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Biomedical subjects

S Arulkumaran

Publications and source records attributed to S Arulkumaran.

At least 91 records · Page 5Linked to original sources

Coagulation activation, fibrinolysis and inhibitors in neonates.

Enhanced coagulation activation with reduced antithrombin III (ATIII) activity was seen in healthy neonates. Although systemic tissue plasminogen activator (t-PA) and urokinase-like plasminogen activator (u-PA) levels showed no significant differences from normal adults, enhanced fibrinolysis was indicated by elevated D-dimer and low plasminogen levels in the neonates in this study. Enhanced fibrinolysis observed was countered by elevated plasminogen activator inhibitor-I (PAI-1) levels, a trend similar to that observed in the amniotic fluid during labour. The elevated PAI-1 level seen in neonates may have a beneficial effect in preventing haemorrhage in the neonatal period. The haemostatic and fibrinolytic mechanisms studied in normal pregnancy neonates were similar to neonates born to gestational diabetes mellitus (GDM) mothers. Further studies need to include neonates with poor outcome and low Apgar score to assess their haemostatic status.

Adult↗

Identification of seven novel mutations in LH beta-subunit gene by SSCP.

Seven new point mutations have been identified from LH beta-subunit gene by PCR-mediated SSCP, and sequencing. One mutation was found changing amino acid from Gln102 to Ser102. The remaining six mutations, which did not change the codings, were in complete linkage disequilibrium. SSCP can be used in the diagnosis of LH-related disorders.

DNA Mutational Analysis↗

Management of non-immune hydrops: 8 years' experience.

During a period of 8 years (1985-92), 100 fetuses were diagnosed to have non-immune hydrops on the basis of ultrasonographic findings and absence of rhesus isoimmunization. Both the mother and the fetus were thoroughly evaluated by a set protocol that included a detailed fetal abnormality scan with echocardiography and fetal blood sampling. A cause for non-immune hydrops could be identified in 81% of the fetuses. Cardiovascular abnormalities (23%) and alpha(1)-thalassemia (22%) were almost equally common etiological factors in the South-East Asian population under investigation. A chromosomal abnormality was detected in 10% of the fetuses with non-immune hydrops. Twenty-six fetuses were found to be suitable for in utero therapy. In utero therapy included one or more of the following: (1) fetal intravascular blood transfusion; (2) direct fetal drug therapy; and (3) fetal pleuroamniotic shunting. Eighteen of the 26 babies (69.2%) were alive and well at 1 month after delivery. It is concluded that in well-selected cases appropriate in utero fetal therapy can lead to significant improvement in fetal salvage.

Evaluation Studies as Topic↗

Fetal and neonatal haemodilution associated with multiple placental chorioangioma: case report.

A pregnancy with polyhydramnios and abnormal antepartum fetal heart rate pattern was found to have multiple placental haemangiomas. Multiple placental haemangiomas can give rise to fetal cardiac failure due to a hyperdynamic circulation or fetal anaemia either due to haemodilution or possibly destruction of blood cells in the chorioangioma. Whether fluid restriction with or without diuretics or blood transfusion is the correct form of treatment of neonatal cardiac failure in such a case is discussed.

Adult↗

Assessment of fetal health should be based on maternal perception of clusters rather than episodes of fetal movements.

OBJECTIVE: To determine the level of correlation between mother and machine detected episodes and clusters of fetal movements and their association with fetal heart rate acceleration. METHODOLOGY: An observational study conducted on health pregnant women between 29-40 weeks gestation who were admitted in spurious labour to the Department of Obstetrics and Gynaecology, National University Hospital, Republic of Singapore. A continuous record of fetal heart rate and fetal movement was obtained using the fetal actocardiograph. Fetal movements felt by mother were also noted. If a continuous series of fetal movements were perceived over a period of 15 secs or more it was termed clusters of fetal movement. The presence or absence of acceleration in relation to these movements were noted. RESULTS: There was a highly significant correlation between mother and machine in detection of clusters of fetal movements (r = 0.77, p < 0.001); for episodes of fetal movements, the correlation was weaker (r = 0.23, p < 0.05). All clusters of fetal movements perceived by the mother were recorded by the machine and were associated with fetal heart rate accelerations. Two or more accelerations within 3 minutes of the fetal movements were seen with 87.8% of clusters felt by mother compared with 66.7% detected by the machine (p = 0.01). In the 2,263 minutes of recording in 42 women, a cluster of fetal movements was felt at least every 25 minutes by the mother. CONCLUSION: Maternal perception of 1 or 2 clusters of fetal movements in 30 to 60 minutes may be as reliable as a non-stress test in reassuring good health. It would be less time consuming than the traditional count to 10 fetal movement chart and a more reliable indicator of fetal health than counting episodes of fetal movements. Thus, our study suggests that clusters rather than episodes of fetal movements should be considered for evaluating fetal health based on fetal movements.

