heart and brain were evaluated using 3D ultrasound examination at a mean gestational age of 22 weeks in 35, 31, 32 and 31 fetuses, respectively. The volume data captured were analyzed using the conventional orthogonal display mode (ODM), as well as the 3DXI, which includes the Multi-Slice View (MSV) mode and the Oblique View (OBV) mode. The MSV mode allows simultaneous display of multiple sequential parallel planes while the OBV mode allows examination of a non-standard straight or curved plane.

RESULTS

The MSV mode allowed a simultaneous display of multiple sequential parallel planes of the fetal structures, but we found some uncertainty if an isolated image in one of the multi-slice images represented the exact level of a fetal structure. The MSV mode was advantageous in one of the six cases of facial cleft by allowing the simultaneous display of bilateral clefts that were located in two different axial planes. The multi-slice images were helpful in making the diagnosis in one case of holoprosencephaly. The OBV mode allowed examination of the coronal plane across the curvature of the spine, and the 'in-plane' view of the interventricular septum in a non-gated study.

CONCLUSION

The 3DXI can display the volume data in a different manner from that which usually results from the use of more conventional ODM, and provide additional information over conventional two-dimensional sonography.

The use of fetal Doppler cerebroplacental blood flow and amniotic fluid volume measurement in the surveillance of postdated pregnancies

BACKGROUND

This prospective observational study aims at determining the distribution of fetal cerebro-placental Doppler indices and amniotic fluid volume in a homogenous group of uncomplicated postdated pregnancies at 41 weeks. The correlation with incidence of passage of thick meconium-stained liquor in labor was analyzed to decide which parameter would be useful in the surveillance of postdated pregnancies.

METHODS

The amniotic fluid volume, middle cerebral artery pulsatility index, umbilical artery pulsatility index, and cerebroplacental ratio were measured and distribution determined in 118 well-dated singleton pregnancies admitted for routine induction of labor at 41 weeks. The 10th centile and the 90th centile in each Doppler parameter and amniotic fluid volume were chosen to divide each parameter into three centile groups. The prevalence of thick meconium-stained liquor in labor in different Doppler and amniotic fluid volume centile groups was compared using Chi-square test for trend with P < 0.05 taken as statistically significant.

RESULTS

The prevalence of thick meconium-stained liquor in labor was significantly inversely correlated with the middle cerebral artery pulsatility index (P = 0.008), with significant difference across different middle cerebral artery pulsatility index centile groups (P = 0.02). There was no significant difference in the prevalence of thick meconium-stained liquor in labor or oligohydramnios across different umbilical artery pulsatility index centile groups. Neither was there significant difference in the prevalence of thick meconium-stained liquor in labor and oligohydramnios across different cerebroplacental ratio and amniotic fluid volume centile groups. Logistic regression using the 10th centile of middle cerebral artery pulsatility index confirmed that it was a significant independent predicting factor for risk of thick meconium-stained liquor in labor with adjusted odds ratio (95th CI) of 6.14 (1.6-24.1).

CONCLUSION

Middle cerebral artery pulsatility index is better than amniotic fluid volume or umbilical artery pulsatility index in predicting the risk of thick meconium-stained liquor in labor in uncomplicated postdated pregnancy at 41 weeks.

Relationship between cerebroplacental Doppler ratio and birth weight in postdates pregnancies

OBJECTIVES

To explore the relationship between cerebroplacental Doppler impedance index and birth weight in postdates pregnancies, and to evaluate the use of a combination of Doppler parameters and ultrasound biometry in the prediction of large-for-gestational age (LGA) fetuses at 41 weeks of gestation.

METHODS

The pulsatility indices of the umbilical (UA-PI) and middle cerebral (MCA-PI) arteries, the cerebroplacental pulsatility index ratio (CPR) and the estimated fetal weight (EFW) were obtained in a cohort of 181 ultrasound-dated pregnancies at 41 weeks' gestation, 2 days before induction of delivery. A regression equation was established and the correlation between umbilical artery impedance and different birth-weight centile groups was determined. A receiver-operating characteristics (ROC) curve was used to compare prediction of LGA fetuses using biometry alone with that using biometry and UA-PI.

