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Biomedical subjects

T K Lau

Publications and source records attributed to T K Lau.

14 recordsLinked to original sources
PubMed1997

Pregnancy outcome after successful external cephalic version for breech presentation at term.

OBJECTIVE: Our purpose was to review the outcome of pregnancies after external cephalic version at term, in particular the incidence and indications of intrapartum cesarean section after successful external cephalic version. STUDY DESIGN: A prospective study was performed of 241 term pregnancies that had a total of 243 external cephalic versions. Each case with successful external cephalic version was matched to two control cases with cephalic presentation to compare pregnancy outcome. RESULTS: External cephalic version was successful in 169 attempts (69.5%), of which 7 (4.1%) reverted to breech presentation. There was one case of abruptio placentae and eight cases (3.3%) of transient fetal bradycardia after the procedure. Among those who had a successful external cephalic version, the incidence of intrapartum cesarean section was 16.9%, which was 2.25 times higher than that of the control group (p < 0.005). This large number of abdominal deliveries was due to a significantly higher incidence of fetal distress and dystocic labor. The incidence of augmentation of labor was also significantly higher in the study group (37.7% vs 27.6%, p < 0.05). CONCLUSION: Pregnancies after a successful external cephalic version at term are not the same as those with cephalic presentation. They are at higher risk of both dystocic labor and fetal distress and therefore require close intrapartum monitoring.

Adolescent↗
PubMed1997

A preliminary study on the effect of hormone replacement therapy on peripheral flow velocity in postmenopausal women.

Apart from predisposing to the formation of atherosclerosis in the coronary and cerebrovascular circulation, the menopause is also associated with an increased risk of developing peripheral vascular disease. The aim of this observational study was to determine whether the administration of hormone replacement therapy (HRT) had any effect on peripheral flow velocity in postmenopausal women. Changes in peripheral resistance were recorded in 11 healthy postmenopausal women using Doppler ultrasound. The pulsatility index (PI) of the brachial, radial, dorsalis pedis and popliteal arteries was measured before treatment and every 2 months after the commencement of HRT for 6 months. There was a significant decrease in the PI of the radial and dorsalis pedis arteries after HRT, and there were also reductions in the PI of the brachial and popliteal arteries which were not statistically significant. These changes persisted over the complete study period. Our findings suggest that the administration of HRT will have a beneficial effect on peripheral flow velocity in postmenopausal woman. These changes require confirmation in a larger controlled trial.

Adult↗
PubMed1996

Amnioinfusion for the prevention of meconium aspiration during labour.

The aim of this observational study is to review the outcome of prophylactic intrapartum amnioinfusion (AI) in pregnancies complicated by moderate to thick meconium-stained liquor (MSL). The labour and neonatal outcome of all 298 AIs performed over a 3-year period were compared to a matched-control group of patients whose labour was complicated by moderate or thick MSL but without AI. The incidence of moderate or thick meconium below the vocal cords of the neonate were significantly lower in the AI group (6.4% and 3.4%) compared with the control group (15.4% and 6.7%). The incidence of meconium aspiration syndrome in the AI group was half (1.7%) that of the control group (3.7%), although the difference did not reach statistical significance. There was a significant higher incidence of cardiotocographic abnormalities in the AI group (30.5% versus 14.7%), with higher incidences of Caesarean section and operative vaginal deliveries. The reduction in the incidence and thickness of meconium after AI was not accompanied by any statistically significant reduction in adverse fetal outcomes such as low Apgar scores, cord pH values, admissions to and duration of admission to the neonatal unit, or the incidence of meconium-aspiration syndrome.

Adult↗
PubMed1996

Fetal sex as a risk factor for fetal distress leading to abdominal delivery.

