Cardiac transplantation at Harefield Hospital.
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Adolescent↗
Biomedical subjects
M Fitzgerald
Publications and source records attributed to M Fitzgerald.
Episodic arthropathy in adult cystic fibrosis.
Five (8.5 per cent) of 59 adult patients with cystic fibrosis described a characteristic arthropathy which was episodic, self-limiting and polyarticular, affecting large and small peripheral joints without evidence of progression to joint damage. The five patients with arthropathy did not differ from the remaining 54 with respect to manifestations of cystic fibrosis. Synovial fluid obtained from two patients during acute episodes was clear, viscous and contained no cells. Biopsies of synovial membrane from the same patients demonstrated prominent congested blood vessels with some synovial oedema, but no evidence of inflammation. Immunofluorescent staining of synovial membrane demonstrated characteristic intimal deposition of immunoglobulin in the vessels. In one of the two patients acute arthropathy was accompanied by transient cutaneous vasculitis, circulating immune complexes and lowered serum complement levels, which suggests that the episodic arthropathy in at least some patients with cystic fibrosis is mediated by an immune mechanism.
Adolescent↗
Somatotopic organization of cutaneous afferent terminals and dorsal horn neuronal receptive fields in the superficial and deep laminae of the rat lumbar spinal cord.
The somatotopic organization of A- and C-afferent fibre terminals in the dorsal horn of the rat lumbar spinal cord was compared with the spatial location of second-order dorsal horn neuronal mechanoreceptive fields. The central terminal fields of the sural, saphenous, and tibial nerve were mapped by labelling the nerves with horseradish peroxidase (HRP). A previous study used the transganglionic transport of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) to produce a somatotopic map of high-threshold C-fibre terminal fields in lamina II (Swett and Woolf: J. Comp. Neurol. 231:66-77, '85). In the present study the terminal fields of low-threshold A beta afferents that terminate in laminae III and IV were mapped by using unconjugated HRP at prolonged survival times (72 hours). Unfixed tissue was used to increase the sensitivity of the tetramethylbenzidine reaction, thus allowing these afferent terminals to be clearly seen. The general spatial arrangement of the terminal fields in laminae III/IV closely resembled that found in lamina II in the mediolateral and rostrocaudal planes but because of a dorsoventral obliquity of the afferent terminals, the superficial and deeper fields are not in strict vertical register. The input to laminae II-IV of the dorsal horn may therefore be viewed as two horizontally arranged sheets of afferent terminals both accurately representing the skin surface, the more superficial sheet representing the high-threshold C-afferents and the deeper sheet, low-threshold A-beta afferents. The spatial organization of high-threshold A-delta afferents in laminae I and V appears to be quite different, with a transverse rather than a longitudinal orientation. To study dorsal horn cell receptive field organization two single units with mechanoreceptive fields were recorded extracellularly in each of 87 vertical tracks in the lumbar spinal cord, one unit in the superficial dorsal horn and the second in the deep dorsal horn. In general the somatotopic organization of the receptive fields of both sets of units followed that of the afferent terminal fields but there were cells with receptive fields that were anomalous relative to the recording site. No evidence of any vertical relation or columnar arrangement in receptive field size, threshold, or location on the body surface was found when comparing the two units in a pair. Furthermore, no laminar functional specialization was found, the majority of neurones having both low- and high-threshold inputs.(ABSTRACT TRUNCATED AT 400 WORDS)
Action Potentials↗
A study of behavioural deviance in 10 and 11 year old Irish school girls in an urban area.
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Child↗
The functional development of descending inhibitory pathways in the dorsolateral funiculus of the newborn rat spinal cord.
