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Biomedical subjects

M Fitzgerald

Publications and source records attributed to M Fitzgerald.

At least 19 recordsLinked to original sources
PubMed1992

Neonatal sciatic nerve section results in thiamine monophosphate but not substance P or calcitonin gene-related peptide depletion from the terminal field in the dorsal horn of the rat: the role of collateral sprouting.

The expression of substance P, calcitonin gene-related peptide (CGRP) and thiamine monophosphatase in the sciatic nerve terminal field of the lumbar dorsal horn of the rat was examined following neonatal sciatic nerve section and ligation. The total terminal field from L3 to L5 was mapped from semi-serial sections on the treated side and compared to equivalent maps on the contralateral intact side. To obtain a detailed time course of events, data were obtained 4, 7, 10, 15-20 and 40-60 days after sciatic nerve section. At 4-7 days thiamine monophosphate was depleted from the cut nerve terminals resulting in a gap in dorsal horn thiamine monophosphate stain similar to that seen after adult nerve section. In contrast, substance P and CGRP-containing terminals showed only a transient fall in expression in the first week following nerve section and then staining was no different from that seen on the control side. The depletion of peptides normally observed after adult nerve section did not occur. This phenomenon was only observed if the sciatic nerve was cut at birth. Nerve section at 10 days of age resulted in the same pattern of peptide depletion as is observed in the adult. A week after neonatal sciatic nerve section, thiamine monophosphate-containing nerve terminals from nearby intact nerves begin to sprout into the sciatic nerve territory in the dorsal horn. This, together with some recovery of thiamine monophosphate from the remaining sciatic terminals themselves, results in a slow filling in of the gap in the thiamine monophosphate stain. Resection of the cut sciatic nerve, together with adjacent intact nerves, re-establishes the depletion. Substance P and CGRP terminals from nearby intact nerves also sprout into the deafferented sciatic field and this can be demonstrated by the larger than normal area of depletion following section of these nerves when adult. Furthermore, resection of the neonatally cut sciatic nerve when adult also causes some depletion of substance P and CGRP within the sciatic field, indicating a degree of recovery or up-regulation of peptides in surviving cut afferents. However, even after resection of the cut sciatic nerve and nearby intact nerves, substance P and CGRP staining remained in the terminal region. We conclude that while central collateral sprouting does take place in both substance P and CGRP-containing afferents following peripheral nerve section, it cannot account for the lack of depletion of peptides observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗
PubMed1992

Fractures in the under-3-year-old age cohort.

One hundred twenty-four urban children under 3 years of age admitted for fractures were retrospectively reviewed to determine the frequency of accidental and nonaccidental causes in this population. The fractures were categorized according to their mechanisms: motor-vehicle passenger or pedestrian accident, other accidents, or child abuse. There were no differences in the frequency of fractures by race, date of birth, or season in which the injury occurred. Skull fractures were most frequent (62%), followed by femur fractures (11%). There was a 26% increase in fractures between 1987 and 1989, especially in the non-motor vehicle cohort. Caretaker ignorance and/or carelessness was a common cause of fractures in the infant and toddler age group. Injuries were still occurring in spite of infant care seat use. The American public must be educated in preventive medicine and safety to decrease the senseless morbidity of our greatest resource.

Accidents↗
PubMed1992

Community education on stroke.

A programme of community education on stroke in Micronesia is based on the use of brightly illustrated posters with a limited content of written material in the native languages. This approach has been favourably received by the people.

Audiovisual Aids↗
PubMed1991

A randomised trial comparing endometrial resection and abdominal hysterectomy for the treatment of menorrhagia.

OBJECTIVE: To determine the advantages and disadvantages of endometrial resection and abdominal hysterectomy for the surgical treatment of women with menorrhagia. DESIGN: Randomised study of two treatment groups with a minimum follow up of nine months. SETTING: Royal Berkshire Hospital, Reading. SUBJECTS: 51 of 78 menorrhagic women without pelvic pathology who were on the waiting list for abdominal hysterectomy. TREATMENT: Endometrial resection or abdominal hysterectomy (according to randomisation). Endometrial resections were performed by an experienced hysteroscopic surgeon; hysterectomies were performed by two other gynaecological surgeons. MAIN OUTCOME MEASURES: Length of operating time, hospitalisation, recovery; cost of surgery; short term results of endometrial resection. RESULTS: Operating time was shorter for endometrial resection (median 30 (range 20-47) minutes) than for hysterectomy (50 (39-74) minutes). The hospital stay for endometrial resection (median 1 (range 1-3) days) was less than for hysterectomy (7 (5-12) days). Recovery after endometrial resection (median 16 (range 5-62) days) was shorter than after hysterectomy (58 (11-125) days). The cost was 407 pounds for endometrial resection and 1270 pounds for abdominal hysterectomy. Four women (16%) who did not have an acceptable improvement in symptoms after endometrial resection had repeat resections. No woman has required hysterectomy during a mean follow up of one year. CONCLUSION: For women with menorrhagia who have no pelvic pathology endometrial resection is a useful alternative to abdominal hysterectomy, with many short term benefits. Larger numbers and a longer follow up are needed to estimate the incidence of complications and the long term efficacy of endometrial resection.