A retrospective analysis of perinatal information of 7,924 confinements in the calendar year of 1994 was performed to determine whether fetal sex was a significant risk factor for fetal distress in labour leading to abdominal delivery. The sex of the fetus (male) was a significant, independent, risk factor for Caesarean section (odds ratio = 1.26, 95% CI = 1.05 to 1.50). This increase was wholly attributable to the increased risk of having fetal distress in labour (odds ratio = 1.76, 95% CI = 1.32 to 2.34). Male fetuses are at higher risk of developing fetal distress during labour.

Cesarean Section↗
PubMed1996

A study of patients' acceptance towards vaginal birth after caesarean section.

Patients' acceptance towards vaginal birth after Caesarean section (VBAC) was studied in 99 women with previous Caesarean section. Their attitude was strongly related to the chance of success of VBAC. Only 53.3% of patients would accept VBAC if they were told that the chance of success was 70%. A history of vaginal delivery and a negative feeling towards previous operation were positively associated with acceptance of VBAC (p < 0.01), while convenience of elective Caesarean section and fear of vaginal delivery (even although most of them had had no vaginal delivery before) were the commonest reasons for refusal. The major caused of a negative feeling towards the previous Caesarean section were postoperative pain and a long recovery period. There was no significant negative effect on acceptance of VBAC if the previous Caesarean section was performed as an emergency operation for slow progress of labour or cephalopelvic disproportion.

Adult↗
PubMed1996

A randomized, double blind, controlled trial of tocolysis to assist external cephalic version in late pregnancy.

BACKGROUND: External cephalic version at term is not always successful. This trial was done to ascertain whether tocolysis has any effect on the success rate. METHODS: A randomized, double blind, controlled trial, with continuous paired sequential analysis. Fifty-one consecutive patients with a singleton fetus in a breech presentation between 36 and 38 weeks gestation, external version being attempted on each. Ritodrine infusion or placebo was infused before attempt at external cephalic version. SETTING: A university teaching hospital with 8000 confinements annually. RESULTS: Version was successful in 17 of the 25 patients given tocolysis, but in only eight of the 25 given placebo (p < 0.01). A positive benefit for tocolysis was shown after version had been completed in 10 pairs of patients. However the trial was continued until 25 pairs had been analyzed. The benefit deteriorated during analysis of the last 15 pairs suggesting that the initial benefit may reflect a learning curve for the procedure. CONCLUSION: Tocolysis is likely to improve the success rate of external cephalic version in late pregnancy, especially in nulliparous mothers or where doctors are learning the technique.

Adult↗
PubMed1995

Fetomaternal haemorrhage after external cephalic version at term.

The incidence of fetomaternal haemorrhage after external cephalic version was 1.8% in 167 patients. The occurrence of this complication was not found to be associated with difficult or unsuccessful version, or with any adverse perinatal outcome. We conclude that routine assessment of fetomaternal haemorrhage after external version is not necessary, except in rhesus negative women to detect the 2% in whom the routine dose of 500 iu (100 micrograms) of anti-D immunoglobulin is inadequate.

Female↗
PubMed1994

Lymphatic vaginal fistula after Wertheim-Taussig hysterectomy: a case report.

Significant vaginal discharge of clear fluid after Wertheim-Taussig hysterectomy with bilateral salpingo-oophorectomy is most often due to urinary fistula. Rarely, the same symptom may be caused by lymphatic fistula, which has not been reported previously. The differentiation between lymph and urine is simple. If this rare complication is not suspected, patients may undergo unnecessary invasive diagnostic procedures of the urinary tract.

Fallopian Tubes↗
PubMed1994

Uterine leiomyosarcoma associated with pregnancy: report of two cases.

Two cases of uterine leiomyosarcoma associated with pregnancy are reported. The outcome of the pregnancies were either second-trimester abortion or premature labor. Although the placentas were considered to be complete, both patients had foul-smelling vaginal discharge and tissue mass found at cervical os at the time of presentation. Both were treated initially by evacuation, followed later by total abdominal hysterectomy. One patient remained clinically well with no evidence of recurrence, while the other died 1 month after the diagnosis was made.

