Biomedical subjects
S Arulkumaran
Publications and source records attributed to S Arulkumaran.
Factors influencing recruitment and retention of academic staff in South-East Asia.
South-East Asia has a number of developing and developed countries. The economic standings of these countries are different and influence the number of staff in each academic department. The quantum of clinical work they are expected to perform and the remuneration vary enormously. The retirement age, facilities for research and criteria for promotion are different. The health care delivery system, the financial status and outlook of the universities also differ. These factors operate differently in the South-East Asian countries and determine the recruitment and retention of academic staff.
Psychosocial support or active management of labour or both to improve the outcome of labour.
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Umbilical artery blood gas and lactate in healthy newborns.
This study aimed to establish the normal range of umbilical artery pH, pCO2, base deficit and lactate in normal term and preterm newborn. Umbilical artery pH, pCO2, base deficit and lactate was measured in 637 newborn babies. The study included 555 babies at term with Apgar score equal to or more than 7 at 5 minutes, not requiring assisted ventilation and not admitted to the neonatal unit (NNU), as well as 47 preterm babies with Apgar score equal to or more than 7 at 5 minutes who were admitted to the NNU for observation only because of prematurity. Data was presented as mean and SD. Statistical analysis was done by t-test and simple linear regression analysis. In the newborn at term mean umbilical artery blood gas and lactate were as follows; pH = 7.25 (+/- 0.08), pCO2 = 45.66 (+/- 1.88) mmHg, base deficit = 7.69 (+/- 3.88) mEq/L, lactate = 2.96 (+/- 1.8) mMol/L. In preterm newborn the values were; pH = 7.25 (+/- 0.04), pCO2 = 51.78 (+/- 13.00) mmHg, base deficit = 5.29 (+/- 1.87) mEq/L, lactate = 2.55 (+/- 1.87) mMol/L. The range of umbilical artery blood gas and lactate parameters in term and preterm fetuses with good neonatal outcome were derived. There was a statistically significant difference in pCO2 and base deficit between term and preterm newborn. There was no linear correlation between lactate, pH, pCO2, base deficit and fetal glucose respectively in term or preterm infants.
Lactate, lactate/pyruvate ratio and catecholamine interrelations in cord blood at delivery in complicated pregnancies.
The interrelationships between lactate, lactate/pyruvate (L/P) ratio and catecholamines (CA) in cord artery and vein blood were studied in 56 pregnancies who had complications in the antenatal period or during labour. This group of babies had higher CA levels and were more acidaemic than fetuses after normal pregnancies and labour. There were stronger correlations between lactate and noradrenaline (NA) (R = 0.56, P < 0.001), adrenaline (A) (R = 0.41, P = 0.002) and dopamine (DA) (R = 0.42, P = 0.001) in cord artery blood, than previously reported for normal deliveries. Correlations between L/P ratio and CAs were also significant, although weaker. Multiple regression analysis, using cord artery lactate as the dependent variable, revealed significant correlations for pH (P = 0.01) and pyruvate (P < 0.001) but not for the CAs. The subgroups with high lactate (> 75th centile) had significantly higher NA (P = 0.007) and DA (P < 0.001) in cord artery and NA (P < 0.001) and A (P < 0.001) in cord vein blood, as compared with the subgroup who had lower lactate concentrations. We conclude that fetal hypoxia induces fetal CA production as well as anaerobic metabolism with lactate production. However, the adrenergic stimulation seems not to contribute significantly to the fetal lactate production.
A new molecular variant of luteinizing hormone associated with female infertility.
OBJECTIVE: To investigate whether the newly described G1502 to A1502 mutation in exon 3 of the LH beta-subunit gene, causing the amino acid substitution of Ser102 for Gly102, is related to female infertility. DESIGN: Screening of fertile and infertile women for the G1502 to A1502 mutation in the LH beta-subunit gene. SETTING: Clinics and laboratories of the National University Hospital obstetrics and gynecology department, Singapore. PATIENT(S): Two hundred twelve healthy fertile women; 40 infertile women with menstrual disorders, polycystic ovary syndrome, and endometriosis; and 12 women with idiopathic infertility. INTERVENTION(S): Exon 3 of the LH beta-subunit gene was analyzed using polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP), and PCR-mediated direct DNA sequencing. MAIN OUTCOME MEASURE(S): The PCR products of patients were analyzed by RFLP, and the results were compared with those of fertile controls. DNA sequencing radiographs were compared between two mutation-bearing patients and four controls. RESULT(S): The mutation was identified in only two infertile women with endometriosis; other women studied were found to be negative for this mutation. CONCLUSION(S): The missense mutation in the LH beta-subunit gene may be implicated in female infertility, possibly endometriosis-associated infertility in some women.
