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Biomedical subjects

Y Tannirandorn

Publications and source records attributed to Y Tannirandorn.

At least 19 recordsLinked to original sources
PubMed1992

Intra-amniotic pressures following vaginal gemeprost prior to first and second trimester termination of pregnancy.

Intra-amniotic pressures were measured following 1 mg gemeprost for cervical preparation before first trimester vacuum aspiration (n = 10) and following 2 mg gemeprost before second trimester dilatation and evacuation (n = 15). Twenty-five women, matched for gestational age and parity, who did not receive gemeprost served as controls. Compared to control values (2-8 mmHg), basal intra-amniotic pressure (IAP) was significantly increased after 1 mg and 2 mg of gemeprost (median 20.0, range 4-45 mmHg, median 20.0, range 8-60 mmHg, respectively). Uterine contractions were recorded in 8 of 10 subjects after 1 mg (median delta IAP 28.0, 95% CI 10.0-42.6 mmHg) and 14 of 15 subjects after 2 mg (median delta IAP 52.5, 95% CI 26.7-60.3 mmHg). Gemeprost produces an increase in uterine contractility which may be additional to cervical softening properties and which may be responsible for the adverse effects of pain and bleeding experienced by some women prior to termination.

Abortion, Induced↗
PubMed1992

Midpregnancy plasma zinc in normal and growth retarded fetuses--a preliminary study.

OBJECTIVE: To determine plasma zinc concentrations in normally and abnormally growing fetuses. DESIGN: Prospective observational study. SETTING: Fetal Medicine Unit, Queen Charlotte's Maternity Hospital. SUBJECTS: 53 pregnant women attending for fetal blood sampling at between 18 and 40 weeks gestation. 27 fetuses were normal (central group), 11 fetuses were growth retarded and 15 were malformed. MAIN OUTCOME MEASURES: Plasma zinc concentrations in maternal and fetal blood at time of fetal blood sampling. RESULTS: In normally growing fetuses, between 18 and 40 weeks gestation, there was no fall in maternal plasma zinc concentration; the fetal level fell by 36%. In 10 fetuses with symmetrical growth retardation, plasma zinc concentration tended to be low, but was not significantly different from that in the normal control fetuses. CONCLUSION: The results suggest that (i) placental transfer of zinc is an uphill secretory process and that it is a rate-limiting step in the accumulation of zinc by the fetus and (ii) in fetuses with symmetrical intrauterine growth retardation, a low plasma zinc is probably a parallel phenomenon and not necessarily an aetiological factor.

Female↗
PubMed1992

Normal amniotic pressure throughout gestation.

OBJECTIVE: To characterize amniotic pressure (AP) in pregnancies with normal amniotic fluid volume. DESIGN: Observational study, mainly cross-sectional. SETTING: Fetal medicine unit within a tertiary referral hospital. SUBJECTS: Patients undergoing transamniotic invasive procedures in whom amniotic fluid volume was subjectively assessed as normal on ultrasound. Those beyond 16 weeks with a deepest vertical pool on ultrasound less than 3.0 or greater than 8.0 cm were excluded. Overall 194 pregnancies were studied on 232 occasions between 7 and 38 weeks gestation. INTERVENTIONS: Manometry readings referenced to the top of the maternal abdomen were obtained via a fluid-filled line from the needle hub and either connected to a pressure transducer (n = 190) or held vertically against a ruler (n = 42). MAIN OUTCOME MEASURES: AP in mm Hg, AP corrected for gestational age (z scores), semi-quantitative ultrasonic indices of amniotic fluid volume, clinical variables. RESULTS: AP in singleton pregnancies increased with advancing gestation (P less than 0.001), and the sigmoid-shaped regression curve plateaued in the mid-trimester. AP z scores were not influenced by volume-related phenomena such as twin gestation, the deepest vertical pool, or amniotic fluid index, nor by maternal age, parity, gravidity, fetal sex, or subsequent spontaneous preterm delivery. CONCLUSIONS: These findings suggest that AP is not principally determined by intrauterine volume. We speculate that AP, which reflects change in uterine tension as a function of radius, may instead be determined by gestation-specific anatomical and hormonal influences on gravid uterine musculature. A reference range for AP has been constructed for use in amnioinfusion and amnioreduction procedures.

