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Biomedical subjects

N B Patel

Publications and source records attributed to N B Patel.

At least 37 records · Page 2Linked to original sources
PubMed1989

Umbilical artery waveform analysis and biophysical profile. A comparison of two methods to identify compromised fetuses.

Sixty-nine singleton high-risk pregnancies were assessed with both umbilical artery flow velocity waveform analysis and fetal biophysical profile within 10 days of delivery. An abnormal outcome, as defined as either small for gestational age at birth (SGA) or fetal distress during labour, was found in 30 babies. The peak systolic/end diastolic (A/B) ratio from the umbilical artery had a higher sensitivity (37%), specificity (92%), positive predictive value (79%) and negative predictive value (66%) than the fetal biophysical profile (27%, 82%, 53%, and 59%, respectively) in the diagnosis of abnormal outcome. Additional information from a real-time ultrasound assessment, such as the diagnosis of malformations and oligohydramnios could justify a combination of the two methods in antenatal monitoring of high-risk pregnancies.

Blood Flow Velocity↗
PubMed1988

Fetal umbilical artery flow velocity waveforms: prediction of small for gestational age infants and late decelerations in labour.

The relationship between fetal umbilical artery waveform patterns and (a) small for gestational age infants or (b) late fetal heart rate (FHR) decelerations in labour was examined in 205 clinically high-risk pregnancies. All pregnancies were studied using continuous-wave Doppler Ultrasound within 7 days of delivery. Waveforms were analysed by calculating a ratio of peak systolic frequency to end diastolic frequency (A/B ratio). An abnormal Doppler result was defined as being above the 97th centile for gestation from our previously derived normal values. Abnormal Doppler results occurred in only 38% of small for gestational age (SGA) infants and in 70% of those developing late decelerations in labour. Doppler ultrasound is a poor predictor of SGA infants, but may identify a high proportion of cases at risk of developing late FHR decelerations in labour.

Blood Flow Velocity↗
PubMed1988

Effect of a new nonionic contrast agent, ioxilan, on human erythrocytes and the hemostatic and serum complement pathways.

A new nonionic contrast medium (CM), ioxilan, was compared with iohexol and iopamidol. Following incubation of whole heparinized blood with CM, the morphology and osmotic fragility of erythrocytes were studied, the former by transmission electron microscopy. Effects on platelets and hemocoagulation were determined by standard hematologic procedures. Effects on serum complement were evaluated by measurement of total hemolytic complement (CH50), C3, C4 consumption and the presence in serums of C3c as determined by immunoelectrophoresis. Ioxilan affected the erythrocyte membrane less than iohexol and iopamidol: the latter two produced acanthocytes, whereas ioxilan had no effect on erythrocyte morphology; also, erythrocytes exposed to ioxilan (and iopamidol) were more resilient to hypotonic saline solutions than those exposed to iohexol. In all tests, all CM showed anticoagulant activity, albeit much less when compared with ionic CM. At equal iodine concentration, ioxilan reduced the platelet aggregation and whole blood clotting time more than did iohexol. None of the CM activated the serum complement system.

Complement Activation↗
PubMed1988

Mothering problems and child morbidity amongst "mothers with emotional disturbances".

In a study of 1,955 primigravidae who gave birth to a live singleton baby, 227 (11.6%) scored 'positive' (7+) in an antenatal Health Questionnaire enquiring into pre-pregnancy emotional disturbances. This group of mothers had more frequent depression, and this was of longer duration after their delivery compared with those scoring less than 7 (less than or equal to 6). Those scoring 7+ were less likely to breast-feed and the infants were more often ill during the first year of life. There were also differences in 'minor obstetric complications' between the two survey groups. This suggests that the application of this Health Questionnaire antenatally can identify emotionally vulnerable women, who could benefit from support and education during the antenatal period.

Affective Symptoms↗
PubMed1988

Antenatal health questionnaire to identify "mothers with emotional disturbances" as a potential risk group.

An important task in antenatal care is to identify mothers at risk during pregnancy, with the aim of minimizing morbidity and mortality. This paper describes the outcome of a health questionnaire distributed antenatally to 2086 primigravidae during the Tayside Infant Morbidity and Mortality Study 1980-81. The aim of this study was to test a health questionnaire, known to identify mothers with emotional disturbances, and investigate the outcome of their pregnancies. Two hundred and thirty-eight mothers (11.4%) had a 'positive' score in this study. This rather small group of women had a significantly higher incidence of psycho-social risk factors. The questionnaire return rate was high, more than 99%, suggesting that such a questionnaire could be used as a screening instrument to identify 'risk mothers'.

Adult↗
PubMed1987

The effect of fetal heart rate on umbilical artery flow velocity waveforms.

