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Biomedical subjects

O A Viegas

Publications and source records attributed to O A Viegas.

At least 37 records · Page 2Linked to original sources
PubMed1993

Evaluation of hemostatic function following Norplant implant removal.

Norplant implant use in Singapore showed a decrease in vitamin K-dependent Factors II, V, VII and reduction in fibrinolytic activity at the end of 5 years of use. Increased platelet numbers and accelerated platelet aggregation were also found throughout the 5 years of Norplant use. It thus appears that unlike the combined pill, prolonged Norplant use does not activate the coagulation system and does not enhance a state of hypercoagulation. On removal of the Norplant implants at the end of 5 years, the significant changes seen in hemostatic function observed with Norplant use remained.

Blood Coagulation↗
PubMed1993

Tramadol in labour pain in primiparous patients. A prospective comparative clinical trial.

The analgesic efficacy and safety of tramadol 50 mg, 100 mg and pethidine 75 mg, administered intramuscularly were compared in a randomized, double-blind clinical trial in 90 pregnant women with labour pain. Pain relief was measured by a 4-point verbal rating scale 10, 20, 30, 45 and 60 min after the administration of study drugs. The average total pain relief score within the first hour was 0.9 with tramadol 50 mg, 1.7 with tramadol 100 mg and 1.7 with pethidine 75 mg. In comparison to both tramadol doses the administration of pethidine was associated with a significantly higher frequency of adverse events and a significantly lower respiratory rate in the neonates. The results indicate that tramadol 100 mg is as effective as pethidine 75 mg but has a superior safety profile.

Adolescent↗
PubMed1993

Premature childbirth: social and behavioural risks in Singapore.

The associations of social and behavioural factors on preterm birth in Singapore were studied using hospital maternity records of 20,723 consecutive singleton births between January 1986 and November 1991. The overall proportion of preterm births was 3.6%, the rates for the Chinese, Malay and Indian groups being 3.2%, 3.8% and 4.9% respectively. Teenage mothers were at a higher risk of preterm labour compared to women aged 20-29 years. The incidence of preterm labour decreased with increasing educational status. Preterm births were six times more likely in women who had no antenatal care. Women who had three or more previous births were at a higher risk, while those who had one or two previous births were at a lower risk compared to women who had none.

Adult↗
PubMed1993

Lipid profiles in healthy fertile Singaporean women.

Serum lipid profiles were studied in 167 healthy fertile Singaporean women, aged between 18 and 40 and comprising 114 Chinese, 28 Malays and 25 Indians. Parity or ethnic differences did not affect lipid concentrations. Except for triglycerides which showed a decreasing trend, there was no significant variation in lipid concentrations with age. However, all lipid concentrations except HDL cholesterol (which decreased) appeared to increase with body mass index. Compared with other populations, these Singaporean women appeared to have higher mean concentrations of total cholesterol and lower mean concentrations of HDL cholesterol. The possibility that these differences could have contributed to the increasing incidence of coronary heart disease in Singapore is discussed.

Adult↗
PubMed1993

Decreased levels of amniotic fluid oxytocinase activity in preeclampsia.

Oxytocinase (EC 3.4.11.3) activity was determined in 80 amniotic fluid samples obtained from 40 normotensive primigravidas (median age 27 years) and 40 primigravidas (median age 29 years) with pregnancies complicated by preeclampsia between 32 and 39 weeks of gestation. The enzyme activity was significantly lower in preeclampsia than in normal pregnancy with matched gestations (p < 0.01). Considering the possible involvement of vasopressin and angiotensin II in preeclampsia, it is suggested that the enzyme which degrades these pressor hormones may play a role in the pathogenesis of hypertensive pregnancy.

Adult↗
PubMed1992

Effect of Norplant implants on liver, lipid and carbohydrate metabolism.