Amniotic Fluid↗
PubMed1992

Biparietal diameter/femur length ratio and actual femur length/expected femur length ratio: a sonographic screening method for Down's syndrome.

Several ultrasonographic signs have been described in second-trimester Down's syndrome fetuses. Previously published reports have shown that fetuses affected with Down's syndrome have normal biparietal diameter (BPD), high BPD-to-femur length (FL) ratio, and low actual FL-to-expected FL ratio. A retrospective comparison of the BPD-to-FL ratio and actual FL-to-expected FL ratio was made between 3 fetuses with Down's syndrome diagnosed prenatally by second-trimester amniocentesis and 189 normal fetuses with gestational age varying from 13-25 weeks who were seen in the Ultrasound Unit of Department of Obstetrics & Gynaecology, Chulalongkorn Hospital between January 1, 1989 and May 31, 1990. The sensitivity of BPD-to-FL ratio and actual FL-to-expected FL ratio as a screening technique for Down's syndrome in this study was 66.7 and 100 per cent, with a specificity of 93.4 and 89.2 per cent respectively. These sonographic parameters appear to be a useful screening method for Down's syndrome.

Down Syndrome↗
PubMed1991

Further predictors of renal dysplasia in fetal obstructive uropathy: bladder pressure and biochemistry of 'fresh' urine.

Urine was aspirated on two consecutive days from the dilated bladder of nine fetuses with lower urinary tract obstruction. Gestational age ranged from 17 to 35 weeks. Renal dysplasia was diagnosed histologically in four fetuses, whereas the other five had normal renal histology or only partial dysplasia. Urinary sodium (Na+) and osmolality (Osm) decreased significantly in the second urine sample 1 day after bladder emptying (median decrease: Na+ = -11.3 per cent; Osm = -13.3 per cent). Although there were no significant differences between fetuses with or without renal dysplasia, normalization of an initially raised urine Na+ concentration occurred at the second sample in a fetus with partially normal renal histology, thus correcting a false-positive diagnosis of dysplasia. Bladder pressure was measured at the time of the first urine sampling in seven fetuses and in a further eight with bladder outlet obstruction undergoing a single urine aspiration at 18-28 weeks. Bladder pressure was increased above the reference range in 8 of 15 fetuses with urinary obstruction, but there was no correlation between pressure and the degree of impairment of renal function. Although no conclusive clinical guidelines can be drawn from this study for the evaluation of fetal renal function, these findings suggest that, in lower urinary tract obstruction, tubular reabsorption is impeded by the standing pressure in the urinary tract and that improvement of renal function may occur following relief of obstruction.

Electrolytes↗
PubMed1991

Management of immune haemolytic disease in the fetus.

Although Rh alloimmunization has been successfully reduced in frequency and severity since the implementation of Rh immune globulin, cases still occur. The management of affected pregnancies requires the efforts of a team which includes obstetrics/fetal medicine, the blood transfusion service, haematological support, nursing assistance and neonatology. The aim of antenatal management is to predict whether or not the fetus is severely affected, to correct the fetal anaemia and to deliver the baby at the optimal time. The management has improved markedly with the introduction of high-resolution real-time ultrasound, fetal blood sampling, intravascular fetal blood transfusion and/or intraperitoneal transfusion and meticulous fetal surveillance. With appropriate and timely management in severely alloimmunized patient, the survival rate of affected fetuses in some centres is now about 90%. There is still a need for research into new methods of treatment such as high dose intravenous immunoglobulin, which might non-invasively diminish fetal red cell destruction. Due to the reduced frequency of severe disease, regionalized treatment centres are essential in order to maximize the experience and efficiency of the management teams.

Blood Group Antigens↗
PubMed1991

Production of urinary 11-keto-thromboxane B2 in normal and hypertensive pregnancies.

