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Biomedical subjects

R L TambyRaja

Publications and source records attributed to R L TambyRaja.

17 recordsLinked to original sources
PubMed2000

Preterm labour.

Spontaneous preterm labour remains a major obstetric problem because of the high incidence of neonatal mortality or long-term handicap associated with it. The drugs available for the management of preterm labour are poorly effective and have potentially serious side-effects for the mother or fetus. In recent years, there has been a remarkable increase in the knowledge of the biochemical mechanism underlying uterine quiescence and contractility. Many of the G protein-coupled receptors that participate in the regulation of myometrial activity have been cloned and characterized, and their intracellular signalling pathways have been elucidated. The role of G protein receptor kinases in uterine tachyphylaxis is better understood. New developments in our understanding of the cellular mechanisms involved in uterine contractions in idiopathic and infection-associated preterm labour are expected, which will lead to better, more selective therapy for this problem. However, much research remains to be done before the mechanism of human parturition is fully understood.

Chorioamnionitis↗
PubMed2000

Loss of myometrial oxytocin receptors during oxytocin-induced and oxytocin-augmented labour.

Oxytocin is used widely for the induction and augmentation of labour, but there is little information about the dynamics of oxytocin receptors in human myometrium during parturition, and the possible effect of oxytocin infusion. This information is important because G protein-coupled receptors, such as the oxytocin receptor, undergo desensitization after prolonged or repeated stimulation. The concentration of myometrial oxytocin receptors and the steady state of its mRNA were measured in patients undergoing Caesarean sections before or during spontaneous or induced labour. The concentration of receptors before labour was 477 (175-641) fmol mg(-1) protein (median, quartile range), and decreased to 140 (72-206; P < 0.05) and 118 (69-75; P < 0.01) fmol mg(-1) protein during prolonged oxytocin-augmented and oxytocin-induced labour, respectively. The corresponding oxytocin receptor mRNA concentrations decreased by 60- and 300-fold, respectively. The decrease in receptor binding and mRNA in women receiving oxytocin infusion indicates that homologous receptor desensitization occurs in vivo.

Analysis of Variance↗
PubMed1999

Observations on obstetric practice in a multicultural setting.

Singapore provides a rich environment for investigations into ethnic differences in pregnancy outcome, as it is populated by Malays, Indians, and Chinese. Years of clinical practice and obstetric research in this environment have affirmed the observation that many factors interact in determining length of gestation and birth weight, and that these factors have differential affects among these three different ethnic groups. Although technological advances have furthered our understanding of obstetrical outcomes and provided essential tools to promote the survival of premature infants, the persistent use of uniform growth standards hampers our ability to assure positive outcomes for women of different ethnicity. Recognition of ethnic differences has resulted in declines in certain negative pregnancy outcomes for women in Singapore. The development of race-specific uterine growth curves will enhance the provision of perinatal care for all women.

China↗
PubMed1993

Fetal salvage in maternal systemic lupus erythematosus.

Fifty-two pregnancies in 30 patients with systemic lupus erythematosus were studied prospectively. There were two spontaneous abortions, two therapeutic terminations for active disease, two intrauterine deaths before 28 weeks and one stillbirth. Forty-five (86.6%) pregnancies had a successful outcome. Five patients had renal involvement before or during pregnancy whilst 12 (23%) had preeclampsia. Placental insufficiency and intrauterine hypoxia contributed to a high Caesarean section rate (44%). The selection of patients for pregnancy, optimal medical care, antenatal monitoring and intensive neonatal care have improved fetal salvage in this condition.

Abortion, Spontaneous↗
PubMed1989

Current concepts in the management of preterm labour.

Prematurity remains the major cause of perinatal mortality and morbidity in Singapore. Prevention of prematurity is therefore of vital importance. Epidemiological methods using historical variables have been superseded by ongoing pregnancy factors including work, exercise and cervical dilatation. PGF levels bear a positive correlation to duration and cervical dilatation but are not elevated at onset. PGE production is high in ruptured membranes. Progesterone and relaxin are potent inhibitors before labour. Infection must play an important role in developing countries as organisms not thought of to be pathogenic produce phospholipase A2. For prediction, cervical assessment and topography are proving important. In view of the dangerous side effects of tocolytic drugs and the difficulty in diagnosis of preterm labour, absence of fetal breathing is a useful index of progressive labour. In those labours that are advanced, whether to allow vaginal delivery or not will be determined by the presentation and condition of the fetus. The complementary role of other drugs to reduce morbidity from hyaline membrane disease and intraventricular haemorrhage is being studied. Fetal acidosis should be avoided and the infant delivered without trauma under optimal circumstances. In utero transfer to a facility with neonatal intensive care carries a better prognosis for the baby.

