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Terence T Lao

Publications and source records attributed to Terence T Lao.

At least 19 recordsLinked to original sources
PubMed2006

Efficacy of different vasodilators on human umbilical arterial smooth muscle under normal and reduced oxygen conditions.

The ability of the smooth muscle of the human umbilical artery to relax may vary under physiological and pathological conditions. We investigated the responsiveness of that preparation to relaxation, as well as the influence of reduced oxygen condition on these responses. Rings of human umbilical arteries from full-term Caesarian deliveries were suspended in modified Krebs-Henseleit solutions bubbled with a gas mixture of 95% O2:5% CO2 (normal oxygen condition) or 2.5% O2:8% CO2 balanced with N2 (reduced oxygen condition). These rings were contracted with potassium chloride, serotonin or the thromboxane A2 mimetic U46619, before being exposed to either the nitrovasodilator sodium nitroprusside, the potassium channel opener levcromakalim or the calcium channel antagonist amlodipine. While sodium nitroprusside elicited relaxation in this blood vessel, the maximal relaxation to the nitric oxide donor was significantly smaller than that induced by levcromakalim and amlodipine. The nature of the constrictor agent used, or changes of oxygen conditions did not significantly affect the relaxation profile of this human blood vessel. These data suggest that the smooth muscle of the human umbilical artery may be less responsive to vasodilators that act via the nitric oxide pathway. Moreover, vascular responses of umbilical arterial smooth muscle to relaxing agents do not alter under hypoxic or different vasoconstricting conditions.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2006

Fetal haematocrit is a determinant of placental size in term pregnancies.

Placental size may be influenced by maternal factors, placental function as well as the fetal condition. So far, no studies have examined how the fetal oxygen-carrying capacity or haemoglobin/haematocrit levels would affect placental growth in normal human pregnancies. The aim of this study was to investigate the relationships between placental size and fetal arterial cord blood haemoglobin and haematocrit levels at the time of caesarean delivery. Umbilical arterial cord blood was taken for arterial haemoglobin and haematocrit levels immediately after delivery. The relative placental size (defined by the ratio of placental weight to fetal weight) was inversely correlated with both arterial haemoglobin (r = -0.455, p = 0.001) and haematocrit levels (r = -0.425, p = 0.003) in women who had undergone elective caesarean sections. No significant correlation was found between the relative placental size with other maternal and fetal factors.

Adult↗
PubMed2005

Thyroid disorders in pregnancy.

PURPOSE OF REVIEW: There is now increasing understanding of the association between not only overt, but also subclinical, thyroid disorders and dysfunction with adverse reproductive outcome. In particular, hypothyroidism and thyroid autoimmunity disorders have been shown to have both short- and long-term consequences on mother and child. An updated review is merited to revise many of the traditional views on thyroid disorders in pregnancy. RECENT FINDINGS: Thyroid disorders constitute the commonest group of pre-gestational endocrine disorders found in pregnant women. In mothers taking antithyroid medications, breastfeeding is considered safe. The relatively high prevalence of hypothyroidism, especially subclinical hypothyroidism, the significance of screening and treatment, and the roles of iodine insufficiency and thyroid antibodies on the outcome of pregnancy and long-term neurological development of the offspring have been documented. In hypothyroid women, the dose of thyroxine replacement often needs to be adjusted from as early as the first trimester to maintain an adequate circulating thyroxine concentration. SUMMARY: Apart from overt hyperthyroidism and hypothyroidism diagnosed before and during pregnancy, biochemical abnormalities or evidence of thyroid autoimmunity in clinically euthyroid women can affect both obstetric outcome and long-term neurological development of the offspring. Screening for thyroid function and autoimmunity, and timely and appropriate treatment, will improve pregnancy outcome. The thyroid function of infants born to mothers with thyroid disorders should also be assessed as serial monitoring and treatment may be necessary.

Female↗
PubMed2005

Relationship between caloric intake and pregnancy outcome in diet-treated gestational diabetes mellitus.

A prospective observational study was performed to examine the relationship between estimated caloric intake with maternal blood glucose profile and infant outcome in a group of Chinese women with gestational diabetes mellitus (GDM) treated by diet alone. Following the diagnosis of GDM according to the World Health Organization (WHO) criteria, and using a 75 g oral glucose tolerance test (OGTT), 62 non-obese Chinese women who had completed a 5-day dietary survey were recruited into the study. They were categorized by their mean caloric intake over 5 days into tertiles for comparison of gestational weight gain, glycemic control and pregnancy outcome. Subjects in the highest tertile had a mean intake close to the prescribed intake. No differences were seen in maternal characteristics, gestational weight gain, OGTT, other postprandial glucose concentrations, or infant outcome among the tertiles. Our findings indicated that as long as the caloric intake did not exceed that prescribed, the infant outcome remained satisfactory.