Urinary levels of 11-keto-thromboxane B2 (11-keto-TXB2), were elevated at all gestational ages (12-41 weeks) compared with non-pregnant levels. 11-keto-TXB2 levels exceeded those of TXB2 throughout pregnancy, which suggested that 11-keto-TXB2 may be the major urinary metabolite of TXA2 in normotensive pregnancy, as in the non-pregnant state. This was reversed in women with mild pregnancy-induced hypertension (P.I.H.), such that urinary levels of TXB2 were higher (p less than 0.01) than those of 11-keto-TXB2. Since the 11-thromboxane dehydrogenase enzyme is found in the placenta, the low levels of 11-keto-TXB2 may be the result of placental damage decreasing the activity of the enzyme. The relationship between these findings and the aetiology of P.I.H. is not clear, but changes in urinary 11-keto-TXB2 may be of use in identifying those women at risk of developing P.I.H.

Adult↗
PubMed1991

Changes in concentrations of cortisol, dehydroepiandrosterone sulphate and progesterone in fetal and maternal serum during pregnancy.

OBJECTIVE: In fetuses, adrenal steroids have been implicated in organ maturation and in some species in initiation of labour. The fetal adrenal gland differs from the adult in its complement of steroid metabolizing enzymes. This study sought to examine the changes in peripheral cortisol, progesterone and dehydroepiandrosterone sulphate (DHEAS) in unstressed fetuses during pregnancy. DESIGN: Paired maternal and fetal samples were collected from 47 patients. Fetal blood samples were collected by transabdominal needling. All fetuses were appropriately grown for age which ranged from 18 to 41 weeks. MEASUREMENTS: Hormones were measured using specific, validated immunoassays. RESULTS: Fetal progesterone (mean, 822 nmol/l; 95% data intervals 196-1449 nmol/l) varied considerably between individuals but there was no significant change in serum concentration with gestational age, nor was there any difference between male and female fetuses. There was a small, but significant (y = 0.339x2 - 13.5x + 231; r = 0.72, P = 0.0001) rise in cortisol in the fetal circulation from 32 to 41 weeks gestational age, whereas the mean fetal DHEAS concentration decreased linearly with gestational age from 4.1 mumol/l at 18 weeks to 2.6 mumol/l at 41 weeks (r = -0.41; P = 0.007). Mean progesterone concentration in the maternal serum increased linearly from 98 nmol/l at 18 weeks to 783 nmol/l at 41 weeks. In the fetus there was a significant correlation between progesterone and cortisol concentrations. CONCLUSIONS: These results are compatible with the proposed role of cortisol in fetal lung maturation, confirm high levels of progesterone in the fetus from an early stage of gestation, and provide further evidence for placental progesterone being the precursor of fetal cortisol.

Adrenal Cortex Hormones↗
PubMed1991

Fetal liver dysfunction in Rh alloimmunization.

The liver enzymes, aspartate transaminase (AST), alanine transaminase (ALT), gamma glutamyl transpeptidase (GGT) and alkaline phosphatase (ALP), were measured in the blood of 25 fetuses with severe Rh alloimmunization at the time of their first, second and third intravascular transfusions and in 17 comparison fetuses. In the comparison group, GGT increased with advancing gestation (r = 0.7; P = 0.002), whereas ALP, AST and ALT did not correlate with gestational age. Rh hydropic fetuses (n = 8) had higher blood ALT levels than the comparison fetuses (P = 0.008) had significantly increased transaminases when compared with non hydropic fetuses (n = 17). In hydropic fetuses, AST correlated with the nucleated red cell count before transfusion (r = 0.94; P = less than 0.0001). Fetal transaminases were no longer increased in hydropic fetuses by the second (AST) or third (ALT) transfusion. In both hydropic and non hydropic fetuses, GGT increased by the second transfusion (median percentage change +85%, range -83% to +596%; P = 0.003). The rise in fetal GGT was transitory and correlated with the increase in fetal haematocrit at the first transfusion (r = 0.58; P = 0.006). This study reports liver dysfunction secondary to extramedullary erythropoiesis in Rh alloimmunization and implicates portal hypertension for the rise in fetal GGT with transfusion.

Alanine Transaminase↗
PubMed1991

Direct antenatal fetal electrocardiographic waveform analysis.