Arterial embolization for bleeding following hysterectomy for intractable postpartum hemorrhage.
Angiographic embolization is a well documented technique that has been utilized for controlling pelvic hemorrhage. A case is described of a 41-year-old para 3 woman with intractable bleeding following a cesarean hysterectomy for postpartum hemorrhage due to uterine atony and coagulopathy. On angiogram, no bleeding was seen from the uterine vessels. An injection of dye above the origin of the gonadal vessels showed persistent hemorrhage from the left ovarian artery. This report illustrates the importance of intensive resuscitation and supportive measures, and the value of angiographic embolization after failed surgery. It also emphasizes the need to locate the exact bleeding vessel on angiography for embolization to be successful.
Lactate and acid-base balance at delivery in relation to cardiotocography and T/QRS ratios in the second stage of labour.
OBJECTIVE: To compare foetal electrocardiogram (T/QRS ratio) and cardiotocography (CTG) during the second stage of labour with lactate and acid-base balance in cord artery blood at delivery. DESIGN: Forty-six parturients delivered at the National University of Singapore were monitored during the second stage of labour with T/QRS ratios and CTG. At delivery blood from a segment of clamped cord was sampled for lactate and acid-base balance analyses. The Spearman Rank correlation, the Mann Whitney U-test and the Kruskal Wallis ANOVA were used when appropriate. RESULTS: Maternal pushing time was significantly correlated to lactate (R = 0.51; P = 0.0003), pH (R = -0.38; P = 0.009) and base deficit (R = 0.33; P = 0.026), but not to T/QRS ratio (R = 0.002; P = 0.99). No significant correlation between lactate and T/QRS ratios (R = 0.06; P = 0.70) or type of CTG pattern was found (P = 0.10), though there were significant differences in pH (P = 0.029) and T/QRS ratios (P = 0.037) between groups with different FHR abnormalities. CONCLUSION: Lactate increases progressively with maternal pushing time. No significant correlation was found between lactate and the T/QRS ratio. Lack of correlation is likely to be due to poor sensitivity of foetal ECG at this level of foetal stress, though the influence from transplacentally transferred maternal lactate cannot be excluded.
Anaemia in pregnancy--a cross-sectional study in Singapore.
OBJECTIVE: To determine the prevalence and predictors of anaemia in pregnancy in Singapore. DESIGN: Hospital based case controlled study. SETTING: National University Hospital, between January-December 1993. SUBJECTS: All women delivered at the National University Hospital, Singapore in 1993 had their haemoglobin estimated. If it was less than 11 gm/dl, blood was taken to establish the cause of anaemia. Data was also collected with regard to their antenatal progress, and factors predisposing to anaemia in pregnancy. Logistic regression, Chi-square test, Fischer's exact test, Mantel-Haenszel test were used to assess the relationships between categorical variables. RESULTS: The prevalence of anaemia at delivery was 15.3%. The most common cause of anaemia in pregnancy was due to iron deficiency (81.3%). The occurrence of anaemia in pregnancy is related to the socio-economic status of the women. Multiparous women of the lower socio-economic class who tend to book late in pregnancy were found to have the highest risk of anaemia. Multivariate logistic regression analysis revealed iron prophylaxis, haemoglobin level at booking, race and previous history of anaemia in earlier pregnancy as important predictors of anaemia at delivery. The odds of anaemia for a woman not on therapy was about 11 times that of her counterpart on prophylactic iron therapy (95% CI 8.76-14.13). A 55% reduction in odds of anaemia was estimated per 1 gm% increase in haemoglobin level at booking. As compared to Chinese, Malays and Indians who experienced significant increase in odds of anaemia of 95% and 58% respectively. Further, a pregnant woman with a previous history of anaemia is 2.6 times as likely to be anaemic, as compared with one without history of anaemia. Except for a higher incidence of preterm delivery, there was no other statistically increased risk of complications in the antepartum, intrapartum or postpartum periods. There was no difference in the incidence of antepartum haemorrhage/operative deliveries, postpartum haemorrhage, low birthweight, intrauterine growth retardation and neonatal outcome. CONCLUSIONS: The study confirms that iron deficiency anaemia is the most common cause of anaemia in pregnancy and is a major health problem in developing and developed countries.