Delivery, Obstetric↗
PubMed1985

Failed induction of labour.

Over a 15-month period 1,057 consecutive inductions of labour were performed representing a 10% induction rate; 174 (16.5%) of these patients were delivered by Caesarean section of which 74 (7.0%) were for failed induction of labour, 58 (5.5%) for fetal distress, 19 (1.8%) for cephalopelvic disproportion, 6 for malposition and 17 for other reasons. The mean cervical score at induction of labour was 5.7 and 5.5 for cephalopelvic disproportion (CPD) and malposition respectively but was 4.0 for failed induction. The mean cervical dilatation at the time of Caesarean section was 5.7 cm and 6.6 cm for CPD and malposition respectively whereas it was 3.5 cm for failed induction. Mean maximum dose of oxytocin was 19.2 milliunits per minute (mu/min) and 22.5 mu/min for CPD and malposition respectively whereas it was 24.7 mu/min for cases of failed induction. Nulliparas with a cervical score of 3 or less had a 65.4% Caesarean section rate of which more than two-thirds were for failed induction of labour. Analysis of indications for induction of labour revealed that a fair number of inductions had debatable obstetric indications. Tailoring induction of labour to the cervical score and indication might reduce the Caesarean section rate for failed induction of labour. Rational management to ensure an adequate dose of oxytocin and sufficient time in the first stage of labour is important. Failed induction of labour may be differentiated from failure of labour progress due to CPD or malposition.

Adult↗
PubMed1984

Factors contributing to a reduction of twin perinatal mortality in Singapore.

A total of 204 cases of twin pregnancy occurred between 1970 and 1972 have been compared with 102 cases occurred between 1976 and 1978. During the interval of time, specialised care was instituted for the early diagnosis and management of twins. The incidence of twin pregnancy in Singapore decreased from 1:131 to 1:141 pregnancies. With a background of improved socioeconomic conditions and obstetric care, there has been a dramatic decline in perinatal mortality from 76.4 to 29 per 1000. In undiagnosed cases, the perinatal mortality of the first vs the second twin in the earlier group was 64.4 vs 93.6 per 1000. No such difference was observed in the later period, with the average birthweights of twins being significantly higher. The principles of our antenatal supervision, antenatal tocography , and management are presented and the value of early diagnosis, bedrest, and tocolytic therapy discussed. The reduced perinatal mortality and morbidity gives evidence of an improvement in prematurity and augmented intrauterine growth.

Adult↗
PubMed1982

Research and development in obstetrics & gynaecology in the Department of Obstetrics & Gynaecology at the National University of Singapore.

This is a review of the research and achievements of the Department of Obstetrics and Gynaecology, National University of Singapore since 1949. The research activities reviewed are Fertility Control, Subfertility, Reproductive Endocrinology, In-Vitro Fertilization, Trophoblastic Disease, Prostaglandins and Perinatal Medicine. The University Department has kept abreast with the Singapore norm of two-child families by providing the most sophisticated technology and expertise. The perinatal mortality and stillbirth rates have been reduced to 11 and 6 per thousand births. Prostaglandin research in the Department includes an investigation of the involvement of these substances in various physiological processes, pharmacological studies with different prostaglandins and development of clinical applications. Between 1974 and 1981 we had studied 12 intrauterine contraceptive devices, both on a departmental basis and in conjunction with international agencies. The newer medicated devices have proved to offer significant advantages over the original inert plastic configuration. Metabolic changes in Singapore women on the oral pill and injection Depoprovera were studied. Impaired glucose tolerance and raised fasting total lipids were found in women on the pill. Marginal changes in carbohydrate metabolism only were found in women on injection Depoprovera. Hypercoagulation changes in the blood occurring in Singapore women varied with the dose of the synthetic or natural oestrogen medication. Initially, the fibrinolytic activity was enough to compensate for these changes; however after two years there were signs of decompensation. Progestogens affect coagulation via their influence on the liver functions. Hypercoagulation changes also occurred in pregnancy and was of a greater magnitude than oestrogen or progestogen medication. In many obstetric disorders, including hydatidiform mole, there was evidence of intravascular coagulation. The introduction of endocrine function tests has greatly improved patient care in our Department, in particular those related to endocrine disorders. Application of the immunoassays to basic research has shown that physiological levels of oestradiol exert a negative feedback effect on both FSH and LH secretions in men. The greater suppression of LH than of FSH secretion by pharmacological doses of estradiol is possibly due to different control mechanisms in the pituitary for the synthesis and release of both gonadotrophins. Physiological level of testosterone per se has a definite negative feedback effect on the secretion of LH but not on FSH. Pharmacological doses of the 5-alpha-reduced metabolites of testosterone have been shown to suppress both LH and FSH indicating that some of the actions of testosterone could be medicated by these metabolites of which the 3 alpha-androstanediol and 3 beta-androstanediol are the more likely candidates.