OBJECTIVE: To establish a technique for continuous recording of fetal electrocardiograms (ECG) for waveform analysis in the antenatal period. DESIGN: Prospective descriptive study. SETTING: Fetal Medicine Unit, Queen Charlotte's and Chelsea Hospital, London, UK. SUBJECTS: 35 women undergoing antenatal fetal blood sampling. INTERVENTIONS: One end of an insulated Cooner wire was attached to the sampling needle and the other to an automatic ECG-ST waveform analyser. MAIN OUTCOME MEASURES: ECG signals were obtained with the needle in the fetal abdomen during intrahepatic umbilical vein sampling or aspiration of fetal urine but not when it was in the placental cord insertion. RESULTS: Continuous recording of the T/QRS ratio was obtained for a total of 166 min (mean 8 min per fetus) from 20 fetuses (16-38 weeks). The T/QRS ratio had no correlation with gestational age and fetal heart rate and was similar to values described in term fetuses in labour. CONCLUSIONS: The technique described can identify ST waveform changes and may be useful in the investigation of fetal cardiac arrhythmias, intrauterine growth retardation and in monitoring fetal transfusions.

Electrocardiography↗
PubMed1991

Fetal blood sampling from the intrahepatic vein for rapid karyotyping in the second and third trimesters.

One hundred and twelve fetuses with structural anomalies (n = 84), intrauterine growth retardation (n = 21) or amniotic fluid volume disorders (n = 7) detected by ultrasound underwent blood sampling from the intrahepatic vein for rapid karyotyping. The procedure was successful in 95.5%. 12.5% of the fetuses had an abnormal karyotype. Fetal bradycardia was observed in two fetuses (1.8%) and intraperitoneal bleeding in three (2.7%). There were three procedure-related losses but these were not due to the intrahepatic vein sampling itself. Fetal blood sampling is the method of choice for rapid karyotyping in the second and third trimesters, and the intrahepatic vein is an alternate site when access is difficult or failure to sample occurs at the placental cord insertion. Additional advantages of fetal blood sampling at the intrahepatic vein include absence of cord complications, reduced risk of fetal blood loss and fetomaternal haemorrhage, and the lack of need to confirm the fetal origin of the sample.

Blood Specimen Collection↗
PubMed1991

Maternal perception of sound-provoked fetal movement as a test of antepartum fetal wellbeing.

Maternal perception of sound-provoked fetal movement test was studied on 506 occasions in 443 women with obstetric or medical antenatal risk factors after 26 weeks gestation. The response was compared with a nonstress test (NST) performed immediately after a three-second vibroacoustic stimulation with an electronic artificial larynx. A positive response to sound stimulation, recorded as a fetal movement by the mother, occurred on 497 occasions (97.3%) and was accompanied by a reactive NST on 484 occasions; giving a specificity of 99.6 per cent and a negative predictive value of 97.4 per cent. An inconclusive or negative response to sound (2.7%) had a sensitivity of 35.0 per cent and a positive predictive value for a nonreactive NST of 77.8 per cent. Results of sound-provoked fetal movement test and NST, performed within a week of delivery, in 434 women were compared with fetal outcome. The maternal perception of sound-provoked fetal movement test had better specificity (99.1% vs 96.9%), positive predictive value (55.6% vs 35.0%) for poor fetal outcome than the NST, although its sensitivity (50.0% vs 70.0%) and negative predictive value (98.8% vs 99.3%) were lower. Maternal perception of sound-provoked fetal movement test may suffice as an inexpensive and simple method of evaluating antepartum fetal well-being in risk situations. When the mother does not feel any sound provoked fetal movement, NST is then performed. This clinical application can be helpful in a primary health care setting where rapid assessment of fetal health at risk is required.

Acoustic Stimulation↗
PubMed1991

Rapid karyotyping in the second and third trimesters for fetuses at risk of chromosomal abnormalities at Chulalongkorn Hospital.