Adult↗
PubMed1991

The pattern and timing of cutaneous hair follicle innervation in the rat pup and human fetus.

The postnatal development of hair follicle innervation was studied in the rat hindlimb using a silver stain which detects large and medium calibre cutaneous nerve fibres. The pattern and timing of innervation in relation to postnatal changes in follicle growth were studied providing new data on nerve-target interactions in the developing peripheral nervous system. Sensory axons begin to leave the dermal plexus and grow towards follicles at P (postnatal day) 3 but do not start to innervate them until P7 or achieve an adult appearance until P19. The first terminals are circumferential, followed some days later by the appearance of palisade endings. The number of axons innervating a hair follicle increases steadily with age until P19 and there is no evidence of exuberant innervation of follicles during development. Hair follicle density in the rat is maintained during development due to waves of small, vellus follicle growth later in postnatal life as the skin grows. The percentage of follicles innervated however, decreases from the second postnatal week onwards presumably because late developing vellus hairs do not become innervated. Comparative analysis in human fetal abdominal skin using the same silver stain reveals a similar sequence and pattern of innervation to the rat over the period of 22 to 35 weeks EGA (estimated gestational age). Human skin does not, however, undergo the late waves of follicle growth seen in the rat. Follicular density decreases and the percentage of innervated follicles increases in the third trimester of fetal life.

Animals↗
PubMed1991

GAP-43 expression in the developing rat lumbar spinal cord.

The expression of the growth-associated protein GAP-43, detected by immunocytochemistry, has been studied in the developing rat lumbar spinal cord over the period E11 (embryonic day 11), when GAP-43 first appears in the spinal cord, to P29 (postnatal day 29) by which time very little remains. Early GAP-43 expression in the fetal cord (E11-14) is restricted to dorsal root ganglia, motoneurons, dorsal and ventral roots and laterally positioned and contralateral projection neurons and axons. Most of the gray matter is free of stain. The intensity of GAP-43 staining increases markedly as axonal growth increases, allowing clear visualization of the developmental pathways taken by different groups of axons. Later in fetal life (E14-19), as these axons find their targets and new pathways begin to grow, the pattern of GAP-43 expression changes. During the period, GAP-43 staining in dorsal root ganglia, motoneurons, and dorsal and ventral roots decreases, whereas axons within the gray matter begin to express the protein and staining in white matter tracts increases. At E17-P2 there is intense GAP-43 labelling of dorsal horn neurons with axons projecting into the dorsolateral funiculus and GAP-43 is also expressed in axon collaterals growing into the gray matter from lateral and ventral white matter tracts. At E19-P2, GAP-43 is concentrated in axons of substantia gelatinosa. Overall levels decline in the postnatal period, except for late GAP-43 expression in the corticospinal tract, and by P29 only this tract remains stained.

Animals↗
PubMed1991

GAP-43 expression in developing cutaneous and muscle nerves in the rat hindlimb.

The expression of the growth associated protein, GAP-43, in developing rat hindlimb peripheral nerves has been studied using immunocytochemistry. GAP-43, is first detected in lumbar spinal nerves at embryonic day (E)12 as the axons grow to the base of the hindlimb. It is expressed along the whole length of the nerves as well as in the growth cones. GAP-43 staining becomes very intense over the next 36 h while the axons remain in the plexus region at the base of the limb bud before forming peripheral nerves at E14. It remains intense along the length of the growing peripheral nerves, the first of which are cutaneous, branching away from the plexus and growing specifically to the skin, their axon tips penetrating the epidermis of the proximal skin at E15 and the toes at E19. GAP-43-containing terminals form a dense plexus throughout the epidermis which subsequently withdraws subepidermally in the postnatal period. GAP-43 staining is also evident along the growing muscle nerves during muscle innervation, which follows behind that of skin. Axons branch over the surface of proximal muscles at E15 but do not form terminals until E17. As target innervation proceeds, GAP-43 staining declines in the proximal part of the nerve but remains intense in the distal portions. Overall GAP-43 expression in the hindlimb decreases in the second postnatal week as axon growth and peripheral terminal formation decline.

