PubMed Health⌕ Search

Biomedical subjects

P Lovell

Publications and source records attributed to P Lovell.

5 recordsLinked to original sources
PubMed2002

Synaptic precedence during synapse formation between reciprocally connected neurons involves transmitter-receptor interactions and AA metabolites.

The cellular mechanisms that determine specificity of synaptic connections between mutually connected neurons in the nervous system have not yet been fully examined in vertebrate and invertebrate species. Here we report on a novel form of synaptic interaction during early stages of synapse formation between reciprocally connected Lymnaea neurons. Specifically, using soma-soma synapses between an identified dopaminergic neuron (also known as the giant dopamine cell), right pedal dorsal 1 (RPeD1), and a FMRFamidergic neuron, visceral dorsal 4 (VD4), we demonstrate that although reciprocal inhibitory synapses re-form between the somata after 24-36 h of pairing, VD4 is, however, the first cell to establish synaptic contacts with RPeD1 (within 12-18 h). We show that VD4 "captures" RPeD1 first as a postsynaptic cell by suppressing its transmitter secretory machinery during early stages of cell-cell pairing. The VD4-induced suppression of transmitter release from RPeD1 was transient, and it required transcription and de novo protein synthesis dependent step in VD4 but not in RPeD1. The VD4-induced effects on RPeD1 were mimicked by a FMRFamide-like peptide. Perturbation of FMRFamide-activated metabolites of the arachidonic acid pathway in RPeD1 not only prevented FMRFamide-induced suppression of transmitter release from the giant dopamine cell but also shifted the synaptic balance in favor of RPeD1, thus making it the first cell to begin synaptic transmission with VD4 within 12-18 h. A single RPeD1 that had developed dopamine secretory capabilities overnight and was subsequently paired with VD4 for 12-18 h was, however, immune to VD4-induced suppression of transmitter release. Under these experimental conditions, both cells developed mutual inhibitory synapses concurrently. Taken together, our data provide evidence for novel synaptic interaction between reciprocally connected neurons and underscore the importance of transmitter-receptor interplay in regulating the timing of synapse formation in the nervous system.

Animals↗
PubMed1996

The effect on patients of non-referral for skull radiography following mild head injury.

This paper assesses the attitude of 705 patients who attended the Accident department of a large metropolitan district general hospital, with a mild head injury and who were not referred for skull radiography. A questionnaire was sent to patients 5-7 months after they had attended. Fifty-one per cent had expected an X-ray, and when this did not occur, the majority of this group (63 per cent) left the Accident department disappointed. Furthermore, the duration of symptoms in this group was prolonged. The introduction of guidelines may reduce clinically unnecessary X-ray examinations, but some of the consequences may not be fully appreciated. In this study, a significant number of patients were dissatisfied with the lack of X-ray referral. The main cause for the associated prolongation of symptoms is not clear, but a contributory factory may be that lack of referral for radiography led to anxiety concerning the thoroughness of their management.

Attitude to Health↗
PubMed1996

Illness behavior and somatization in general practice.

In the primary care setting, the early recognition that a patient has psychological problems is frequently hindered by the deceptive mode of presentation known as somatization. In a cross-sectional survey of patients attending suburban General Practitioners in a large metropolitan city, the General Health Questionnaire-30 (GHQ-30) and the Illness Behavior Questionnaire (IBQ) were completed by 201 patients. A comparison was made between somatizing and nonsomatizing patients with new inceptions of illness in terms of the risk of the presence of a mild nonpsychotic psychiatric illness and aspects of illness behavior. For the group as a whole, somatizing patients were more likely to be older and female. Male somatizers differed from male nonsomatizers by showing greater disease conviction and affective disturbance and more readiness to acknowledge difficulties in their lives other than health problems. No differences were found between female somatizing and nonsomatizing patients. We conclude that, while male patients who somatize psychological distress may be distinguished from male nonsomatizers early in their illness, in terms of their illness behavior, these differences are not seen as early distinguishing characteristics in female patients who present to their General Practitioners with physical problems for which no organic cause can be established.

Adult↗
PubMed1995

Posters for accident departments: simple method of sustaining reduction in x ray examinations.

OBJECTIVE: To assess whether a simple strategy would sustain a reduction in the number of unnecessary x ray examinations. DESIGN: Use of posters to display guidelines encouraging the more effective use of radiology in patients with head injuries, twisted ankles, neck injuries, and abdominal pain. SETTING: Accident department of a large metropolitan district general hospital. PATIENTS: 15,875 patients attending the accident department over two years. MAIN OUTCOME MEASURE: Proportion of patients having radiography. RESULTS: Referrals for skull radiography fell from 56% to 20% and those for abdominal radiography fell from 31% to 7%. Referral patterns for adults attending with twisted ankles and cervical spine injuries did not change. Reductions were sustained over two years. CONCLUSION: Carefully designed posters provide a simple method of reducing unnecessary x ray examinations.

Audiovisual Aids↗