Cytochrome P-450 cholesterol side-chain cleavage expression in human spermatozoa.
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Prophylactic oophorectomy: a continuing controversy.
Prophylactic oophorectomy remains a controversial issue among gynecological surgeons. A woman's history of hereditary ovarian cancer syndrome is currently considered the most important indication for prophylactic oophorectomy. This is because of the high risk of ovarian cancer developing in these women and the poor prognosis that is generally associated with ovarian cancer. The purpose of prophylactic oophorectomy in women with no family history of hereditary ovarian cancer syndrome who present for hysterectomy because of other gynecological indications is, however, less clear. The attitude of the patients toward removal of normal ovaries deserves special consideration when counseling for prophylactic oophorectomy in this group of women. Knowledge about the risk of ovarian cancer in the conserved ovaries, cancer phobia, possible psychological effects of prophylactic oophorectomy, and the need for long-term hormone replacement therapy if prophylactic oophorectomy is carried out, are all important considerations in the counseling process.
Intrapartum fetal hypoxia and biochemical markers: a review.
Intrapartum fetal hypoxia is a rare event, although fetal intrapartum surveillance is discussed as a subject of major importance. This is mainly because of consequences of fetal hypoxia that may lead to cerebral palsy. A fetus suffering from hypoxia initially compensates by producing energy through anaerobic metabolism. At some stage, the fetus becomes decompensated and basic cellular functions fail, with risks of permanent morbidity or mortality. How long a fetus can survive on anaerobic metabolism differs because metabolic reserves differ, i.e., growth-restricted fetuses might deteriorate at an earlier stage. An increasing body of evidence has clarified brain-damaging mechanisms. Neuronal loss occurs in two phases: during the primary hypoxic event and later during the reperfusion/reoxygenation phase. Animal studies have suggested the possibility of prophylactic treatment to prevent neuronal loss after the hypoxic event. Intrapartum diagnostic tools should aim for detecting fetal hypoxemia/hypoxia when the fetus is still compensated. This may be achieved by assessment of biochemical data such as pH, lactate, and oxygen saturation, with the aim of prophylactic intervention before the fetus becomes decompensated. The measurement of cord blood levels of oxygen free radicals and excitatory amino acids at the time of birth may prove to be helpful in determining the risk of brain damage and evaluating the effect of prophylactic treatments to prevent or ameliorate brain injury from hypoxia.
Preeclampsia: haemostatic status and the short-term effects of methyldopa and isradipine therapy.