In this study involving 100 women, the metabolic changes seen with Norplant use were evaluated. Besides a significant increase in serum bilirubin, there were no other changes in liver function to suggest possible hepatocellular dysfunction at the end of five years. Even the raised mean levels of bilirubin remained within the normal clinical range for the local population. As regards lipid metabolism, total triglycerides, cholesterol and LDL-cholesterol were decreased through the five years of Norplant use. The HDL-cholesterol showed a significant increase in the first year; it then decreased over the years to its preinsertion level at the end of five years. As a result, the HDL-cholesterol/Total cholesterol - HDL-cholesterol showed a significant increase in the first year and then decreased to almost its preinsertion value at the end of five years. The findings appear to indicate Norplant use not to be contributory to cardiovascular risk. The use of Norplant was not associated with any significant effect on carbohydrate metabolism.

Bilirubin↗
PubMed1992

Effect of long-term use of Norplant implants on haemostatic function.

This study describes the effects of Norplant on haemostatic function after 5 years of use in 97 women. There was a decrease in vitamin-K dependent Factors II, V, VII and reduction in fibrinolytic activity at 2 and 4 years of use. Increased platelet numbers and accelerated platelet aggregation were found throughout the 5 years of Norplant use, whilst raised alpha 2-Macroglobulin (a2-M) and antithrombin III (ATIII) antigen level were observed for up to 4 years of use. Prolonged Norplant use does not appear to activate the coagulation system and does not enhance a state of hypercoagulation.

Antigens↗
PubMed1992

Effect of Norplant-2 rods on haemostatic function.

A longitudinal study on one-hundred Singaporean women using Norplant-2 rod implant for contraception and their effects on the haemostatic function was carried out. There was a decrease in vitamin K-dependent Factors II, VII and a tendency towards lowered fibrinolytic activity after prolong use of Norplant-2 rods. The results indicate that the Norplant-2 rod implant system does not contribute towards hypercoagulable state but increased platelets and accelerated platelet aggregation observed will require further study to ascertain whether there is a concomitant increase in platelet activation.

Blood Coagulation Factors↗
PubMed1992

Acceptability of Norplant implants for fertility regulation in Singapore.

The continuation rate at the end of this five-year clinical study was 60% with no accidental pregnancy occurring throughout the five years. The post-removal conception rate in women desiring pregnancy was 92% at the end of two years. The majority of acceptors described the overall experience with the implants as favourable. In fact, 75% of the women planning to use contraception after removal of the implants were going to use implants again.

Adult↗
PubMed1992

Acceptability of Norplant-2 rods as a method of family planning.

The Norplant-2 rod system consists of two silastic rods in which levonogestrel has been incorporated with the polymer. The continuation rate at the end of five year was 62%. No accidental pregnancies occurred throughout the five years of use. The post-removal conception rate in women desiring pregnancy was 70.8% at the end of two years. The majority of acceptors were happy with the rods and 86.8% expressed the desire to have another set of implants inserted following removal of the first set. The study shows the Norplant-2 rod system to be a well accepted method of family planning.

Adult↗
PubMed1992

Effect of Norplant-2 rods on liver, lipid and carbohydrate metabolism.

The effect of Norplant-2 rods on liver, lipid and carbohydrate metabolism was evaluated in 100 women using Norplant-2 rods. Besides a significant increase in serum bilirubin, there was no other obvious evidence to suggest any possible hepatocellular dysfunction with the use of Norplant-2 rods. As regards lipid metabolism, decreases in total triglycerides, cholesterol and LDL-cholesterol and HDL-cholesterol were initially seen. These parameters returned to their preinsertion mean at the end of five years. As a result, the value of the HDL-cholesterol/total cholesterol - HDL-cholesterol and LDL-cholesterol/HDL-cholesterol ratios remained around their preinsertion value at the end of five years. All this appears to indicate that the use of Norplant-2 rods is not directly contributory to cardiovascular risk. The use of Norplant-2 rods was not associated with any significant effect on carbohydrate metabolism.

Asia, Southeastern↗
PubMed1992

Plasminogen activators and inhibitors in normal late pregnancy, postpartum and in the postnatal period.