Adult↗
PubMed1994

A perinatal audit of stillbirths in a teaching hospital in Hong Kong.

In a 5-year period, the stillbirth rate in a teaching hospital in Hong Kong was 4.4 per 1,000 total births, which accounted for 61% of the perinatal deaths. The stillbirth rate was 5.8 times higher in twin pregnancies, and 17 times higher in triplet pregnancies. One quarter of the patients were nonbooked, and 14.5% had no antenatal care. The stillbirth rates were 3.8 and 8.0 per 1,000 among the booked and nonbooked cases respectively. The major causes of stillbirths were congenital abnormalities, haemoglobin Bart disease, abruptio placentae and gestational diabetes. No specific cause could be found in 46% of cases. There were 31 intrapartum deaths, of which 5 were potentially salvageable.

Abruptio Placentae↗
PubMed1993

Relationship between intrahepatic expression of hepatitis B viral antigens and histology in Chinese patients with chronic hepatitis B virus infection.

Hepatic cellular and subcellular expression of hepatitis B virus (HBV) antigens--HBsAg, HBcAg, and HBeAg--in 143 Chinese patients with chronic HBV infection were studied by immunohistochemical techniques. Nuclear expression of HBcAg and nuclear and cytoplasmic expression of HBeAg showed a secular trend decreasing from the carrier state and chronic persistent hepatitis (CPH), through chronic active hepatitis (CAH), to cirrhosis with or without hepatocellular carcinoma. In contrast, cytoplasmic HBcAg expression was significantly greater in patients with CPH and CAH (P < .0108). In addition, cytoplasmic HBcAg correlated significantly with lobular activity, portal inflammation, and hepatitic activity (P < or = .007). Expression of cytoplasmic HBcAg also exceeded cytoplasmic HBeAg and nuclear HBcAg in liver specimens showing significant damage (P < .038). HBsAg, however, showed no secular trend and was not related to liver histology. The authors' findings support the theory that HBcAg is also the viral target antigen for immune-mediated liver damage in Chinese patients with chronic HBV infection.

Adolescent↗
PubMed1991

Automated detection of breast tumors using the asymmetry approach.

A method for automated detection of breast tumors in mammograms is presented. The method uses the asymmetry principle: Strong structural asymmetries between corresponding regions in the left and right breast are taken as evidence for the possible presence of a tumor in that region. Asymmetry detection is achieved in two steps. First, mammograms are aligned, compensating for possible differences in size and shape between the two breasts. Second, asymmetry between corresponding positions is determined using a combination of several asymmetry measures, each responding to different types of asymmetries. Results obtained with a set of mammograms indicate that this method can improve the sensitivity and reliability of systems for automated detection of breast tumors.

Breast Neoplasms↗
PubMed1991

Application of hepatitis B virus (HBV) DNA sequence polymorphisms to the study of HBV transmission.

Short sequences in hypervariable regions of the hepatitis B virus (HBV) genome can be used to identify different strains, providing a novel approach to the study of HBV transmission. The nucleotide sequence in positions 2551-2650 (1:EcoRI site) was determined for serum HBV DNA from 96 Chinese children living in Hong Kong and from 38 of their parents. HBV DNA was extracted and sequenced after amplification with the polymerase chain reaction, using as primers oligonucleotides corresponding to two conserved sequences. Among 82 unrelated children, 32 HBV DNA variants were present. One sequence was present in 33 children and 31 variants were found among the other 49. Siblings within each of nine families had the same variant; in three families siblings had different variants. Six of the eight fathers and 28 of the 30 mothers had HBV DNA sequences identical to those of their offspring. A total of 34 variants were found among the 134 individuals. The hypothesis of random assortment of sequences in parents and children was rejected (P less than .00005). Thus, this new approach proves the occurrence of intrafamilial transmission of HBV among Chinese.

Adult↗