The postnatal development of descending inhibition in the spinal cord has been studied in the rat. Electrophysiological recordings were made in neonatal rat pups of the activity in single lumbar dorsal horn cells evoked by stimulation of the skin of the hindlimb. Descending inhibition was tested by observing the effect of stimulation of the dorsolateral funiculus (DLF) at thoracic level on the dorsal horn cell responses. In adults the DLF is known to contain descending axons from the brainstem which inhibit dorsal horn cell activity. Such inhibition was always observed in days 22-24 rat pups. At 18 days of age it was present but required higher-intensity stimulation to produce an effect. On day 12 only half the dorsal horn cells tested were inhibited by DLF stimulation and then only weakly. On day 9 no cells were inhibited. Application of horseradish peroxidase to DLF axons in the lumbar cord resulted in retrograde labelling of cells in the medulla, pons and midbrain. The labelling on day 6 was comparable to the adult. The results show that despite the early anatomical existence of a descending DLF pathway, there is no functional descending inhibition until days 10-12 of life. It is suggested that this is due to delayed maturation of crucial interneurones in the dorsal horn or to insufficient levels of 5-hydroxytryptamine or other neurochemicals in the descending DLF axon terminals.
Aging↗
The relationship between the dentist's year of graduation and ordering of bitewing radiographs.
This article reports the results of a survey of general practice dentists on the relationship of the dentist's year of graduation to the ordering of bitewing radiographs for patients. More recent graduates were more likely to indicate ordering the radiographs at 6-month intervals. There were no differences in ordering associated with the dentist's experience. Shorter intervals between ordering were indicated by all dentists for patient groups at high risk of caries.
Adolescent↗
The sprouting of saphenous nerve terminals in the spinal cord following early postnatal sciatic nerve section in the rat.
Transganglionic labelling of the saphenous nerve in rats with WGA-HRP revealed the central distribution of its terminals in the lumbar dorsal horn. The terminal field was clearly defined and consistent in rats aged between day 6 and day 90. If, however, the sciatic nerve was sectioned on day 1 of postnatal life, the saphenous terminal field expanded to occupy twice the normal area (measured between the L2 and L4 boundaries). The spread was caudal, medial, and lateral into areas normally occupied by sciatic nerve terminals. This sprouting was very weak if the sciatic nerve was sectioned later in postnatal life, on day 5, and nonexistent if sectioning took place on day 10. Crushing the sciatic nerve on day 1 also triggered the effect but the spread of the terminal field was less than that produced by section of the sciatic nerve. There was no evidence of sprouting from the contralateral intact sciatic nerve. The results demonstrate the necessity of intact afferent input during a critical period of neonatal life in order to maintain the precise somatotopic termination pattern of dorsal root afferents.
Aging↗
Plasticity of acid phosphatase (FRAP) afferent terminal fields and of dorsal horn cell growth in the neonatal rat.
Peripheral nerve section results in depletion of fluoride-resistant acid phosphatase (FRAP) from the nerve terminals in the dorsal horn of the spinal cord (Schoenen et al., '68) and this has been used in the past to map the termination field of individual nerves (Rustioni et al., '71; Devor and Claman, '80). In the present study we show that a similar central depletion occurs following sciatic nerve section or crush in neonatal rats. Unlike adults, however, the area of depletion is rapidly filled by sprouting of FRAP-containing afferent terminals from nearby intact peripheral nerves. The sprouting is extensive but never completely fills the depleted area. After nerve crush there is some recovery of FRAP from the sciatic nerve terminals themselves as well as from nearby nerve terminals. The source of recovered FRAP is demonstrated by resectioning or recrushing the nerves. The sprouting occurred when the sciatic was injured on day 1 but failed to take place when the injury was applied on or after day 10. Sciatic nerve section on day 1 also produces marked growth retardation of the ipsilateral dorsal horn gray matter that becomes more apparent as the rat matures. Nerve crush produces a less marked shrinkage that is slower in onset. If the nerve is crushed repeatedly, however, so that regeneration is prevented, the shrinkage is analogous to that following nerve section. No shrinkage occurs if the nerve is cut or crushed on day 10. The results show that separation of the spinal cord from its peripheral input at a critical stage in development results in disruption of the somatotopic organization of the C fibre afferent input to the dorsal horn and in slowing of growth of the dorsal horn gray matter.