Tissue plasminogen activator (t-PA), urokinase plasminogen activator (u-PA) and plasminogen activator inhibitors (PAI) are elevated in late pregnancy with t-PA and u-PA remaining so at 6 weeks postnatal. PAI-2 remains at postpartum but was absent by 6 weeks postnatal unlike PAI activity which was absent at postpartum and returned to nonpregnant level at postnatal. The potential fibrinolytic response to stress is much reduced in pregnancy thus increasing the risk of thromboembolism.

Adult↗
PubMed1992

Pregnancy in patients with systemic lupus erythematosus.

The view that SLE in pregnancy is associated with poor maternal and perinatal outcome is generally accepted. Consequently, there is a mistaken but commonly held belief that termination of such pregnancies will safeguard maternal health. However, because of advances in diagnostic technology, improved antenatal and neonatal surveillance, wider treatment options and a clearer understanding of the pathological processes involved, such a view is no longer tenable. This article outlines the changes in obstetric practice that have made pregnancy in women with SLE a relatively safe process. In particular, it emphasizes the need for a multidisciplinary approach to caring for such pregnancies. It also draws out some of the experiences we have had with the management of such pregnancies in Singapore that will reinforce the view that women with SLE can reproduce safely and successfully given appropriate care.

Birth Weight↗
PubMed1992

Safe childbirth needs more than medical services.

This article reviews nonmedical factors contributing to maternal mortality in Indonesia, the Philippines, and Thailand. In general, countries or regions should define their own priorities for intervention strategies designed to diminish the influence of such factors.

Adolescent↗
PubMed1991

Plasminogen activators t-PA, u-PA and its inhibitor (PAI) in normal males and females.

We determined the plasma levels of tissue plasminogen activator (t-PA), plasminogen activator inhibitor (PAI) activity and their antigen levels including urokinase plasminogen activator (u-PA) in 33 male and 27 female normal subjects. Males had mean t-PA activity of 0.50 iu/ml which was significantly lower (p less than 0.01) than the females 0.64 iu/ml. Males had higher (p less than 0.001) mean PAI activity (15.5 AU/ml) as compared to females 10.3 AU/ml. The respective mean levels of t-PA and PAI antigen were significantly higher (p less than 0.01) in males (8.1 ng/ml and 17.6 ng/ml) than in females (6.2 ng/ml and 12.1 ng/ml). The mean u-PA level in males was 1.54 ng/ml which was significantly higher (p less than 0.01) than in females with 1.02 ng/ml. In post-venous occlusion studies, females had a greater mean response of 8.6 fold in t-PA activity as compared to males with a mean of 4.5 fold increase. The mean t-PA antigen response in males was 2.0 fold increase as compared to 2.6 fold increase in the females. No significant responses were seen in both sexes in either PAI activity or antigen levels when compared with the resting state. In zymography studies, free t-PA, its inhibitor complexes and u-PA were demonstrated in the euglobulin fractions of stored plasma. This study demonstrates that significant differences in t-PA, u-PA and PAI exist between male and female subjects which should be taken into account when determining their levels in clinical conditions.

Adult↗
PubMed1991

Lipid profiles during and after normal pregnancy.

Lipid profiles were estimated in two groups of normal healthy women comprising 39 non-pregnant women and 67 pregnant women at 28 and 32 weeks gestation and 6 weeks after delivery. Triglycerides, total, HDL and LDL cholesterols were high during pregnancy. Except for LDL cholesterols which remained constant, all the above decreased at 6/52 postnatally, but levels were still above those of normal non-pregnant women. Compared to the later, the atherogenic index, LDL/HDL cholesterol ratio was unchanged during pregnancy but significantly increased at 6/52 postnatally. These results may suggest that while total lipid levels increase during pregnancy, this is balanced by an even distribution of the lipoprotein fractions. After delivery, though lipid levels had decreased, the decrease in HDL cholesterol and increase in LDL cholesterol caused unfavourable changes in lipid-lipoprotein ratios. These changes may be due to the change in metabolism of the pregnant women as well as diet during and after pregnancy.

Adult↗