Animals↗
PubMed1991

Development of pain mechanisms.

Interest in the neural development of pain pathways and of the perception and treatment of pain in newborn infants has increased markedly in the last few years. The tremendous improvement in the survival of premature infants, particularly those weighing less than 1000 gm at birth, means that there are now a significant number of infants, many of whom require surgery, undergoing necessarily extensive traumatic procedures in intensive care units. At the same time it is becoming clear that the traditional belief of paediatricians and anaesthetists that newborn infants do not feel or remember pain and therefore need no anaesthesia or analgesia is rooted in a mixture of misconception and fear.

Acute Disease↗
PubMed1991

A physiological study of the prenatal development of cutaneous sensory inputs to dorsal horn cells in the rat.

1. The response of fetal dorsal horn cells to natural and electrical stimulation of the skin of the hindpaw was recorded in vivo from the lumbar spinal cord of anaesthetized rat fetuses still in contact with their mother via the maternal circulation. 2. Responses to electrical stimulation were obtained from embryonic day 17 (E17) but spikes were not evoked by natural skin stimulation until embryonic day 19 (E19). 3. At E19 responses were evoked by pressure or pinching the skin, but responses to low intensity brush and touch were not clear until E20. 4. Receptive fields were small and response amplitudes and frequencies initially very low. However, by E20 bursts of up to fifty spikes were recorded to a single pinch and some cells displayed responses that outlasted the stimulus by 10-15 s. 5. The development of dorsal horn cutaneous evoked spike activity and consequently the ability to transmit cutaneous sensory information to the brain therefore occurs some 2 days after the development of peripheral afferent receptive fields. It is concluded that this represents the maturation time for central synaptic connections.

Animals↗
PubMed1991

Microleakage of three cement bases.

The purpose of this study was to evaluate the ability of a glass-ionomer cement-base material to prevent bacterial penetration along the dentin interface and to compare it with two conventional cement-base materials. A total of 107 Class 5 restorations was placed in Rhesus monkey teeth by means of three test materials [zinc oxide-eugenol (ZOE), copalite varnish + zinc phosphate cement base (V + ZP), and a glass-ionomer lining cement (GI)], with unetched and unbonded resin composite used alone as a control material and as a final restoration over the test base materials. Following disinfection, Class 5 cavities were prepared on the buccal surfaces of the teeth to the inner one-half of dentin. A sterile filter-paper disk was then placed on the axial wall and covered with a Teflon disk. Next, the cavities were based to the dento-enamel junction with one of the test base materials and finally restored with unetched and unbonded resin composite. After five and 16 weeks, the filter-paper disks were retrieved and cultivated for the presence and type of bacteria. The five-week results showed positive growth in two groups: the composite-only controls and the V + ZP group. The 16-week results showed growth in all of the test groups, but only one of nine teeth showed growth in the zinc oxide-eugenol group and one of 16 teeth in the glass-ionomer group. The results of this study indicate that under the conditions tested, a glass-ionomer base was capable of minimizing bacterial penetration along the material-tooth interface.

Animals↗
PubMed1991

Childhood hospitalization for psychosocial reasons: the case of gastroenteritis.

Nonmedical factors are often important considerations when choosing treatment options for illness. High levels of childhood hospitalization are of concern for psychological as well as medical and economic reasons. This study compared medical and psychosocial attributes of children managed at home or in hospital for childhood gastroenteritis to identify factors differentiating type of care. Parents of children under two years with gastroenteritis managed at home (n = 76) or in hospital (n = 76) were interviewed. Medical details and a range of intra-family factors (e.g., parenting skills, marriage) and extra-family factors (e.g., neighborhood, social contacts) were queried. Doctors (n = 6) rated the severity of symptomatology of each case based only on medical details. There was no difference in the medical severity of the gastroenteritis episodes for hospital and home care groups. Instead families were most clearly differentiated using discriminant analysis by social variables; specifically hospital care families had poorer scores than home care families on social contact indices. This highlights the necessity for focusing on the wider social context in efforts at decreasing the incidence of childhood hospitalization.

Family↗
PubMed1991

Should children with minor medical problems be sent to hospital? A study of infant care practices within families.