Acid Phosphatase↗
The release of lyso-PAF from guinea-pig lungs.
Lyso-PAF was detected after ionophore challenge in the effluent of lungs of guinea-pigs exposed to oxygen and perfused through the pulmonary circulation as well as of control lungs perfused through the airways. Lyso-PAF is probably the inactive metabolite of PAF-acether which could not, itself, be detected in the lung effluents.
Animals↗
Nerve growth factor counteracts the neurophysiological and neurochemical effects of chronic sciatic nerve section.
The sciatic nerve was sectioned unilaterally in rats and nerve growth factor (NGF) applied locally to the nerve stump for the following 10-14 days using an indwelling osmotic pump. The aim of the experiment was to test whether NGF had any effect on the previously reported neurophysiological and neurochemical events that occur central to a peripheral nerve lesion. The method of application allowed the sciatic nerve on the other side to be used as a control. Primary afferent depolarization fell, as expected, to 13% of its control value after chronic nerve section but if NGF was administered it fell to only 43.5% of control. Chronic nerve section is also known to result in expansion of the receptive fields of deafferented dorsal horn cells. NGF treatment reduced the number of such large receptive fields by 50%. The normal depletion of fluoride resistant acid phosphatase from the cut nerve terminals in the dorsal horn did not occur following NGF treatment. Radioimmunoassay of substance P revealed that the 30% reduction in dorsal horn levels that follows chronic sciatic nerve section did not occur when NGF was applied and that the accompanying 60% decrease in dorsal root ganglion levels was changed to a 64% increase by NGF. The results show that chronic NGF treatment of a cut sciatic nerve does partially reverse the central changes that normally follow deafferentation.
Acid Phosphatase↗
Behaviourally deviant pre-school children and depressed mothers.
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Adult↗
Histological evaluation of microfilled and conventional composite resins on monkey dental pulps.
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Animals↗
Pulp capping of dental pulp mechanically exposed to oral microflora: a 1-2 year observation of wound healing in the monkey.
Four adult Rhesus monkeys provided 120 teeth for buccal Class V cavities. Twenty-nine were non-exposed controls and 91 were exposed for 3 intervals. All 120 teeth were capped with a hard set Ca(OH)2 medicament, restored with amalgam, 57 evaluated after 1 year and 63 after 2 years. Of the 91 exposed pulps, 45 showed complete healing, 25 showed pulpal inflammation varying from acute to chronic, 12 showed severe pulpal breakdown and abscess formation and 9 were necrotic. No difference was observed in the healing response between the 3 exposure times. New hard tissue formed at, or subjacent to, the medicament in 77 of 91 exposed pulps with a tunnel defect frequently present, running from the medicament interface to the pulp. This study demonstrates that recurring pulp inflammation observed after 1 & 2 year direct pulp capping, is associated with bacterial contamination.
Animals↗
The post-natal development of cutaneous afferent fibre input and receptive field organization in the rat dorsal horn.