Adult↗

Audible in utero sound caused by the ultrasonic radiation force from a real-time scanner.

While investigating in utero sound levels during vibro-acoustic stimulation on the maternal abdomen it was noticed that noise level increased when the real-time ultrasonic scanner beam was directed at the sensing hydrophone. The noise was recorded and later analysed for frequency content and waveform. It appeared related to the scanning and frame rate frequencies of the scanner used. Sounds may originate from radiation pressure produced when the ultrasound beam is absorbed by tissue or reflected from bone or the metal hydrophone. This implies that although ultrasound cannot be heard per se, any modulation of its intensity will produce vibrations in the maternal tissues or reflecting structures such as skull bone, and especially stapes, malleus and incus, that would be heard as sound by the fetus. The intensity of the sound produced varied with orientation of the transducer beam and this may itself produce a stimulation. Based on our recordings (Fig. 1), it was calculated (please see Appendix) that the fetus would hear a sound corresponding to 84dB noise pressure level in air.

Acoustic Stimulation↗

Mild cervical atypia: a management dilemma.

This study examined 117 patients with mild cervical atypia or atypical squamous cells of uncertain significance; it was found that 25% had histologically proven CIN lesions by colposcopically-directed punch biopsy or cone biopsy. 18% were found to have at least CIN 2 lesions and there was 1 case of invasive cancer. These data strongly support the recommendation of early colposcopic referral in patients with mild cervical atypia.

Adolescent↗

A comparison between visual estimation and laboratory determination of blood loss during the third stage of labour.

A prospective study was conducted to compare the accuracy of visual estimation of blood loss (EBL) at delivery with laboratory determination of measured blood loss (MBL). It showed that EBL tends to be clouded by the conventional teaching that blood loss at delivery is usually between 200 to 300 mL. Women with MBL up to 150 mL were overestimated and the best correlation was in women with MBL between 150 to 300 mL. There was a tendency to underestimate blood loss when the MBL was between 301 to 500 mL. Of the 9 women with a primary postpartum haemorrhage, only one was correctly diagnosed as such and 3 women were estimated to have blood losses of at least 500 mL but the measured blood losses were all lower. It was concluded that visual estimation of blood loss is inaccurate, especially at the extremes of MBL and that primary postpartum haemorrhage is not detected by visual estimation of blood loss, unless there are associated signs of haemodynamic instability.

Female↗

Correlation of total uterine activity to blood loss in the third stage of labour.

In 27 women, uterine activity in the third stage of labour was correlated with blood loss measured quantitatively during the same period of time. Myometrial activity was reflected by total intrauterine pressures measured using a Gaeltec catheter tipped pressure transducer inserted transcervically within 5 min of delivery of the placenta. Blood loss over the same 2-hour period was collected on absorbent paper and measured in the laboratory by colorimetric measurement of the haemoglobin content. As total uterine activity in the third stage of labour decreases total blood loss increases, but there is a poor correlation of uterine activity to total blood loss over the same period of time, probably because of biological variations in myometrial activity in normal women.

Female↗

Randomised controlled trial of methyldopa and isradipine in preeclampsia--effects on uteroplacental and fetal hemodynamics.