RESULTS

UA-PI was inversely related to EFW (Spearson's correlation coefficient rho = -0.28, P < 0.001). Logistic regression showed an independent contribution of UA-PI to the birth-weight estimation (birth weight = 1356.8 - 232.0 x UA-PI + 0.65 x EFW). On ROC curve analysis, the prediction of LGA with the regression equation was comparable to that using ultrasound biometry alone.

CONCLUSION

UA-PI was inversely correlated to EFW, but the combination of ultrasound biometry and UA-PI compared with biometry alone showed similar prediction of LGA fetuses in postdates pregnancies. Further prospective trials on larger populations or groups with a higher prevalence of LGA fetuses would be needed to validate the use of the new formula.

Cost-effectiveness of prenatal screening for thalassaemia in Hong Kong

OBJECTIVES

To determine the cost effectiveness of a universal prenatal screening program for alpha- and beta-thalassaemia.

METHODS

We retrospectively reviewed our program from 1998 to 2002, and calculated the direct and indirect costs of various components.

RESULTS

18,936 women were screened at our prenatal clinic and 153 couples were subsequently referred to our Prenatal Diagnostic Centre for counselling and further investigations. In addition, there were 238 tertiary referrals and 157 self-referrals. After investigations, 84 fetuses were at risk of beta-thalassaemia major/beta-E thalassaemia, 19 of them were affected and 18 were aborted. The total expenditure on our program (HK 10.0 million dollars) would be less than the postnatal service costs (HK 40.4 million dollars) for 18beta-thalassaemia major fetuses if they were born. Of 361 women at risk of carrying a homozygous alpha0-thalassaemia fetus, 311 (86.2%) opted for the indirect approach (using serial ultrasound examinations to exclude Hb Bart's disease), and 76 (24.5%) subsequently underwent an invasive test for a definitive diagnosis. The sensitivity and false positive rate of this indirect approach was 100.0% and 2.9% respectively.

CONCLUSION

It is cost effective to run a universal prenatal screening program in an area where both beta-thalassaemia and alpha-thalassaemia are prevalent. The indirect approach can effectively avoid an invasive test in unaffected pregnancies.

Simple non-invasive prenatal detection of Hb Bart's disease by analysis of fetal erythrocytes in maternal blood

OBJECTIVE

To investigate a simple non-invasive technique for early detection of Hemoglobin (Hb) Bart's disease.

METHOD

Maternal blood smears from 8 known Hb Bart's pregnancies and 40 at-risk pregnancies were investigated. Maternal peripheral blood smears were stained with fluorescence-labeled monoclonal antibodies against alpha- and embryonic zeta-globin chains.

RESULTS

Fetal nonnucleated red blood cells, stained with anti-zeta but not with anti-alpha globin antibodies were found in 15 out of 16 affected pregnancies but were not detected in 23 out of 24 unaffected pregnancies.

CONCLUSION

Results showed that non-invasive immunofluorescence staining of maternal blood is a feasible approach for screening Hb Bart's disease before ultrasound manifestation in affected pregnancies.

Doppler study of the umbilical and fetal middle cerebral arteries in women with gestational diabetes mellitus

OBJECTIVE

To investigate the correlation between Doppler parameters in the umbilical and fetal middle cerebral arteries and pregnancy outcome in women with gestational diabetes mellitus (GDM).

METHODS

A prospective study was performed on 169 singleton GDM pregnancies in a university teaching hospital from January to December 2002. Umbilical artery (UA) pulsatility index (PI) and middle cerebral artery (MCA) PI and peak systolic velocity (Vmax) were measured every 4 weeks until delivery from the time of diagnosis of GDM. The pregnancy outcome was obtained from the hospital database. Using linear or quadratic regression, lines of best fit were drawn to compare the Doppler measurements between the two groups with normal and abnormal pregnancy outcomes.