Transabdominal fetal blood sampling under ultrasonic guidance was performed in 20 fetuses at 18 to 34 weeks gestation. Pure fetal blood was obtained in all cases; 11 from the umbilical veins at the placental cord insertion, 7 from the fetal intrahepatic veins and 2 from the fetal hearts. Rapid karyotype was obtained within 7 days by fetal lymphocyte culture. Chromosomal abnormality was detected in 5 (25.0%) fetuses. Abnormal karyotype was found in 4 of 8 fetuses with structural malformations detected by antenatal ultrasound and in 1 of 5 fetuses of elderly mothers at advanced gestational ages. This suggested that in fetuses at risk of chromosomal abnormality, rapid karyotype should be obtained and fetal blood sampling is justified in the second or third trimester.

Adolescent↗
PubMed1991

Endocrine pancreatic function in growth-retarded fetuses.

Maternal-fetal glucose gradient and fetal plasma glucose, insulin, and glucagon were measured in 63 fetuses: 34 controls and 29 with growth retardation (nine with and 20 without end-diastolic frequencies in the umbilical artery). Maternal-fetal glucose gradient and fetal glucagon levels were higher in the growth-retarded group than in controls (P less than .001), whereas fetal insulin and glucose concentrations were lower (P less than .001). Although maternal-fetal glucose gradient, fetal glucose, and insulin concentrations were similar among the growth-retarded fetuses, fetuses without end-diastolic frequencies in the umbilical artery had higher fetal glucagon levels (P = .01) than those with end-diastolic frequencies. In growth-retarded fetuses, the increase in fetal glucagon might reflect a compensatory response to hypoglycemia and appears to be a better index of fetal compromise than is glucose or insulin.

Blood Glucose↗
PubMed1990

Fetal cystic hygromata: insights gained from fetal blood sampling.

Twelve second-trimester fetuses with cystic hygroma underwent fetal blood sampling for rapid karyotyping, haematologic evaluation, and blood gas analysis. An abnormal karyotype was found in seven cases: monosomy X in five, trisomy 21 in one, and trisomy 13 in the other. Eight of ten fetuses undergoing blood gas analysis showed hypoxaemia, five of which were growth-retarded. Nine pregnancies were terminated. Of the remaining three, only one fetus survived the perinatal period.

Blood Gas Analysis↗
PubMed1990

Continuing controversy in alloimmune thrombocytopenia: fetal hyperimmunoglobulinemia fails to prevent thrombocytopenia.

Two patients with severe alloimmune thrombocytopenia were managed by weekly intrauterine platelet transfusions at 25 to 36 weeks. In one patient high-dose immunoglobulin was also administered weekly to the mother, and high maternal and fetal immunoglobulin levels were achieved. Fetal platelet counts were similar in both patients. The only variable that affected fetal platelet concentration was the posttransfusion platelet count from the previous transfusion.

Blood Transfusion, Intrauterine↗
PubMed1990

New approaches in the treatment of haemolytic disease of the fetus.

The incidence of Rh haemolytic disease of the fetus and newborn complicating pregnancy has fallen since the implementation of prophylaxis with Rh immune globulin. However, occasional mismatched blood transfusions and ineffective or inadequate prophylaxis still result in a few Rh-alloimmunized patients requiring treatment during pregnancy. The development of a safe technique for obtaining pure fetal blood samples has provided the opportunity to assess correctly the severity of anaemia and to study fetal haematology and biochemical parameters, and hence to gain a better understanding of the pathophysiology of this condition. The aim of antenatal management is to predict whether or not the fetus is severely affected, to correct fetal anaemia and to deliver the baby at the optimal time. Fetal IVT is the standard treatment in severe Rh alloimmunization in many centres. However, high volume transfusion without overloading the fetal circulation, as well as increasing the interval between transfusions without jeopardizing the fetal condition, can be achieved by a combination of IVT and IPT. Thus, the total number of transfusions needed and the overall procedure-related risk for each fetus is reduced. With the recent advances in fetal medicine, haematology and neonatology, the survival rate of affected fetuses in some centres is now about 90%. Fetal death will continue to be associated with two sets of circumstances: trauma or complications due to IVT or IPT in early gestation when delivery is not feasible, and late referrals with such severe hydrops that its reversal is not possible. There is still, therefore, a need for research into new methods of treatment, such as high dose intravenous IgG, which can non-invasively diminish fetal red cell destruction.

Blood Grouping and Crossmatching↗