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Biomedical subjects

D Fagan

Publications and source records attributed to D Fagan.

At least 19 recordsLinked to original sources
PubMed1998

Child abuse and neglect: the knowledge and practice of the A & E nurse.

The recognition of child abuse depends greatly on the skills of the Accident and Emergency (A & E) nurse. A lot of what is written in the relevant literature is repetitive. Much is written about what A & E nurses should know and should do, but there appears to be no research which examines their actual skills and knowledge in this area. This article addresses this and by using a Constructivist approach for the inquiry, identifies what a group of A & E nurses know about child abuse and what they do when a possible victim presents to the department. It identifies some cases which need addressing, particularly knowledge of current policies, guidelines and legislation. Also identified are the skills A & E nurses possess and those they utilize. The paper concludes that further training and education is needed for multidisciplinary decision making about the role of the A & E nurse within the context of child abuse and neglect.

Attitude of Health Personnel↗
PubMed1998

Analysis of birthweight and gestational age in antepartum stillbirths.

OBJECTIVE: To study the characteristics of birthweight and gestational age of third trimester fetal deaths which occurred before the onset of labour. DESIGN: Review of computerised confidential perinatal mortality records. Data originated from the 1992 Trent Region Perinatal Mortality Survey. SAMPLE: One hundred and forty-nine antepartum stillbirths of at least 24 weeks of gestation confirmed by early ultrasound scan. Congenital abnormalities and multiple pregnancies were excluded. MAIN OUTCOME MEASURES: Reported causes of stillbirth; weight-for-gestational age centiles based on a standard derived from normal pregnancies; pregnancy characteristics compared with the local maternity population. RESULTS: Of 149 stillbirths, 83 (56%) were preterm and 66 were at term, and the majority (126; 85%) occurred from 31 weeks. Most of the deaths (97; 65%) were reported as 'unexplained' even though post-mortems had been carried out in 60% of all cases. Using a gestational age-specific fetal weight standard derived from normal, term live births, 41% of all cases of stillborn infants were small-for-gestational age (< 10th centile; OR 6.2; 95% CI 3.3-11.5); 39% of which had been classified as unexplained were small for gestational age (OR 5.6; 2.6-12.0). This excess of small stillbirths was most pronounced between 31 and 33 weeks, where the weights of 63% of all stillbirths and 72% of unexplained fetal deaths were < 10th centile. Overall, a higher proportion of preterm (< 37 weeks) than term stillbirths were small for gestational age: 53% vs 26% (OR 3.3; 1.6-6.5). However, at term there were also more subtle differences in weight deficit, with more fetuses with a weight between the 10th and 50th centiles than between 50th and 90th (36 vs 11; OR 3.3; 1.4-7.8). Mothers of pregnancies ending in stillbirth were similar in age, size, parity and ethnic group to mothers of live born babies, but were more likely to be smokers (37 vs 27%, OR 1.6; 1.2-2.3). CONCLUSIONS: Many stillborn babies are small for gestational age. In the absence of significant differences in physiological pregnancy characteristics, this is unlikely to be a constitutional smallness, but represents a preponderance of intrauterine growth restriction. For a full appreciation of the strength of this association, appropriate weight standards and classifications need to be applied in perinatal mortality surveys. Many antepartum stillbirths which are currently designated as unexplained may be avoidable if slow fetal growth could be recognised as a warning sign.

Birth Weight↗
PubMed1996

Innervation of human atrioventricular and arterial valves.