RESULTS

One hundred and thirty-eight women with known pregnancy outcome completed the study. A total of 305 Doppler examinations were performed with one to four examinations for each woman. Thirty-eight women (27.5%) had one or more abnormal pregnancy outcomes: placental abruption, pre-eclampsia, preterm delivery, small-for-gestational age (SGA) infants, low Apgar scores, neonatal jaundice requiring treatment, sepsis, birth trauma, meconium aspiration syndrome, respiratory and neurological complications. There was extensive overlap of the UA-PI, MCA-PI and MCA-Vmax measurements between the two groups.

CONCLUSION

A Doppler study of the UA-PI, MCA-PI and MCA-Vmax was not useful in the prediction of abnormal pregnancy outcome in GDM.

Randomised trial comparing an interactive multimedia decision aid with a leaflet and a video to give information about prenatal screening for Down syndrome

OBJECTIVES

(1)To compare an interactive multimedia decision aid (IMDA) with a leaflet and a video to give information about prenatal screening for Down syndrome and (2) to determine the women's acceptance of IMDA.

METHODS

Two hundred and one women were recruited from the prenatal clinic of a university teaching hospital and randomised into the intervention group (IMDA, video, and information leaflet) or the control group (video and information leaflet).

RESULTS

There were no significant differences in the initial decision for and the final uptake of the prenatal screening test between the control and intervention groups. The proportion of women who were undecided was less than 10% in both groups. Of the women in the intervention group, 86.6% and 78.9% agreed that IMDA was user-friendly and acceptable, respectively. Significantly more women aged < 35 (88.1%) accepted IMDA than women aged > or = 35 (68.3%) (P = 0.030), but the logistic regression analysis did not confirm this finding after adjusting for other factors (computer knowledge and usage of computer).

CONCLUSION

The use of IMDA did not affect the women's overall uptake rate of the prenatal screening test for Down syndrome. More women less than 35 years accepted IMDA probably because they used computer more frequently and had more computer knowledge.

A pilot-randomized comparison of sublingual misoprostol with syntometrine on the blood loss in third stage of labor

BACKGROUND

To compare sublingual misoprostol with intravenous syntometrine use during third stage of labor by measuring the blood loss.

METHODS

Sixty women were randomized to receive either 600 micro g misoprostol sublingually or 1 ml syntometrine intravenously during the third stage of labor after spontaneous vaginal delivery. For those with risk factors of postpartum hemorrhage such as medical induction or augmentation of labor, previous third stage complications were excluded. The blood loss in labor was measured by the alkaline-hematin method, and differences in hemoglobin before and after delivery were compared.

RESULTS

There was no significant difference in the median measured blood loss between the misoprostol group and the syntometrine group (280 versus 226 ml, p = 0.45). The change in hemoglobin was comparable between the two groups. There were more women in the misoprostol group who required additional oxytocics, but the difference was not statistically significant. A major complication occurred in one patient in the misoprostol group with blood loss in excess of 1000 ml. The incidence of side effects such as shivering and pyrexia in women receiving misoprostol was significantly higher than that in the syntometrine group.

CONCLUSION

The use of sublingual misoprostol or intravenous syntometrine in spontaneous vaginal delivery resulted in a comparable amount of blood loss. Transient side effect such as fever and shivering which resolved within a day occurred more frequent to those who received sublingual misoprostol.

Increase of lipid peroxidation by cisplatin in WI38 cells but not in SV40-transformed WI38 cells

Cisplatin (CPT) is an effective anticancer drug that causes cumulative toxicity to normal tissues. It has been suggested that CPT damages normal cells by causing oxidative stress, but it is not known whether it can induce similar oxidative damage to tumor cells. In this study, by using normal human lung fibroblast (W138) cells and SV40-transformed WI38 (VA13) cells as a model, we compared the effect of CPT on cytotoxicity, apoptosis, lipid peroxidation, and mitochondrial gene expression, which could be regulated by oxidative stress, between normal and tumor cells. CPT induced greater growth inhibition and percentage of apoptotic cells in VA13 cells. However, levels of esterified F(2)-isoprostanes and 4-hydroxy-2-nonenal, two specific products of lipid peroxidation, were increased by CPT in WI38 cells, but not in VA13 cells. Furthermore, the transcript level of mitochondrial 12S rRNA was augmented by CPT in both cells, but to a higher degree in WI38 cells. The data suggest a correlation between lipid peroxidation and cytotoxicity or increased mitochondrial transcript levels in WI38 cells but not in VA13 cells. The results also indicate an altered response of oxidative damage and mitochondrial gene regulation to CPT in the transformed phenotype of WI38 cells.