OBJECTIVE: To determine the haemostatic status in preeclampsia and to investigate the effects of short-term use of anti-hypertensive drugs, methyldopa and isradipine. METHODS: Thirty preeclamptic (PE) women admitted to the hospital for observation and treatment were randomized to receive either methyldopa or isradipine for 2 weeks. Their blood pressure were monitored for 24 h before treatment and again at 7 days and 14 days after treatment using the programmable automated ambulatory blood pressure (ABP) monitoring system. Blood sampling was performed before commencement of anti-hypertensive treatment, 7 days and 14 days after treatment and the haemostatic parameters studied was compared before treatment with normal pregnancy and the effect of anti-hypertensive treatment. Nineteen normal pregnant subjects with a total of 30 blood sampling at various gestation and good pregnancy outcome served as controls. The following haemostatic parameters were determined; thrombelastography, fibrinogen, antithrombin III (ATIII), thrombin-antithrombin (TAT)-complex, beta-thromboglobulin (beta-TG), plasminogen activators (t-PA, u-PA), plasminogen activator inhibitors (PAI-1, PAI-2), and plasminogen. RESULTS: Significant lowering of blood pressure was evident at Days 7 and 14 of therapy with either methyldopa or isradipine. Increased mean plasma fibrinogen and decreased ATIII levels were seen in preeclampsia together with decreased u-PA and t-PA activity levels in contrast to increased t-PA antigen and beta-TG. No significant differences were seen for TAT-complex, PAI-1, plasminogen and D-dimer levels although their mean levels were higher than observed in non-pregnant subject except for PAI-2, the level was significantly reduced when compared with normal pregnancy. Two-way analysis of variance showed no significant alteration on all haemostatic parameters studied in preeclamptic women receiving either methyldopa or isradipine after 7 and 14 days of therapy. CONCLUSION: Enhance activation of coagulation was observed together with raised fibrinolysis in normal pregnancy and PE. However, in PE a further reduction in ATIII, u-PA and PAI-2 with increased fibrinogen and platelet activation could lead to an imbalance in the coagulation/fibrinolysis equilibrium which favours fibrin deposition. All these changes seen in PE including the coagulation kinetics were not altered by the short term effects of methyldopa and isradipine even though significantly lowered blood pressure were observed during therapy.
The reliability of catheter-tip transducers for the measurement of intrauterine pressure in the third stage of labour.
In order to assess the reliability of intrauterine pressure measurements in the third stage of labour, catheter-tip transducers were used in 20 women randomly allocated into two groups of 10. In each case in the first group two catheters were tied together and introduced transcervically into the uterine cavity after delivery of the placenta. In each case in the second group two catheters were inserted independently into the same uterine cavity. The active and cumulative active pressures recorded from the pairs of catheters within each uterine cavity were compared. Comparison of individual active pressure readings from separate transducers revealed good agreement whether the catheters were tied together or were separate. Cumulative active pressure was very similar when assessed by each catheter in the same uterus. Intrauterine catheter-tip transducers can be used reliably to measure uterine activity in the third stage of labour although there may be minor contraction by contraction differences in recordings of individual active pressures.
Evaluation of a new portable system for cord lactate determination.
To evaluate a new reflectance photometer (Accusport) for blood lactate determination, a prospective non-interventional study was performed on blood obtained from the umbilical cord artery immediately after delivery of the baby in 109 consecutive women. For each sample, the results of cord arterial blood lactate values measured with the reflectance photometer were compared with those obtained using a reference method in the laboratory. The values obtained using Accusport were comparable in accuracy with those obtained using a laboratory reference method (Ektachem 9501RC). The instrument provides a simple and reliable method for determining cord arterial blood lactate levels in a small blood sample.
Validation of a laboratory method of measuring postpartum blood loss.
Laboratory methods give more accurate measurement of blood loss in the postpartum period than visual estimation. In order to evaluate a laboratory method used to quantify blood loss postpartum, blood lost at gynecological operations was collected in a measuring bottle. The measured amount of blood (50-1,000 ml) was then poured onto absorbent paper towels and sanitary pads, in order to mimic conditions when measuring blood loss in clinical trials in the postpartum period. The amount of blood absorbed onto the absorbent paper and sanitary pads was measured by a rapid method of automatic extraction and photometric measurement of alkaline hematin. The study shows that the method provides a reliable and accurate means of measuring blood loss. The error in each case was less than 10% with an intraclass correlation coefficient of almost 1.
Correlation of change in uterine activity to blood loss in the third stage of labour.
In 47 women, the change in the uterine activity after the administration of a uterotonic agent was correlated with the amount of blood loss during the same period of time. Uterine activity was measured by a Gaeltec catheter-tipped pressure transducer inserted transcervically within 5 min of delivery of the placenta. A uterotonic agent (either intravenous syntocinon, intramuscular syntometrine or oral misoprostol) was given after the insertion of the intrauterine pressure catheter and pressure recorded for another 90 min. Blood loss over the same 2-hour period was collected with absorbent paper which was then assessed by colorimetric measurement of the haemoglobin content in the sample. Our results show that the change in uterine activity is associated with the total blood loss. However, there is a poor linear correlation between the two variables probably because of the biological variation in myometrial activity and differences in coagulation mechanisms in normal women.