BACKGROUND: Limited information exists on the innervation of human cardiac valves and the relationship of nerve fibers and terminals with functional elements within leaflets. METHODS AND RESULTS: We examined human AV and arterial valves, obtained postmortem and at surgery, using quantitative immunohistochemical, histochemical, and confocal microscopic techniques. Significant differences in nerve density and distribution were found both between and within cardiac valves. Nerve density within the anterior leaflet of the mitral valve, for example, was twofold greater than that in the posterior leaflet (P < .001). Nerves within the AV valves were situated in the atrial layer and extended over the proximal and medial portions of the leaflets, whereas those in the arterial valves were situated in the ventricular layer. No nerves reached either the free edge or the fibrous core of the leaflets. The arterial valves displayed a similar density of innervation, except for the noncoronary leaflet of the aortic valve in which the innervation was attenuated (P < .01). The innervation of aortic valvar leaflets was age dependent. Nerve terminal arborizations, arising from myelinated nerves and exhibiting variable morphology, were detected in all four cardiac valves and in some tendinous cords. Nerve terminals exhibited either acetylcholinesterase activity or tyrosine hydroxylase and neuropeptide Y immunoreactivity. Varicose nerve fibers occurred in close physical proximity to valvar endothelial, smooth muscle, and fibroblast cells. CONCLUSIONS: Human cardiac valves have distinct patterns of innervation that comprise both primary sensory and autonomic components. The presence of distinct nerve terminals and the close association of varicose nerve fibers with endothelial, smooth muscle, and fibroblast cells suggest a possible neural involvement in the control of valvar function.

Acetylcholinesterase↗
PubMed1995

Distribution, morphology, and neurochemistry of endocardial and epicardial nerve terminal arborizations in the human heart.

BACKGROUND: The heart contains a variety of morphologically distinct nerve terminals known to influence cardiac function. Little is known about the distribution, morphology, and neurochemistry of these terminals in the human heart. METHODS AND RESULTS: We examined the entire endocardial and epicardial surfaces of infant and adult hearts obtained postmortem and at transplantation using immunohistochemical and histochemical staining of whole-mount preparations in conjunction with confocal and fluorescence microscopy. Terminals arising from nerve fibers (diameter, 6 to 10 microns) immunoreactive for myelin basic protein were identified in the atrial endocardium, epicardium, and coronary sinus, and four types were distinguished by differences in immunostained nerve area (range, 358 to 797 microns 2) and dispersion (range, 620 to 4684 microns 2). These terminals displayed immunoreactivity for tyrosine hydroxylase, neuropeptide Y, and the general neural marker protein gene product 9.5. Acetylcholinesterase (AChE) activity was detected in < 5% of endocardial terminals and in no epicardial terminals arising from myelinated fibers. The latter were observed in close proximity to mesothelial cells, and nerve fibers supplying these terminals were found to be associated with local ganglia. A distinct population of terminals (mean stained area, 35 microns 2; 18 to 53 microns 2, 95% CI; and mean dispersion, 59 microns 2; 38 to 80 microns 2, 95% CI) was demonstrated to arise from nonmyelinated fibers (mean diameter, 2.5 microns; 2.2 to 2.8 microns, 95% CI) in the endocardial plexus of the atria and left ventricle and were predominantly AChE-positive. CONCLUSIONS: Specialized nerve terminals are distributed more widely in the human heart than has been described in experimental animals. These terminals express either AChE activity or tyrosine hydroxylase and neuropeptide Y immunoreactivity, suggesting that acetylcholine, catecholamines, and neuropeptide Y may be present in sensory and autonomic nerves in the human heart.

Acetylcholinesterase↗
PubMed1995

Factors associated with noncompliance of patients taking antihypertensive medications.

Poor adherence to drug therapy decreases the effectiveness of antihypertensive treatment. Patients must take more than 80% of their antihypertensive drugs to maintain adequate blood pressure control. To understand the incidence of noncompliance and contributing factors, a pilot study was conducted in which a questionnaire was devised and administered to a random sample of 243 hypertensive patients of the adult ambulatory care clinic at Methodist Hospital of Indiana. Ninety-eight patients completed the telephone survey. Demographic data were obtained through chart reviews. The results indicated that 30-46% of the patients were noncompliant with their antihypertensive drug regimens. Factors found to be associated with noncompliance were; employment (P = .0077), use of home remedies (P = .0043), age (P = .0165), experience of side effects (P = .0051), level of concern with missed doses (P = .0043), and cost (P = .014). The incidence of noncompliance in this pilot sample is lower than the estimated 50% noncompliance rate of published data. More research is needed to understand the determinants of noncompliance in order to design interventions to improve compliance.