Successful outcome after serial amnioreductions in triplet fetofetal transfusion syndrome

BACKGROUND

Triplet fetofetal transfusion is an extremely rare complication with high perinatal mortality. Its rarity does not allow any prospective randomized study on various interventional methods to be conducted.

CASE

We report one case of triplet fetofetal transfusion syndrome with survival of all three fetuses. Two were donor fetuses, and one was the recipient fetus. Serial amnioreductions were performed at 22, 24, and 26 weeks' gestation to relieve symptomatic polyhydramnios. Premature rupture of membranes occurred at 27 weeks and cesarean delivery was performed. All three babies were discharged home by 4 months of age, and all had normal neurological development when assessed at 6 months of age.

CONCLUSION

The option of serial amnioreduction, with the anticipation and preparation for delivery at around 28 weeks, should be seriously considered when triplet fetofetal transfusion syndrome is encountered.

Unexpected reduction in the incidence of birth trauma and birth asphyxia related to instrumental deliveries during the study period: was this the Hawthorne effect?

OBJECTIVE

The study was originally designed to identify the risk factors that could predict those difficult instrumental deliveries resulting in birth trauma and birth asphyxia.

DESIGN

A prospective study on all singleton deliveries in cephalic presentation with an attempt of instrumental delivery over a 12-month period (13 March 2000 to 12 March 2001).

SETTING

A local teaching hospital.

SAMPLE

Six hundred and seventy deliveries.

METHODS

A codesheet was designed to record the demographic data, characteristics of first and second stages of labour and neonatal outcome. In particular, the doctor had to enter the pelvic examination findings before the attempt of instrumental delivery.

MAIN OUTCOME MEASURES

Birth trauma and birth asphyxia.

RESULTS

There was a significant reduction in the incidence of birth trauma and birth asphyxia related to instrumental deliveries during the study period (0.6%) when compared with that (2.8%) in the pre-study period (1998 and 1999) (RR 0.27, 95% CI 0.11-0.70). There was more trial of instrumental deliveries in the operating theatre although this was not statistically significant (RR 1.19, 95% CI 0.88-1.60). The instrumental delivery rate decreased during the study period (RR 0.88, 95% CI 0.82-0.94). The caesarean section rate for no progress of labour, the incidence of direct second stage caesarean section and the incidence of failed instrumental delivery did not increase during the study period.

CONCLUSIONS

Apart from the merits of regular audit exercise and increasing experience of the staff, the Hawthorne effect might be the major contributing factor in the reduction of birth trauma and birth asphyxia related to instrumental deliveries during the study period.

Factors affecting outcomes of prenatally-diagnosed tumours

OBJECTIVE

The outcomes of prenatally-diagnosed tumours affect obstetrical management and parental decisions. The present study reviews the factors affecting outcomes for fetuses with prenatally-diagnosed tumours.

METHODS

Medical records of all fetuses referred to our institutions with antenatally-diagnosed tumours were reviewed for the type and location of the tumours, results of treatment and/or causes of death.

RESULTS

From January 1994 to May 2001, there were 15 fetuses with antenatally- diagnosed tumours: mesoblastic nephroma (MN) (n=2); neuroblastoma (NB) (n=2); cystic hygroma (CH) (n=3); intracranial germ cell tumour (IGCT) (n=2); sacrococcygeal teratoma (SCT) (n=3) and haemangioma (liver, n=2; limb, n=1). One mother had termination of pregnancy for her fetal SCT. Three mothers had Caesarean section for large fetal heads (CH, n=2; IGCT, n=1). Three fetuses died; two with IGCT and one with SCT, who died of heart failure. Two newborns with CH needed emergency intubation and, later, one of them had tracheostomy. One baby had cardiac failure resulting from a lower limb haemangioma and needed drug therapy. All solid tumours (MN, NB, SCT) of the live births had no recurrence after surgery with or without adjuvant chemotherapy.