Adult↗
PubMed2004

Neonatal hyperthyrotropinemia in gestational diabetes mellitus and perinatal complications.

The aim of this study is to explore the relationship between high cord blood thyroid-stimulating hormone (TSH) level and in-utero stress to the fetus in gestational diabetes mellitus (GDM). Cord blood TSH results were analyzed in 1,578 euthyroid infants from singleton pregnancies with GDM: 103 with elevated TSH (>16 mIU/l) and 1,475 with normal TSH. Maternal characteristics, pregnancy outcome and perinatal complications were compared between the two groups. Multiple logistic regression was used to study the association between high cord blood TSH level and various perinatal complications which reflect in-utero stress in GDM after adjusting for the confounding effects of parity, instrumental delivery, cesarean section and baby gender. High cord blood TSH level was found to be associated with the 1-min Apgar score <7 (OR 3.31, 95% CI 1.78-6.16), birth trauma (OR 3.44, 95% CI 1.11-10.69), neonatal jaundice requiring treatment (OR 2.08, 95% CI 1.30-3.32), neonatal sepsis (OR 2.34, 95% CI 1.24-4.42), respiratory complications (OR 3.45, 95% CI 1.37-8.70), neurological complications (OR 8.01, 95% CI 1.91-33.60) and overall perinatal morbidity (OR 2.41, 95% CI 1.58-3.67). Cord blood TSH level seems to be a better and independent indicator of the in-utero stress to the fetus in GDM when compared to the commonly used sugar profile result and HbA1c level.

Adult↗
PubMed2004

Rapid aneuploidy screening (FISH or QF-PCR): the changing scene in prenatal diagnosis?

The accuracy of new molecular diagnostics, fluoresence in situ hybridization or quantitative fluorescence-PCR (collectively known as rapid aneuploidy screening), in prenatal diagnosis has already been demonstrated in a number of large studies. The challenge now is how to apply them clinically in the most cost-effective manner. It is now time to appraise whether rapid aneuploidy screening can replace traditional karyotyping when amniocenteses are performed for increased risk of Down's syndrome by maternal serum screening or advanced maternal age in the absence of ultrasound abnormality. The ten most recent studies from the literature within this research theme are reviewed and the pros and cons of this new approach in prenatal diagnosis are discussed, including the suggestion of future studies.

Amniocentesis↗
PubMed2004

Impact of iron deficiency anemia on prevalence of gestational diabetes mellitus.

OBJECTIVE: Increased Hb and ferritin have been associated with gestational diabetes mellitus (GDM). This study was performed to determine whether the prevalence of GDM is influenced by iron deficiency anemia. RESEARCH DESIGN AND METHODS: In a retrospective case-control study, 242 women with iron deficiency anemia (Hb<10 g/dl with features of iron deficiency) were compared with 484 nonanemic women matched for year of birth, who were delivered within the same 24-month period in our hospital, with respect to maternal demographics, infant outcome, and the prevalence of GDM diagnosed according to the World Health Organization criteria. RESULTS: There was no difference in the prepregnancy weight or BMI, but the anemic group had more multiparas and significantly lower gestational weight and BMI increments and prevalence of GDM (odds ratio [OR] 0.52, 95% CI 0.27-0.97), which was inversely correlated (P=0.045) with the duration of anemia. To determine the independent effect of anemia on GDM, multiple logistic regression analysis was performed adjusting for the effects of multiparity and BMI, and anemia was confirmed to be significantly associated with decreased prevalence of GDM (adjusted OR 0.46, 95% CI 0.23-0.90). CONCLUSIONS: The prevalence of GDM is reduced in iron deficiency anemia, which probably served as a surrogate for other factors such as nutritional inadequacy and reduced gestational weight gain. Further studies on the relationship between nutritional improvement and the increasing prevalence of GDM in the developing world are warranted.

Adult↗
PubMed2004

Maternal serum level of placental growth factor in diabetic pregnancies.

