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Biomedical subjects

J M Pearce

Publications and source records attributed to J M Pearce.

At least 217 records · Page 12Linked to original sources
PubMed1987

A comparison of symphysis-fundal height and ultrasound as screening tests for light-for-gestational age infants.

The clinical efficiency of serial measurement of symphysis-fundal height (SFH) for the prediction of light-for-gestational age (LGA) infants was compared with that of a single measurement of fetal abdominal circumference (AC) by ultrasound in the third trimester. To make the tests comparable the lower cut-off point of AC was altered until the specificity matched that of SFH. The sensitivity of the AC measurement (83%) was slightly better than that of the SFH measurement (76%) but this difference was not statistically significant. Each test had a false positive rate of about 60% which is comparable with clinical assessment. Screening with both tests and predicting LGA with abnormal results from either test improved the sensitivity to 93% but, as expected, decreased the specificity to 67% and the positive predictive value to 32%. If ultrasound facilities permit both tests should be used otherwise SFH measurements only could screen for LGA with ultrasound back-up for those with low SFH results.

Abdomen↗
PubMed1987

Ultrasonically guided percutaneous umbilical blood sampling in the management of intrauterine growth retardation.

Ten patients, hospitalized because of severe asymmetrical fetal growth retardation before 32 weeks gestation, underwent ultrasonically guided percutaneous umbilical blood sampling because of concern over the fetal heart rate trace. In eight patients the fetus was judged to be acidotic and they were delivered immediately by caesarean section. In two patients the fetus was not considered to be acidotic and the pregnancy was allowed to go on. In those babies that were delivered the pH blood collected from the umbilical vein at the time of delivery was compared to the antenatal sample. There were no significant differences. The technique of antenatal umbilical vein blood sampling is readily learned and by assessment of fetal acid base status a more precise diagnosis can be made leading to appropriately planned management.

Acidosis↗
PubMed1987

Modern treatment of Parkinson's disease.

Both general measures and a variety of drugs serve to improve the quality of life in the Parkinsonian patient. Meticulous neurological supervision is required to monitor response and the many drug-induced side-effects.

Aged↗
PubMed1987

Pavlovian analysis of interactions between hunger and thirst.

In four experiments we examined the effect of an irrelevant drive on classical conditioning with food and water. In the first experiment the irrelevant drive weakened the conditioned response in extinction. In Experiments 2 and 3, this suppressive effect was found also in acquisition. Furthermore, the presence of an irrelevant drive during nonreinforced presentations of the conditioned stimulus was found to protect the conditioned response from extinction. Experiment 4 showed that the depressive effect of the irrelevant drive is manifested only when the relevant drive is present. Taken together, these results suggest that an irrelevant drive can influence conditioned responding by modulating the representation of the unconditioned stimulus.

Animals↗
PubMed1986

Prolonged pregnancy: the management debate.

A prospective trial was conducted to compare the effects of conservative management of prolonged pregnancy (conservative group) with routine induction of labour at 42 weeks' gestation (active group) in otherwise uncomplicated pregnancies. Of the 402 pregnancies studied, 207 (51%) were allocated to conservative management and 195 (49%) were allocated to have labour induced. The groups were well matched for age, parity, and smoking habits. One hundred and sixty six (80%) of the patients in the conservative group went into spontaneous labour. Of the remainder, two underwent elective caesarean section, 19 had labour induced because of clinical concern, and the remaining 20 had labour induced at the patient's own request. One hundred and twenty five (64%) of the patients in the planned active group underwent induction of labour. Of the remaining 70, 49 went into spontaneous labour and 21 (11%) asked that they should not have labour induced. Comparison of the two groups showed no difference in the length of the first stage of labour but a trend towards an increased need for intervention for fetal distress (p less than 0.06) in the active group. There were no differences in the length of the second stage, the need for intervention, or the mode of delivery. In terms of Apgar scores the neonatal outcome was not significantly different between the two groups, but a greater proportion of the babies (15% v 8%) in the active group required intubation. Umbilical cord venous pH estimated in the last 183 consecutive deliveries in the study showed a significantly lower mean value in the active group (p less than 0.05). There was no difference in birth weight between the two groups. Two deaths occurred in the study. There was a stillbirth in the conservative group at 292 days after massive abruption, and one neonatal death in the active group owing to multiple congenital abnormalities. The outcome for mother and baby in patients from both groups who went into spontaneous labour was generally good. The outcome for patients for whom conservative management was planned but induction became necessary was no different from that of patients who underwent planned induction at term. Thus from our results we can find no evidence to support the view that women with normal prolonged pregnancy should undergo routine induction of labour at 42 weeks' gestation.

Apgar Score↗
PubMed1986

Qualitative assessment of uteroplacental blood flow: early screening test for high-risk pregnancies.

A pulsed Doppler apparatus was used to assess the blood flow velocity profiles in uterine vessels (arcuate arteries) at 16 to 18 weeks' gestation to determine if complications associated with impaired trophoblastic invasion of the placental bed (ie, pregnancy-induced hypertension, intrauterine growth retardation, and fetal asphyxia) could be predicted by this measurement. Thirty-one of 126 consecutive pregnancies developed one or more of the above complications. The sensitivity was 68% and the specificity 69%; the predictive value of a positive test was 42% and that of a negative test 87%. These results seem to represent an improvement over existing predictive techniques. Early identification of such a high-risk group might allow more discerning use of antenatal resources and may lead to new therapeutic measures.

Blood Flow Velocity↗
PubMed1986

Delivery of the very low birthweight baby.

The outlook for the baby weighing less than 1500 g at birth has dramatically improved over the last decade largely due to advances in neonatal intensive care. This, however, has created new clinical dilemmas in obstetric management and delivery. This article provides a critical review of published work, highlights the questions that remain unanswered and suggests guidelines for clinical management in the light of current knowledge.

Anesthesia, Obstetrical↗
PubMed1985

Is migraine explained by Leao's spreading depression?

Spreading depression (SD) is a severe but transient disruption of neural activity in the brain, which spreads like waves in a pond in which a stone has been cast. It propagates to normal tissues and is accompanied by flux of Na+, Ca++, and Cl- ions into the cells, resulting in a brief burst of action potentials followed by electrical silence. Its rate of spread correlates almost exactly with the observed spread of the aura of classical migraine. It is accompanied in animal experiments by changes in regional cerebral blood flow which closely simulate changes observed in man during the migraine aura. There are serious difficulties in extrapolating from SD in animals to migraine in man, but the possibility of SD as the initiating event accords with the notion of migraine as a cerebral (neural) disorder and encourages further investigation in man.

Brain↗