CONCLUSION

Prenatally-diagnosed tumours without any other associated abnormality cause morbidity and mortality because of their location and vascularity. Solid tumours are relatively benign.

Universal antenatal human immunodeficiency virus testing in Hong Kong: consensus statement

Following the recommendations of the Advisory Council on AIDS, Hong Kong, the Hospital Authority announced plans to introduce universal antenatal screening for human immunodeficiency virus infection and hence, a consensus conference was held to discuss strategies for implementing such screening in Hong Kong. This paper reports the discussions of the consensus conference. The consensus meeting group consisted of 15 clinicians and scientists from Hong Kong, Macau, and Thailand. Seven commonly asked questions concerning mother-to-child transmission of human immunodeficiency virus were selected for discussion by the participating panellists. Information on the laboratory diagnosis of human immunodeficiency virus infection and the efficacy of preventive measures in reducing mother-to-child transmission of human immunodeficiency virus were reviewed. Data from local studies was also presented and discussed. The timing, potential problems, and cost issues involved in testing all pregnant women in Hong Kong for human immunodeficiency virus were then considered.

Appearance of shortened Bcl-2 and Bax proteins and lack of evidence for apoptosis in rat forebrain after severe experimental traumatic brain injury

To investigate whether apoptosis plays a role in traumatic brain injury (TBI), we examined the expression of Bcl-2 and Bax proteins and the release of mitochondrial cytochrome c in rat brains using Western blot analysis. Bcl-2 at the predicted 26 kDa was not detected in controls and TBI groups. However, at 1 h post-TBI, a shortened Bcl-2 protein with a molecular size of approximately 14.5 kDa was detected in the injured hemisphere (R). At 4 and 12 h post TBI, an additional bcl-2 band ( approximately 10 kDa) was detected in R. Both bands disappeared at 14 days post-injury. The predicted 21-kDa band of Bax was detected in both controls and TBI animals. In addition, two shortened Bax proteins ( approximately 18 kDa) were detected after TBI. The time course of appearance was similar to that of Bcl-2 described above. In the present study, neither cytochrome c release from mitochondria nor DNA fragmentation was detected in the forebrains of sham and TBI groups. Treatment of animals with an antioxidant N-acetylcysteine administered ip greatly diminished the levels of shortened Bcl-2 and Bax proteins. These findings suggest that the induction of shortened Bcl-2 and Bax proteins in rat brains may be associated with reactive oxygen species generated after TBI.

The effect of fetal gender on nuchal translucency at 10-14 weeks of gestation

Recent data have suggested that fetal nuchal translucency (NT) is affected by fetal gender. We investigated the size of this effect in 12 189 unselected pregnancies with known normal outcomes that had undergone NT measurements between 10 and 14 weeks of gestation. NT increased with gestation and was converted to multiples of the median (MoM) for the gestational day. The median NT MoM (95% CI) for female fetuses was 0.98 (0.97-0.99). This was significantly lower than that of the male fetuses (1.03; range 1.02-1.04) (p<0.0005; Wilcoxon rank-sum test). The gender difference was not observed at 10 weeks but was observed from 11 weeks onwards. There is no obvious explanation for the above findings.