This is a prospective randomised controlled study in 21 women admitted with preeclampsia in the third trimester. The mean arterial blood pressure decreased by 11.1 mmHg (95% confidence interval -14.9 to -7.3 mmHg) in the methyldopa group, and by 9.3 mmHG (95% confidence interval-14.4 to -4.2 mmHG) in the isradipine group. The maternal heart rate decreased by 6.9 beats per min (95% confidence interval -11.6 to -2.2 bpm) during methyldopa treatment, and by 2.5 beats per min (95% confidence interval -9.2 to 4.3) during isradipine treatment. Pulsatility index in maternal and fetal vessels was not affected by either of the two drugs. The birth weight and placental weight and neonatal outcome were similar and uneventful. The hypotensive effect was similar for methyldopa and isradipine. Except reduced maternal heart rate on methyldopa, fetal and uteroplacental hemodynamics were not altered during treatment of preeclampsia with methyldopa or isradipine.

Antihypertensive Agents↗

Search for the most predictive tests of fetal well-being in early labor.

The aim of the study was to evaluate the admission CTG alone and in combination with the following tests: fetal acoustic stimulation test (FAST), maternal perception of sound provoked fetal movement (mpSPFM), amniotic fluid index (AFI), and umbilical artery doppler studies in early labor. 1092 singleton pregnancies in cephalic presentation, and with intact amniotic membranes at 37 weeks gestation or more, were admitted in early labor to the labor ward at the National University Hospital, Singapore. Admission tests were performed, and labor managed according to established labor ward protocol. Of all the tests performed, only the results of the admission CTG and color of the amniotic fluid were known to the obstetrician. If the admission CTG is normal, AFI is > 5 cm and there is an acceleratory responses to FAST the incidence of fetal distress is low. In the presence of a reactive admission CTG and in the absence of thick meconium, fetal heart rate response to FAST and the AFI provided a better selection of the high risk fetus that would require closer monitoring or early delivery. When the admission CTG was suspicious, FAST, AFI, and blood flow velocity waveform studies may allow more confident prediction of the ability of the fetus to withstand the stresses of labor.

Acoustic Stimulation↗

Evaluation of auditory system in preschool children whose mothers had mid-second trimester amniocentesis.

A prospective study was conducted in the Otorhinolaryngology department, National University Hospital, Singapore to evaluate the effects of mid-trimester amniocentesis on the auditory system in preschool children of about four years of age. Fifty-nine children whose mothers had mid-second trimester amniocentesis and 63 children (control group) whose mothers did not have amniocentesis in that pregnancy were recruited. The children were subjected to audiological tests to assess hearing impedance abnormalities. The incidence of prematurity, neonatal admissions, ear and respiratory infections, auditory function, speech and language development in children were evaluated because these factors have a bearing on the development of auditory impedance abnormalities. There was no significant increase in the neonatal admission rates, impairment of speech and language development and auditory function in children whose mothers had mid-second trimester amniocentesis compared with the control group whose mothers did not have amniocentesis. An incidental finding in this study was an increased incidence of respiratory illnesses in the children in the amniocentesis group (57.6%) compared with the control group (30.1%). This needs further evaluation with a properly designed study.

Acoustic Impedance Tests↗

Incidence of chromosomal abnormalities in 153 pregnancies with ultrasound detected fetal abnormalities.

One hundred and fifty-three patients with fetal abnormalities diagnosed on ultrasound were karyotyped between January 1992 and December 1993. There were 19 (12.4%) fetuses with chromosomal abnormalities. The risk of chromosomal aberrations in the malformed fetuses were increased in the presence of intrauterine growth retardation (15.4%), oligohydramnios (20%) and polyhydramnios (25%). Fetal karyotyping is thus essential in the management of such pregnancies.

Chromosome Aberrations↗

Premature rupture of membranes in nulliparas at term with unfavorable cervices: a double-blind randomized trial of prostaglandin and placebo.