Academic Medical Centers↗
PubMed1981

Fenoterol: an effective agent for the postponement of preterm birth.

Ninety patients in preterm labour were treated with a new sympathomimetic drug fenoterol hydrobromide (partusisten). Labour was inhibited in 80 (88.9 percent) for a minimum of 24 hours, and pregnancy continued until at least 36 weeks of gestation in 52 (57.8 percent) patients. The average duration of intravenous fenoterol needed for successful therapy was 16.4 hours, and the majority (56.2 percent) settled with a maintenance dose of 2 to 3 microgram min-1. The minimum prolongation index associated with full success was 3.36. Side-effects included palpitations and tachycardia. Serious congenital abnormalities were seen in one of five perinatal deaths but was not attributable to drug therapy.

Adult↗
PubMed1978

Plasma estradiol as a predictor of preterm labor.

Studies have shown a rapid rise of plasma estradiol-17beta in the maternal circulation before the occurrence of preterm labor. We have attempted to perform a linear regression analysis of the data from normal pregnancies and to set up a 95% upper prediction limit for the normal range of the estradiol level for each week of gestation. The prediction limits were reasonably good, with only five (13%) false negatives. False negatives tend to occur only in late pregnancy.

Estradiol↗
PubMed1977

Endocrinology of normal pregnancy and premature labour.

Peripheral plasma levels of the biologically important hormones of pregnancy--plasma oestradiol 17 beta, plasma oestriol, plasma progesterone, human placental lactogen (hPL) and human chorionic gonadotrophin (hCG) have been measured serially in a control group of 10 normal women who delivered at term +/- three days. A second group of patients were similarly studied when admitted in premature labour and the levels compared with the control group. The levels of all hormones except human chorionic gonadotrophin increased till 37 weeks. After the 30th week, the increase of oestriol was steeper than oestradiol and hPL. The hormone profile of the maternal plasma is a good index of feto-placental function. The hPL levels which heralded the increase in endocrine function of the feto-placental unit were also elevated in premature labour, suggesting a casual relationship of significance. Levels of plasma oestradiol in premature labour were considerably higher than in the control study and suggests an endocrine basis for premature labour of hitherto unknown aetiology.

Adult↗
PubMed1977

F prostaglandin levels in amniotic fluid in premature labour.

The concentration of prostaglandin F (PGF) in amniotic fluid was measured by radioimmunoassay in 27 patients admitted in premature labour. There was a strong correlation between PGF levels in amniotic fluid and both cervical dilatation (r = 0.81; P less than 0.001) and duration of labour (r = 0.79; P less than 0.001). Cervical dilatation greater than 7 cm was associated with levels exceeding 2000 pg/ml. When contractions were present for less than one hour, levels of PGF were below 50 pg/ml. Low levels of PGF were found in amniotic fluid from a separate group of three patients, of whom two had cervical incompetence. It is concluded that the onset of premature labour is not associated with elevated levels of PGF in amniotic fluid. During premature labour, concentrations rise to an extent comparable to that observed in labour at term.

Amniotic Fluid↗
PubMedDate not supplied

Postponement of preterm birth with salbutamol.

Salbutamol was administered intravenously and orally to 58 patients who were admitted to the hospital because of premature labor. Pregnancy was postponed until at least 36 weeks' gestation in 34 of these patients. The success of this therapy was measured by a parameter of the prolongation index which was inversely related to the Bishop's score. This measurement was highest among patients in whom pregnancy was successfully prolonged.

Administration, Oral↗