Biomedical subjects
Publications and source records attributed to J M Pearce.
A retrospective study was made of 96 patients diagnosed as cranial arteritis of whom 32 were accepted using strict clinical criteria or a positive temporal artery biopsy. Unusual presentations of fever, psychiatric illness, headache-free patients and a 'normal' ESR are described. The recognition of these variations is important in the early diagnosis of temporal arteritis.
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The routine method of induction at Queen Charlotte's Maternity Hospital is now by the use of prostaglandin E2 pessaries. The first 502 consecutive patients thus induced are presented: the caesarean section rate for a failed induction with an unfavourable cervix has fallen to 2%. The prostaglandin E2 pessary is highly efficient and acceptable for all cases in which a simple amniotomy will not suffice.
Vaginal pessaries containing 3 mg of prostaglandin E2 were used to induce labour in 200 patients with variable induction features. Prostaglandin-induced labour was augmented where necessary by synthetic oxytocin. There was on failed induction. Only 23% of patients with favourable induction features and 53% of patients with unfavourable features needed oxytocin. There were no adverse fetal or maternal effects. The prostaglandin E2 pessary was as effective in inducing labour as 350 microgram extra-amniotic prostaglandin E2 in tylose in a comparable group of 200 patients in which there were 4 failed inductions.
In each of two experiments rats learned a discrimination between a stimulus (A) that signaled shock and a compound stimulus (AB) that signaled no shock. In Experiment 1 it was found that the AB compound acquired excitatory strength only slowly when, in a second phase of training, it was made to signal the occurrence of shock. In Experiment 2 the acquisition of inhibitory strength by the compound was similarly found to be retarded. This second experiment also replicated the results of Experiment 1. The relevance of these results to current theories of latent inhibition and attention is discussed.
In each of three experiments rats were trained by the conditioned-emotional-response technique with a conditioned stimulus (CS) predicting a relatively weak shock, the unconditioned stimulus (US). In the second stage of training the intensity of the shock was increased, and it was found that subjects for whom the same CS was used in both stages acquired further suppression less readily than subjects that experiences a new CS in the second stage. The implication of these results for theories of attention and for theories of habituation is discussed. It is suggested that associations formed by the test CS during the first stage of training reduce the readiness of the stimulus to enter into new associations, either because an association between the stimulus and the context reduces further processing of the stimulus or because the association between the test stimulus and the weak shock attenuates the formation of an association with the stronger shock.
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A review of the effects of using bromocriptine in Parkinson's disease showed that it rarely helps patients not primarily improved by levodopa. Patients who show late failure with levadopa and whose response to treatment is declining are helped by combining the two drugs. High cost and severe psychosis are the main disadvantages of bromocriptine, and, although it is not recommended for patients who are doing well on levodopa, it is the best available drug for hospital use in patients who show late failure with levodopa.
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1. Four major enolase isozymes have been identified in human tissues and are referred to as L, M, 'intermediate' and 'fast'. The M isozyme is the major form found in skeletal muscle and heart extracts and the L isozyme the major form found in extracts of liver and most other tissues. The 'intermediate' and 'fast' isozymes are most active in brain but are observed as weak components in most other tissues including heart but are not seen in skeletal muscle. It was observed that during fetal development of heart and skeletal muscle the L form declines in activity while the M form increases in activity. 2. The kinetic properties, heat stabilities and molecular sizes of the main enolase isozymes have been compared. Although the isozymes share many features in common, the 'fast' isozyme is more stable when subjected to heat treatment than either the L or M isozymes. Further, the 'fast' isozyme retains its dimeric structure and activity in the absence of magnesium ions while the L and M isozymes dissociate and lose activity. The 'intermediate' isozyme has properties which are intermediate to those of the L and 'fast' isozymes. 3. The 'intermediate' isozyme can be partially dissociated to equal quantities of L and 'fast' isozymes by storage at room temperature or by freezing and thawing in the presence of 2 M-NaCl. Conversely, mixtures of L with 'fast' and M with 'fast' give rise to an 'intermediate' isozyme after freezing and thawing. 4. Evidence derived from this study has led to the suggestion that three separate gene loci are involved in the determination of human enolase. It is proposed that one of these, ENO1, determines the L isozyme which is the homodimer alphaalpha; another locus, ENO2, determines the 'fast' isozyme which is the homodiner betabeta; and the third locus, ENO3, determines the M isozyme which is the homodimer gammagamma. The 'intermediate' isozyme seen as a strong component in brain and as a weak component in most other tissues is thought to be the heterodimer alphabeta. In heart however it is probably mainly betagamma.
Two experiments are described in which rats received a series of shock and food presentations in a Pavlovian counterconditioning sequence. Subsequently, the capacity of the shock to act as a reinforcer during conditioned emotional response (CER) training was assessed. In the first experiment, following each shock during counterconditioning by a food presentation was found to retard the development of suppression during CER training relative to control conditions in which different groups of rats received either a sequence of explicitly unpaired shock and food presentations, shock presentations alone, or food presentations alone. The second experiment demonstrated that when the magnitude of the food presentations is held constant, the attenuation of the suppressive properties of shock by pairing with food depends on the magnitude of the shock. The results are interpreted as demonstrations of Pavlovian counterconditioning, which, it is suggested, modifies the general aversiveness of a noxious stimulus.
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Ultrasound scanning during the second trimester of pregnancy revealed cysts of the choroid plexus in the posterior horn of the lateral ventricle in five cases. All disappeared spontaneously between 20 and 23 weeks and normal infants were subsequently delivered.