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Biomedical subjects

N B Patel

Publications and source records attributed to N B Patel.

At least 55 records · Page 3Linked to original sources
PubMed1985

Non-stress antenatal cardiotocography--a prospective blind study.

A prospective blind study of non-stress antenatal cardiotocography was undertaken in a group of 216 'high risk' pregnancies. The 'Cardiff' scores and the outcome of the pregnancies were compared subsequently. Low scores were associated with infants that were small-for-gestational age and fetal distress in labour, while high scores were associated with normal intrauterine growth. Although antepartum cardiotocography is predictive of fetal and neonatal outcome the extent to which its availability will prevent adverse outcome appears limited.

Female↗
PubMed1985

Non-stress antenatal cardiotocography--a prospective randomized clinical trial.

A randomized controlled trial examined the effects of non-stress antepartum cardiotocography on obstetric management and assessed its usefulness as a diagnostic test of fetal compromise. Daily cardiotocograph recordings were made in 396 antenatal patients at increased risk of fetal compromise but were withheld from the clinicians responsible for care in half the cases. The frequency of intrapartum fetal distress and low Apgar score was similar in the two groups. The three normally-formed perinatal deaths all occurred in the revealed group but in only one case could earlier obstetric intervention have altered the outcome. Availability of non-stress cardiotocography was not associated with an increased rate of induction of labour or caesarean section.

Adolescent↗
PubMed1985

Efficacy of intrauterine volume, fetal abdominal area and biparietal diameter measurements with ultrasound in screening for small-for-dates babies.

The efficacy of total intrauterine, intra-amniotic and placental volume measurements with ultrasound in screening for low birthweight (less than or equal to 10th and less than or equal to 3rd centile) was compared prospectively with fetal biparietal diameter and abdominal area measurements at 32 and 36 weeks gestation in an unselected population of 362 women. In all of them the gestation was dated by ultrasound in the first half of pregnancy. Reference values were from a separate normal population studied previously. Total intrauterine volume showed the highest sensitivity in predicting babies weighing less than or equal to 10th centile (58% at 32 weeks and 62% at 36 weeks) and those weighing less than or equal to 3rd centile (78% at 32 weeks and 83% at 36 weeks). A higher number of false-positive tests resulted in a lower predictive value of a positive test (mean 34% for babies weighing less than or equal to 10th centile) than that found for abdominal area (mean 54%). Abdominal measurements selected a smaller 'at risk' group. Biparietal diameter, intra-amniotic and placental volume measurements had inferior predictive capability than total intrauterine volume and abdominal area. For screening purposes abdominal area measurements are presently more suitable than intrauterine volume. The higher sensitivity of intrauterine volume, particularly in early third trimester, is an advantage that requires further investigation with reference to intrauterine growth retardation.

Adult↗
PubMed1985

Intrauterine volume, fetal abdominal area and biparietal diameter measurements with ultrasound in the prediction of small-for-dates babies in a high-risk obstetric population.

The value of fetal biparietal diameter and abdominal area, total intrauterine, intra-amniotic and placental volume measurements for predicting small-for-dates babies in a high-risk obstetric population was investigated in 130 women. A parallel planimetric area method was used to measure volume. The commonest risk factors were suspected intrauterine growth-retardation, hypertensive complications and previous poor obstetric history. The prevalence of birthweight at and below the 10th or 3rd centiles was 30 and 16% respectively. Fetal abdominal area and total intrauterine volume measurements had the highest and comparable sensitivity, specificity and positive predictive value in the detection of infants with birthweights of less than or equal to 10th and less than or equal to 3rd centiles. While these measurements are of use in consolidating the clinical diagnosis of small-for-dates fetuses (growth retardation), high false positive rates (10% and 16-17% for birthweights less than or equal to 10th centile, and less than or equal to 3rd centile respectively) make further discriminatory tests necessary for part of the population.

Adolescent↗
PubMed1985

Pharmacology of new glutarimide compounds.