Umbilical artery flow velocity waveforms were obtained using continuous wave Doppler ultrasound in 85 normal pregnancies (25 antepartum, 60 intrapartum) to examine the relation between fetal heart rate, end systolic/end diastolic ratio (A/B ratio) and resistance index (RI). Our results demonstrated a significant negative correlation between fetal heart rate, A/B ratio and RI (in the antepartum group r = -0.49, and in the labouring group r = -0.65). It is therefore important when performing mathematical analysis of umbilical artery flow velocity profiles to make a statistical allowance for fetal heart rate.

Blood Flow Velocity↗
PubMed1987

Mortality and morbidity in infants born between 20 and 28 weeks gestation.

Of 149 infants with ultrasound evidence of gestational age, born in Ninewells Hospital at between 20 and 28 weeks gestation over a 5-year period, 50 were alive at birth. Of these infants, 21 died within 1 week, a further three died within 1 month and a further two within 18 months. Of the 24 survivors, 8 (33%) have significant handicap. The obstetric factors leading to delivery and the mode of delivery are discussed.

Delivery, Obstetric↗
PubMed1987

The predictive value of fetal breathing movements in the diagnosis of preterm labour.

A real time ultrasound investigation was performed on 64 patients who presented in threatened preterm labour. Fetal breathing movements (FBM) were absent in 17 patients, all of whom were delivered within 56 h. FBM were present in 47 patients of whom five were delivered within 56 h from examination and four of these had spontaneous rupture of membranes and/or chorioamnionitis. In 33 the pregnancy continued for at least 1 week. Two of the fetuses with false negative results showed a distinct breathing pattern different from the rest of the study group. This suggests that pattern recognition of fetal breathing might improve the specificity of this investigation.

Female↗
PubMed1985

Response of nerve growth cone to focal electric currents.

Monopolar electric current pulses were focally applied through a micropipette to the growth cone of Xenopus embryonic neurons in culture. Application of the current directly in front of the growth cone modulated the rate of growth cone extension: Negative (sink) currents increased the growth rate, while positive (source) currents reduced the growth rate. When the currents were applied in a direction perpendicular to the direction of the neurite growth, both negative and positive currents produced inhibitory effects. Application of a negative focal current at a 45 degree angle with respect to the direction of neurite growth resulted in an oriented growth of the neurite toward the current sink. However, after the growth cone had been attracted to the vicinity of a current sink, further extension of the neurite was inhibited. These current effects occur rapidly after the onset of the current application, and are at least partially reversible within 1 hr after the termination of the current. The magnitude of current density required to induce a growth cone response was found to be in the order of a few pA per micron2. Such current density is close to that which may be generated at the muscle cell surface by the acetylcholine molecules released from the growth cone during the early phase of nerve-muscle contact.

Animals↗
PubMed1985

An assessment of perinatal mortality in twin pregnancies in Dundee.

An analysis of all perinatal deaths occurring in twin pregnancies in Dundee women from 1956 to 1983 was performed. The uncorrected perinatal mortality rate fell from 116/1000 births in 1956-60 to 16/1000 births in 1981-83, this fall almost entirely taking place after 1975. Causes of death were identified using the Aberdeen Classification and a reduction in deaths in all cause groupings occurred. About half of the deaths were in the Premature, Cause Unknown group and a marked decrease in deaths in this group made the largest contribution to the improved perinatal mortality rate. This fall was partly due to a reduction in the incidence of extreme prematurity and low birth weight. Changes in obstetric management which may have influenced outcome included the introduction of routine early pregnancy ultrasound scanning, the use of tocolytic drugs, intrapartum fetal monitoring, epidural analgesia and an increase in Caesarean section rate from 2% in 1956-60 to 39% in 1981-83.

Delivery, Obstetric↗
PubMed1985

Growth of total intrauterine, intra-amniotic and placental volume in normal singleton pregnancy measured by ultrasound.

The growth of total intrauterine, intra-amniotic and placental volume during the latter half of pregnancy was studied longitudinally with ultrasound in 115 healthy women with normal singleton pregnancies. A parallel planimetric area method was used. The range and distribution of normal values between 20 and 40 weeks was determined for a main study group of 103 primiparous women with which values from 12 parous women were compared. Total intrauterine volume increased from a median of 1006 ml to 4420 ml, intra-amniotic volume from 716 ml to 3406 ml and placental volume, calculated as the difference between total intrauterine and intra-amniotic volume, increased from 259 ml to 801 ml. Variation between individuals was wide at all stages of pregnancy. No significant difference was found between primiparous and parous women. Between successive 5-week periods from 20 to 40 weeks there was evidence that women tended to maintain their initial volume ranking. During the 30-35 week period, rate of growth of total intrauterine and intra-amniotic volume was somewhat faster than the near constant mean rate at other times, while the rate of growth of placental volume decreased after 30 weeks towards term.

Adolescent↗