In vivo magnetic resonance (MR) study of fatty liver: importance of intracellular ultrastructural alteration for MR tissue parameters change

Fatty liver is thought to have a shorter T1 relaxation time than normal liver tissue, due to the accumulation of triglyceride. Previous studies regarding T1 and T2 relaxation times, however, show widely different results. In order to elucidate the mechanism responsible for the changes and diversity of relaxation times in fatty liver, we created two animal models in 14 rabbits, one acute form (N = 6) and the other chronic form (N = 8). Four rabbits were taken as a control group. Tissue relaxation times and the magnetization transfer (MT) effect of the liver tissue in these two models were measured. The results were correlated with biochemical analysis of water and fat content and histological examination, including findings in light microscopy and electron microscopy. Although the fatty ratio in both forms of fatty liver was similar, their tissue relaxation rate and MT effect were significantly different. The acute form showed prolongation of both T1 and T2 relaxation times (512 +/- 51 msec vs. 710 +/- 95 msec and 39 +/- 1.8 msec vs. 48 +/- 3.7 msec, respectively) and a decrease of the MT effect (50 +/- 5.1% vs. 38 +/- 6.3%), compared to those of the control group and preinduction liver. The chronic form showed shorter T1 and T2 values (526 +/- 36 msec vs. 406 +/- 56 msec and 36 +/- 1.6 msec vs. 33 +/- 2.3 msec, respectively) and a stronger MT effect (21 +/- 0.9% vs. 26 +/- 2.3%). In acute form fatty liver, electron microscopic examination revealed dramatic subcellular changes, such as vesicular transformation, a markedly increased amount of smooth endoplasmic reticulum (SER), and disruption of the crista. These changes were not found in the chronic form fatty liver. From this study, we concluded that the ultrastructural alteration in the subcellular organelles of hepatocyte might play a crucial role for the chameleonic presentation of MR tissue parameters in fatty liver.

Azepanone-based inhibitors of human and rat cathepsin K

The synthesis, in vitro activities, and pharmacokinetics of a series of azepanone-based inhibitors of the cysteine protease cathepsin K (EC 3.4.22.38) are described. These compounds show improved configurational stability of the C-4 diastereomeric center relative to the previously published five- and six-membered ring ketone-based inhibitor series. Studies in this series have led to the identification of 20, a potent, selective inhibitor of human cathepsin K (K(i) = 0.16 nM) as well as 24, a potent inhibitor of both human (K(i) = 0.0048 nM) and rat (K(i,app) = 4.8 nM) cathepsin K. Small-molecule X-ray crystallographic analysis of 20 established the C-4 S stereochemistry as being critical for potent inhibition and that unbound 20 adopted the expected equatorial conformation for the C-4 substituent. Molecular modeling studies predicted the higher energy axial orientation at C-4 of 20 when bound within the active site of cathepsin K, a feature subsequently confirmed by X-ray crystallography. Pharmacokinetic studies in the rat show 20 to be 42% orally bioavailable. Comparison of the transport of the cyclic and acyclic analogues through CaCo-2 cells suggests that oral bioavailability of the acyclic derivatives is limited by a P-glycoprotein-mediated efflux mechanism. It is concluded that the introduction of a conformational constraint has served the dual purpose of increasing inhibitor potency by locking in a bioactive conformation as well as locking out available conformations which may serve as substrates for enzyme systems that limit oral bioavailability.

Alterations in cerebral energy metabolism induced by traumatic brain injury

Energy metabolism of the brain is unique, possessing high aerobic metabolism with no significant capacity for anaerobic glycolysis and limited tissue stores of glucose. A steady supply of oxygen and glucose is essential in order to maintain cerebral function and integrity. Extensive research in experimental and human head injury has been conducted regarding the delivery of oxygen and outcome. This research has provided evidence which indicates that in addition to the availability of oxygen and glucose, other factors, such as perturbation of mitochondrial energy transducing processes which also follow head trauma, play significant roles. In this paper, the salient findings from biochemical studies of experimental and clinical brain injury are summarized and indicate that the mitochondrial respiratory chain-linked oxidative phosphorylation and calcium transport are compromised by trauma-induced brain injury and support the idea that oxidative stress and perturbation of cellular calcium homeostasis play significant roles in traumatic brain injury.

Synthesis of a fully functionalized protected C1-C11 fragment for the synthesis of the tedanolides

[figure: see text] The use of several non-aldol aldol processes allows one to prepare a fully functionalized and completely protected C1-C11 fragment that should be useful for the total synthesis of the tedanolides.