The admission of children to hospital for minor medical problems is frequently influenced by family and social circumstances. This study compared the infant care practices of families of children admitted to hospital for gastroenteritis (n = 76) and families caring for children with gastroenteritis at home (n = 76). Mothers of children who were admitted to hospital were more likely to use medical sources of advice on parenting and less likely to use other non-family sources than home care mothers. They also received less support in the education/entertainment of their children from fathers. There were many similarities between the two groups, including the high level of behaviour problems of the children and the relatively low level of involvement of fathers in child care tasks. Both of these factors serve to increase stress on mothers to the point where they may be unable to cope with a sick child at home.

Chi-Square Distribution↗
PubMed1991

Cystic fibrosis in adolescents and adults.

A cystic fibrosis (CF) clinic for adults was established in 1977. We have reviewed the data on 164 patients who attended between 1977 and 1989. Twenty four patients had died, 11 being over 20 years after time of death. Of the 140 patients still alive, 61% were male and 53% were aged over 20 years. Only 55% were diagnosed by 1 year and 88% by 10 years. Almost all patients had respiratory symptoms and sputum culture yielded Pseudomonas species in 69%. Other respiratory problems included major haemoptysis and pneumothorax, each in 10%. We found a wide range of respiratory impairment among older patients. Among 3 patients aged over 23 years the mean (+/- S.D.) percent predicted FEV1 and FVC were 53.3% (+/- 18%) and 71.4% (+/- 20%) respectively. Mean weight in this group was 92.5% (+/- 14) of predicted. Malabsorption occurred in most patients and meconium ileus equivalent occurred in most patients and meconium ileus equivalent occurred in 34%. Other complications were clinical hepatomegaly (16%), diabetes mellitus (9%) and arthropathy (20%). Most patients were taking continuous antibiotics by mouth (89%) and by nebuliser (48%), beta-2 agonists by inhaler (57%) and oral steroids (29%). Almost all were taking multivitamins, pancreatic replacement therapy and multiple nutritional supplements. The number of CF "bed days" grew 12 fold since 1979 and the mean stay in hospital was double the hospital mean. The economic impact was such that over 1/4 of the annual hospital antibiotic budget was expended on CF patients.

Adolescent↗
PubMed1991

Occupational asthma.

Occupational asthma is becoming an increasingly common problem worldwide. To date however, the impact of this disorder in Ireland has not been evaluated. In this present study we document 39 cases of occupational asthma presenting to St. Vincent's Hospital between 1978 and 1988 and evaluate the patient characteristics, the occupationals involved, the causative agents and clinical course and outcome. The characteristics of the occupational asthma group were striking when compared to traditional occupational lung diseases, such as the pneumoconioses. These features were (i) the relatively young age--30 patients (77%) developed their disease by the age of 35, (ii) the presence of a substantial group of women--31% of the study group, and (iii) the relatively rapid onset of asthma after taking up employment--56% had asthma within three years of exposure. In contrast the pneumoconioses affect older, preponderantly male workers who manifest clinically symptomatic disease after decades of exposure. Long standing traditional industries were well represented ranging from milling and the bakery trade to textiles and printing. However, there was an even larger contribution from the more modern, high technology sector particularily the chemical, electronic and plastic industries.

Adult↗
PubMed1990

Collateral sprouting of the central terminals of cutaneous primary afferent neurons in the rat spinal cord: pattern, morphology, and influence of targets.

The capacity of the central terminals of primary afferents to sprout into denervated areas of neonatal spinal cord and the morphology of any novel terminals has been investigated. In rats which had undergone sciatic nerve section on the day of birth, 12 of 18 physiologically characterized intact saphenous hair follicle afferents (HFAs) were labelled intra-axonally with horseradish peroxidase (HRP) were shown to sprout up to 2,000 microns into the deafferented sciatic terminal field. The morphology of these sprouts depended on which area of the sciatic nerve territory was invaded by the afferent sprouts. Six HFAs sprouted into areas normally innervated by glabrous skin afferents and the morphology of the collateral sprouts in this region resembled that of rapidly adapting (RA) afferents. The other six saphenous HFAs had sprouted into sciatic "hairy" skin areas and the morphology of these sprouts, although abnormal, was flame shaped. In rats whose sural, saphenous, and superficial peroneal nerves were cut at birth, 4 of 7 single HRP labelled RA afferents had central terminals that had sprouted into regions of cord normally devoted to "hairy" input. These showed clear signs of HFA morphology despite their peripheral receptive fields remaining in the glabrous skin. The results show collateral sprouting of single cutaneous sensory afferent axons into adjacent inappropriate central target regions following neonatal deafferentation. Such plasticity may provide some compensation following neonatal injury. The morphology of the sprouted terminals is appropriate to the new target area rather than to its functional class and is also independent of the peripheral receptive field location providing an example of central rather than peripheral control over afferent growth patterns.

Afferent Pathways↗