OBJECTIVE: To determine if maternal serum placental growth factor (PlGF) concentration at 11-14 weeks in pregnancies complicated by diabetes, including those with preexisting diabetes and those that developed gestational diabetes subsequently, differed from that in normal, uncomplicated pregnancies. STUDY DESIGN: PlGF concentration was measured in stored maternal serum samples obtained at 11-14 weeks of gestation from 82 women with diabetic pregnancies, including 32 with preexisting diabetes and 50 with gestational diabetes, and 400 normal controls. Gestational diabetes mellitus was diagnosed with the 75-g oral glucose tolerance test and by applying World Health Organization criteria. RESULTS: When expressed as the multiple of the median and adjusted for gestation, the log transformed values of PlGF were significantly higher (P < .05) in the diabetic group (mean multiple of the median, [MoM] 1.14; SD 0.11) as compared to the controls (mean MoM, 1.00; SD, 0.11). On further comparison between the diabetic groups with the controls, significant differences were found in the groups with gestational diabetes (mean MoM, 1.15; SD, 0.12) and non-insulin dependent diabetes (mean MoM, 1.16; SD, 0.09) but not in those complicated by insulin-dependent diabetes (mean MoM, 1.09; SD, 0.10). CONCLUSION: These findings suggest that in the first trimester of pregnancy the level of maternal PIGF was already significantly increased not only in pregnancies complicated by noninsulin dependent diabetes but also in those with gestational diabetes. The implications of these findings remain to be explored.

Adult↗
PubMed2003

Rapid recurrence of endometrioma after transvaginal ultrasound-guided aspiration.

OBJECTIVE: Ultrasound-guided aspiration is a less invasive management option for recurrent endometrioma. We postulated that the endometriotic tissue in the epithelial lining of endometrioma had undergone pressure atrophy after a period of observation, and resolution of the endometrioma can be achieved by aspiration of its content. STUDY DESIGN: A prospective study was carried out in which patients with recurrent endometrioma that remain stationary in size for a period of at least 6 months were included. Ultrasound-guided aspiration of endometrioma was performed transvaginally under conscious sedation. Ultrasound scan examination was performed at 1, 3, 6, and 12 months after aspiration to detect recurrence. RESULTS: Eight endometriomas were aspirated in six patients. The mean diameter and volume of endometrioma at aspiration were 31.0 mm (range, 18.0-46.3 mm) and 21.9 ml (range, 3.16-52.0 ml), respectively. There were no major complications. Cytological examination revealed hemosiderin-laden macrophages; neither malignant cells nor endometrial cells were detected in all cases. Six ovarian cysts recurred in five women (83.3%), all recurrence were detected within 3 months after aspiration. CONCLUSION: We concluded that although transvaginal ultrasound-guided aspiration is a safe procedure, but the recurrence rate after aspiration is unacceptably high, and hence cannot be recommended as a treatment option for recurrent endometrioma.

Endometriosis↗
PubMed2003

Can amnio-polymerase chain reaction alone replace conventional cytogenetic study for women with positive biochemical screening for fetal Down syndrome?

To determine whether amnio-polymerase chain reaction (amnio-PCR) can replace conventional cytogenetic study for confirming the karyotype of fetuses in women with positive biochemical screening for fetal Down syndrome. To check the accuracy of this technique in our laboratory, we first compared the amnio-PCR results with those of conventional cytogenetic study in 235 patients referred from June 1999 to December 2001 for prenatal diagnosis in a referral center in Hong Kong. We then reviewed the results of 1526 amniotic fluid cultures performed for positive fetal Down syndrome screening between January 1997 and December 2001 and classified them as detectable or not detectable by amnio-PCR, using the assumption that we had replaced conventional cytogenetic study with amnio-PCR. The 235 amnio-PCR results were all informative, without a false-positive or false-negative result. Of the 1526 cases with positive fetal Down syndrome screening and no ultrasound abnormalities, only two cases of sex chromosome abnormalities and two cases of marker chromosomes would have been missed if conventional cytogenetic study had been replaced by amnio-PCR.Amnio-PCR can be an alternative to conventional cytogenetic study for women with positive biochemical screening for fetal Down syndrome and no demonstrable fetal structural abnormality.

Adult↗
PubMed2003

First-trimester blood pressure and gestational diabetes in high-risk Chinese women.

OBJECTIVE: Gestational diabetes mellitus (GDM) is associated with increased incidence of hypertensive disorders of pregnancy, which is attributed to maternal insulin resistance and hyperinsulinemia. A retrospective case-control study was performed to examine the relationship between first-trimester blood pressure (BP) and the subsequent development of GDM in high-risk Chinese women. METHODS: The systolic and diastolic BP readings at the 9th-12th week of gestation were compared between 67 women with GDM and 64 high-risk controls matched for age (+/- 1 year), height (+/- 1 cm), and booking weight (+/- 1 kg), all with singleton pregnancies and delivered within 1 year. The entire cohort was further categorized into systolic and diastolic BP quartile groups based on reference values established in 215 consecutive pregnant women, and the incidence of GDM was correlated with the quartile ranking. RESULTS: The GDM group had significantly higher systolic BP (114.0 +/- 12.9 mmHg versus 108.0 +/- 10.6 mmHg, P =.004) at the 9th-12th week. There was a positive and significant correlation between the incidence of GDM and systolic BP, but not diastolic BP, quartiles, and systolic BP above the median value (109 mmHg) was associated with increased incidence of GDM. Regression analysis with adjustment for the effects of age over 35 years and weight greater than 75 kg confirmed that systolic BP above median was a significant risk factor for GDM (OR 4.20, 95% CI 1.97, 8.94). CONCLUSION: The correlation between first-trimester systolic BP quartiles and incidence of GDM could be a feature of insulin resistance and hyperinsulinemia before the development of GDM in high-risk Chinese women.