OBJECTIVE: To determine whether the use of a prostaglandin (PG) E2 3-mg pessary followed by a delay of 12 hours before stimulation of labor with oxytocin improves obstetric outcome compared with the use of a placebo pessary. METHODS: One hundred fifty-five nulliparas at term with poor cervical scores (modified Bishop score below 6 of 10) and premature rupture of membranes (PROM) were recruited for this double-blind, placebo-controlled randomized trial. On admission to the study, either a PGE2 pessary or an identical-appearing placebo pessary was inserted into the posterior fornix. If labor did not start in the next 12 hours or if symptoms and signs of infection were evident, labor was induced with oxytocin infusion. Assignment was unblinded at the end of the study, and details of the labor and maternal and neonatal outcome in women who received a PG pessary were compared with those who received a placebo pessary. RESULTS: Women receiving a PG pessary were significantly less likely to require stimulation of labor at the end of 12 hours than were those given a placebo pessary (37 versus 58%, P = .002). The mean time between admission to study and delivery was significantly shorter in the PG group compared with the placebo group (15 versus 19 hours, P = .01). The rate of cesarean delivery was not statistically different in the two groups (13.9% with PG versus 15.8% with placebo). CONCLUSION: In nulliparas with poor cervical scores who present with PROM at term and no evidence of infection or obstetric complications, use of a PGE2 pessary resulted in more women establishing labor earlier, with a resultant reduction in the admission-to-delivery interval, compared with the use of a placebo pessary. The cesarean delivery rates in the two groups were similar, and there were no significant differences in neonatal outcome.

Cervix Uteri↗

Continuous maternal glucose infusion during labor: effects on maternal and fetal glucose and lactate levels.

Fetal and neonatal glucose and lactate levels and acid-base balance after continuous maternal infusion of 5% dextrose at 180 mL/h (9 g/h) was compared with 0.9% saline solution in a prospective, randomized study from selected monitored labors. An infusion of 5% dextrose produced significantly increased glucose levels in maternal (p < 0.01), cord artery (p < 0.01), and cord vein (p < 0.001) blood. An increased maternal insulin level was also present (p < 0.05), but no differences in cord insulin levels were observed. beta-Hydroxybutyrate was lower in maternal (p < 0.05) and cord vein (p < 0.01), but not in cord artery blood, after maternal dextrose infusion. No significant changes occurred in blood lactate levels between the two groups in either mother, fetus, cord, or neonate. Acid-base balance in cord blood did not differ between the two groups. Maternal infusion of 5% dextrose at 180 mL/h (9 g/h), compared with saline solution, produces higher glucose levels in both mother and fetus, but increased insulin concentrations only in the mother. Dextrose infusion also lowers beta-hydroxybutyrate in maternal and cord vein blood. No differences were seen in lactate levels or cord acid-base balance. Both regimens seem safe according to risks for lactacidosis and neonatal hypoglycemia in the normoxemic, normal size fetus.

3-Hydroxybutyric Acid↗

Prelabour rupture of membranes to delivery interval related to the incidence of maternal and neonatal infection.

OBJECTIVE: To assess the infectious morbidity associated with prelabour rupture of membranes (PROM) to delivery interval, and the incidence of maternal and neonatal infection in a population managed by either immediate stimulation or by overnight conservatism. METHOD: A retrospective study of 117 women admitted with PROM to the labour ward in the National University Hospital, Singapore, in the period between June 1990 and May 1991, and who were managed by immediate stimulation or by stimulation after overnight conservatism. Statistical analysis was performed using Chi-square and Student's t-test. RESULTS: More than one third of infants whose mothers had ruptured membranes for > 48 hrs had signs of neonatal infection, compared with an incidence of 8.8% and 8.9%, respectively for those with an interval of < 12 hrs and 12-24 hrs between PROM to delivery. Group B streptococcal infection was a major cause of neonatal infectious morbidity. Clinical evidence of maternal infection occurred in 3 of the 117 women; these patients had an interval between rupture of membranes and delivery of between 24-76 hrs. CONCLUSIONS: Prolongation of PROM to delivery interval for > 48 hrs increases the incidence of infection. Conservative policy of management of PROM at term should aim to deliver the babies < 48 hrs after PROM. The difference in maternal and neonatal infection rates were not significant in the group treated with a policy of overnight conservatism compared with the group in whom labour was stimulated immediately on admission.

Bacterial Infections↗