The responses evoked in lumbar dorsal horn cells by both natural and electrical hind-limb skin stimulation were recorded in the spinal cord of rat pups aged 0-15 days under urethane anaesthesia. The input volley was recorded on the L4 dorsal root and consisted of two separate waves from birth. Latency and threshold measurements were consistent with these two waves being immature A (myelinated fibre) waves and C (non-myelinated fibre) waves. On the first 3 days of life background activity of cells in the dorsal horn was low and evoked discharges were sluggish. On electrical stimulation of the skin, neonatal dorsal horn cells frequently responded with only 1 or 2 impulses per input volley with long central delays of up to 20 ms. Synaptic linkage appeared weak and many cells failed to follow stimulation rates of 5 Hz. Natural skin stimulation showed that the majority of cells at days 0-3 responded to pinching the skin only. The development of responses evoked by C fibres in the dorsal horn was delayed compared to that of responses evoked by A fibres. Short and long latency responses corresponding to the early A and late C afferent input volleys could be recorded in the superficial laminae (I, II and III) of the dorsal horn from day 0, but in the deeper laminae only early short latency A responses were evoked until the age of day 7-8. After this time, a long latency C response also appeared and increased in strength with age. Convergence of low and high threshold inputs onto dorsal horn cells was rare at birth but increased gradually over the following two weeks. Receptive field areas, mapped by natural mechanical stimulation of skin, were large at birth and decreased in size with age. At birth the mean receptive field area was 14.2% of the total hind-limb area whereas at day 15 it was 3.6%. This fall in size was particularly marked in cells of the deep dorsal horn. Pinching or brushing the receptive field of many neonatal dorsal horn cells resulted in long-lasting after-discharges (30-90 s) which on days 0-3 could be more pronounced than the initial evoked response. The duration and amplitude of these responses decreased with age. Repetitive electrical skin stimulation of the receptive fields of these cells produced 'wind-up' and prolonged after-discharge. Ipsilateral, contralateral and distant inhibitory components to receptive fields were observed from day 0.(ABSTRACT TRUNCATED AT 400 WORDS)
Action Potentials↗
Behavioural deviance and maternal depressive symptoms in paediatric outpatients.
A consecutive series of 95 3 to 4 year old and 43 7 to 11 year old children attending surgical, and medical outpatient clinics was studied, using questionnaires that measured behavioural deviance and had adequate reliability and validity for screening populations of children. A control group was also studied in the 7 to 11 year old sample. Depressive symptoms in the mothers of the children were determined using the Wakefield depression inventory. There was considerable behavioural deviance in children attending the outpatient clinics; 44% of the 7 to 11 year olds who were surgical outpatients had deviant scores. Thirty two per cent of mothers of medical outpatients had deviant scores on the depression inventory. These findings have relevance for the approach paediatricians take to their outpatients.
Child↗
Ameboid receptive fields of cells in laminae 1, 2 and 3.
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Animals↗
The spread of sensitization of polymodal nociceptors in the rabbit from nearby injury and by antidromic nerve stimulation.
1. Ninety-three polymodal nociceptor units with unmyelinated axons were isolated from rabbit sural nerves. Twenty-three were used for control data. These showed normal sensitization on repeated heating of their receptive fields, measured here as a drop in mean heat threshold. 2. Small injuries were made 5 (n = 15) or 10 (n = 12) mm outside the receptive fields of some polymodal nociceptors. This resulted in the development of spontaneous firing and lowered thresholds to heating of the receptive field. 3. Local anaesthetic previously injected into the site of injury blocked this spread of heat sensitization. Previous injection of saline had no effect. 4. Antidromic stimulation of the sural nerve, proximal to the recording site, also resulted in heat sensitization of polymodal nociceptors (n = 10). 5. Possible mechanisms for the spread of sensitization of polymodal nociceptors from nearby injury are discussed. Analogies are drawn between these results and those of Lewis (1935--36) on the spread of cutaneous ;yperalgesia around a skin injury in man.
Action Potentials↗
Cellular mechanics of dentinal bridge repair using 3H-thymidine.
Cellular reorganization in the pulp following mechanical pulp exposure involves three steps: First, lysis and macrophage resolution of the clot form; second, there is an invasion of the clot area by fibroblasts and endothelial cells, i.e., formation of granulation tissue; third, an organization and differentiation of these cells into functional odontoblasts occurs as early as 9 days after exposure. Autoradiographic results showed an increased DNA synthesis in the fibroblast and endothelial cell populations which coincided with a histologically-observed increase in those populations. A relative increase in fibroblastic activity, as compared to endothelial cell activity, suggested that fibroblasts may be the cells that replace odontoblasts.
Animals↗