New glutarimide compounds were synthesized by incorporating piperidine (compounds 1 to 7), diethylamine (8 and 9), morpholine moities (10 to 13), and alkyl derivatives of 3,5 dicyanoglutarimide (14 to 20) at position -1 of the nitrogen atom. Only compounds 1 to 7 at a dose of 8 mg/kg i.p. caused hypermotility, ataxia, tachypnoea and mild tremors in mice. At higher doses (32 mg/kg i.p.), all compounds induced tonic and clonic convulsions, respiratory paralysis and death. The LD50 values of compounds 1 to 20 in mice range from 152 to 488 mg/kg i.p. and for compounds 21 to 23, the p.o. values are 484, 500 and 525 mg/kg. The relative toxicity of compounds 1 to 7 and 14 to 20 showed inverse ratio in their numbers. Basic compounds 21 to 23 at high dose levels (64 mg/kg i.p.) induced only hypnotic depression. No change was observed in organ-wise histopathological study except patchy necrosis at the site of injection of basic compounds. The CNS pharmacological studies were negative with reference to anti-convulsion, analgesic, antipyretic tests by conventional methods except at higher doses (32 or 64 mg/kg i.p.), which exhibited synergistic effects in mice and rats.

Analgesics↗
PubMed1984

In-vivo accuracy of ultrasound measurements of intrauterine volume in pregnancy.

The accuracy of ultrasonic measurements of intra-amniotic volume using a parallel planimetric area method was assessed in 18 women by comparison against different measures of the same volume space. In nine patients undergoing second-trimester termination of pregnancy amniotic fluid volume was measured using a dye dilution method and fetal volume was measured by either water displacement or calculated from fetal weight. The estimated intra-amniotic volume by this method was not significantly different from the ultrasonic measurement. In one patient who had a hysterotomy, fetal and amniotic fluid volumes showed a difference of 1.01% between ultrasonically-measured and actual intra-amniotic volume. In eight patients studied in the third trimester the mean difference between ultrasonic and estimated intra-amniotic volume at delivery was 6.2%.

Amnion↗
PubMed1984

Longitudinal and transverse uterine area measurements (LTUA) are not representative of intrauterine volume.

A midline longitudinal area and the maximum transverse area of the pregnant uterus were used to compute the intrauterine volumes of 37 women in the third trimester of pregnancy. The results were compared with measurements done simultaneously using a parallel planimetric area method. The use of only two areas caused significant underestimation of total intrauterine volume, by 14-36 per cent. Because of the variable shape of the uterine cavity in pregnancy, the product of longitudinal and transverse intrauterine area measurements cannot give reliable information about intrauterine volume.

Female↗
PubMed1984

Obstetric management of preterm labour.

In recent years the trends in the obstetric management of preterm labour have moved in the direction of more active policies with greater use of fetal heart monitoring and Caesarean section to avoid traumatic and asphyxial damage to the baby. Conservative management still has an important place, especially in association with extreme prematurity. Following initial enthusiasm, the use of tocolytic drugs and antenatal corticosteroids are going through a phase of re-evaluation and careful assessment is essential in individual cases to avoid their inappropriate use. Future developments in the obstetric management of preterm labour will depend upon careful evaluation studies which examine not only the short-term mortality statistics but also the long-term effects in respect of neurological and developmental handicap. This task is one of the major challenges for obstetricians to tackle over the next two decades.

Adrenal Cortex Hormones↗
PubMed1984

Perturbation of the direction of neurite growth by pulsed and focal electric fields.

We have studied the orientation of neurite growth in the culture of embryonic Xenopus neurons in response to three types of extracellular electric fields: spatially uniform pulsed fields, focally applied steady (DC) fields, and focally applied pulsed fields. Under uniform pulsed fields, neurites showed a preferential orientation toward the cathode pole of the field in a manner similar to that previously found for DC fields. The extent of neurite orientation depended upon the duration, amplitude, and frequency of the pulse but appeared to be similar to that produced by a uniform DC field of an equivalent time-averaged field intensity. For square pulses of 5 msec duration, the minimal amplitude and frequency required to produce a detectable orientation of neurite growth over a period of 24 hr were 2.5 V/cm and 10 Hz, which correspond to a time-averaged field intensity of 125 mV/cm. Steady or pulsed focal fields were applied by passing a current through a micropipette placed near the growth cone of the neurite. Fields of negative polarity (current sink) were found to attract the growth cone, whereas fields of positive polarity (current source) were found to deflect the growth cone away from the pipette. The threshold DC current density needed at the growth cone to perturb its direction of growth within 15 min was 0.2 to 2 pA/micron2 (or 3 to 30 mV/cm); and for focal pulsed currents (pulse duration 5 msec), a typical combination of minimal pulse amplitude and frequency was 4 pA/micron2 and 10 Hz. This threshold focal current is similar to that which occurs at the synaptic cleft during active synaptic activity.