Adult↗
PubMed2003

5-hydroxytryptamine and thromboxane A2 as physiologic mediators of human umbilical artery closure.

OBJECTIVE: This study investigated the response of the human umbilical artery to various agonists in order to determine which agents might be involved in umbilical cord closure. METHODS: Umbilical artery rings from 22 cesarean deliveries were suspended in tissue baths containing Krebs-Henseleit solution under low and normal oxygen conditions. Samples were challenged with 5-hydroxytryptamine, acetylcholine, angiotensin II, bradykinin, endothelin-1, histamine, norepinephrine, phenylephrine, and U46619 (a thromboxane A(2) mimetic). RESULTS: Only 5-hydroxytryptamine, bradykinin, endothelin-1, histamine, and U46619 produced appreciable maximal contractions. Furthermore, although the contractile force generated by these agonists was diminished in normal oxygen conditions, this reduction affected responses to 5-hydroxytryptamine and U46619 least. CONCLUSION: 5-Hydroxytryptamine and U46619 demonstrated the characteristics most likely to be associated with closure of the umbilical artery, ie, they elicited strong, sustained contractions at physiologic concentrations and under both normal and low-oxygen conditions. These data suggest that closure of the umbilical artery may be mediated by 5-hydroxytryptamine and thromboxane A(2).

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2003

The effect of mifepristone on the expression of steroid hormone receptors in human decidua and placenta: a randomized placebo-controlled double-blind study.

The objective of this study was to investigate the expression of steroid hormone receptors in human first trimester placenta and decidua and whether such expression was altered after mifepristone treatment. One hundred women who requested termination of pregnancy between 7 and 12 wk were randomly assigned to receive placebo or 200 mg mifepristone at 12, 24, and 48 h before suction evacuation of uterus. Immunohistochemistry was used to detect the expression of progesterone receptor, estrogen receptor, glucocorticoid receptor (GR), and androgen receptor. Progesterone receptor expression in both placenta and decidua tissues was not affected by mifepristone treatment. Estrogen receptor was identified in a decidual gland in only one sample. Androgen receptor was not expressed in either tissue. The expression of GR in decidual stromal cells was suppressed by mifepristone, and the effect was detectable at 12 h after administration. The expression of GR in decidual glands was not affected. In the placenta, the expression of GR in cytotrophoblasts and villous stromal cells was suppressed by mifepristone; the effect was detectable at 12 h and persisted at 48 h. In conclusion, the suppressed GR expression after mifepristone administration may be part of the mechanism of mifepristone in causing abortion.

Abortifacient Agents, Steroidal↗
PubMed2003

HBsAg carrier status and the association between gestational diabetes with increased serum ferritin concentration in Chinese women.

OBJECTIVE: To determine whether the high prevalence of hepatitis B surface antigen (HBsAg) carriage in our population can explain the previous observation of an association between increased maternal serum ferritin concentration and gestational diabetes in Hong Kong Chinese women. RESEARCH DESIGN AND METHODS: A retrospective study was performed on 767 nonanemic women with singleton pregnancy who had iron status assessed at 28-30 weeks. The result of the routine antenatal HBsAg screening was retrieved from patient records. The HBsAg-positive and -negative groups were compared for maternal characteristics, prevalence of gestational diabetes in the third trimester, prevalence of high serum ferritin and iron concentrations, and transferrin saturation, which is defined as a value in the highest quartile established by the measurements obtained from the HBsAg-negative group. RESULTS: The incidences of oral glucose tolerance test and gestational diabetes were significantly increased in the HBsAg-positive group. The HBsAg-positive women with gestational diabetes had significantly increased prevalence of high serum ferritin compared with the HBsAg-negative women, irrespective of the latter's gestational diabetes status. Multiple logistic regression analysis confirmed the independent association between HBsAg carrier status with gestational diabetes (relative risk 3.51, 95% CI 1.83-6.73) but excluded high ferritin as an independent factor. CONCLUSIONS: Our results indicate that maternal HBsAg carriage could explain in part the association between increased serum ferritin concentration with gestational diabetes in Hong Kong Chinese women, and that HBsAg carrier status is an independent risk factor for gestational diabetes.

Adult↗