Animals↗
PubMed1980

Reduction of barbiturate anaesthesia by new glutarimide compounds in mice.

Newly synthesized glutarimide compounds (Table 1) at doses of 4, 8 and 16 mg/kg (IP) reduced the duration of sleep induced by pentobarbitone in mice. Compounds 1 to 7 and 21 were more potent than the other compounds and their activity was comparable to the reference drug, bemegride. The structure activity relationship for the decrease in duration of barbiturate anaesthesia caused by the various groups of these compounds was mainly found to be inversely related to the length of the alkyl side chain at position 4 of the beta carbon atom. It was also shown that the presence of piperidine, diethylamine and morpholine moieties attached to 3,5-dicyanoglutarimide was partly responsible for the reduction in barbiturate anaesthesia by these compounds.

Animals↗
PubMed1978

Ganglionic action of some newly synthesized glutarimide compounds.

20 newly synthesized glutarimide compounds and their organic bases were investigated for their action on the autonomic ganglion in cats. Compounds 1 to 7 having piperidine moiety showed mainly ganglionic stimulant activity as evidenced by rise in blood pressure, contraction of nictitating membrane and rise in urinary bladder pressure of cats, which was completely blocked by C6 and partly by atropine. Compound 8 and 9 having diethylamine moiety showed initial stimulation--followed by blockade of the autonomic ganglia. Compounds 10 to 13 having morpholine moiety showed stimulation of both sympathetic and parasympathetic autonomic nervous system. The responses were due to effect partly on ganglia and partly on the receptors. Compounds 14 to 20, which have alkyl substitution chain at position 4 of beta-carbon atom, showed depressor action. The ganglionic activity of the glutarimide compounds in various groups was found to be in inverse ratio to the length of the alkyl side chain at position 4 of the beta-carbon atom.

Animals↗
PubMedDate not supplied

A double-blind controlled trial of PGE2 gel in cervical ripening.

A double-blind controlled trial of intracervical prostaglandin E2 gel was carried out in patients with an unripe cervix. Half of the treated group, compared to 8.6% of the controls became established in labor before planned amniotomy. There was no significant improvement in the state of the cervix in the remaining patients and the outcome of labor was not improved in the treated group in terms of fetal distress or cesarean section.

Adult↗
PubMedDate not supplied

Epidural analgesia and its effect on umbilical artery flow velocity waveform patterns in uncomplicated labour and labour complicated by pregnancy-induced hypertension.

Umbilical artery flow velocity waveforms were obtained using continuous-wave Doppler ultrasound to examine the effect of epidural analgesia on peak systolic/least diastolic ratio (A/B ratio) in 38 women in uncomplicated labour, and 12 women with pregnancy-induced hypertension (PIH). In the uncomplicated group there was no significant change in A/B ratio after epidural analgesia, but in the PIH group there was significant correlation between the fall in mean blood pressure and the fall in A/B ratio at 30 min after induction of epidural analgesia (r = 0.85, p less than 0.001). This suggests that epidural analgesia in PIH is associated with a reduction in placental resistance and may be beneficial to the fetus.

Analgesia, Epidural↗
PubMedDate not supplied

Are 'notched' uterine arterial waveforms of prognostic value for hypertensive and growth disorders of pregnancy?

In a case-control controlled study of 86 women identified as having bilaterally 'notched' uterine arterial waveform patterns at 18 weeks, the presence of bilateral 'notched' uterine arterial waveforms at that time was associated with the subsequent development of hypertension and small-for-gestational-age infants, but the predictive value was poor. For those women in whom the bilateral uterine 'notches' were observed to persist to 24 weeks, the relative risk of developing proteinuric hypertension increased 14 times, and in these women the positive predictive value for the subsequent development of hypertension increased to 58.6% when compared with their matched controls. The identification of women with persistent bilateral uterine 'notches' provides a means of identifying women at significant risk of hypertensive and growth disorders at a stage when therapeutic intervention aimed at limiting the severity of the disease and its associated complications could be commenced.

Arteries↗