Adult↗
PubMed1994

A dose-response study of the effects of inhaled nitrous oxide on psychological performance and mood.

In this five-period randomised double-blind crossover study, 12 healthy volunteers inhaled mixtures of nitrous oxide at concentrations of 0% (placebo); 5%, 10%; 20% and 40% in oxygen. Each concentration was inhaled for about 1 h, each period being on a separate day. The effects of nitrous oxide were measured using a comprehensive battery of performance tests including measures of attention, psychomotor function, memory and cognition. Mood was assessed with visual analogue scales. All tests except critical flicker fusion showed substantial effects at the highest does (40%). No measure showed evidence of change at the lowest concentration (5%). Several measures showed significant impairment at 10%, viz: digit-symbol substitution, choice reaction time (latency and total), tapping, and continuous attention. Subjects felt dizzy and muzzy on nitrous oxide, but no significant effect was seen on the Alert-Drowsy VAS. The dose-response profiles of the various tests showed substantial differences. Thus tapping was virtually linear, while choice reaction motor time and body sway showed steeply accelerating impairment with increasing dose. These results indicate that comparisons of profiles of drug-induced change must take into account the variable effects of dose before interpretations in terms of specific drug effects can be made.

Administration, Inhalation↗
PubMed1994

Inhalation anaesthetic competition at high-affinity cocaine binding sites in rat brain synaptosomes.

We have shown previously that inhalation anaesthetics inhibit dopamine transport in rat synaptosomes. In order to determine if this inhibition is associated with occupancy of the cocaine site, we examined binding of [3H] (2 beta-carbomethoxy-3 beta-(4-fluorophenyl)-tropane) (3H-CFT) in the presence of halothane or isoflurane 0.01-5 mmol litre-1 in rat brain synaptosomes. Both anaesthetics inhibited 3H-CFT binding (mean Ki 0.61 (SEM 0.12) and 0.75 (0.21) mmol litre-1, respectively), by increasing Kd (13.8 (0.6) and 29.8 (12.8) nmol litre-1, respectively) compared with control (8.02 (0.5) nmol litre-1) (P < 0.01). Halothane did not change Bmax, but isoflurane increased it significantly. Cocaine protected CFT sites from N-ethylmaleimide alkylation, but neither anaesthetic did. Photoaffinity labelling with halothane significantly inhibited 3H-CFT binding compared with UV-exposed controls. We conclude that clinically relevant concentrations of both anaesthetics inhibit high-affinity CFT binding, and the data suggest overlapping sites for halothane and CFT.

Anesthesia, Inhalation↗
PubMed1992

The de-endothelialized rat carotid arterial graft: a versatile experimental model for the investigation of arterial thrombosis.

A novel model of arterial thrombosis was developed. A mechanical endothelium-denuding injury was created (using a scalpel blade) on harvested, freezer-stored rat carotid arteries. Vessel length of 5 mm. were grafted into the femoral arteries of recipient Sprague-Dawley rats using microvascular anastomotic technique. Patency rates in untreated animals were compared with those in animals receiving systemic aspirin or heparin. The control group patency after 2 hours of flow was 15%, while grafts in aspirin- and heparin-treated animals achieved 35% and 95% patency rates, respectively. Uninjured non-frozen carotid grafts in untreated animals yielded a 95% patency rate, while frozen grafts achieved an 80% patency. Therapeutic levels of aspirin, heparin, and urokinase were confirmed through tail bleeding and whole blood clotting tests, as well as platelet aggregation studies and scanning electron microscopy of the graft lumenal surfaces. A long-term series using syngeneic grafts placed in recipients (Lewis-to-Lewis) and employing systemic heparinization demonstrated maintenance of patency for 4 weeks. Scanning electron microscopy revealed good re-endothelialization, well advanced by one week. Histology confirmed the regrowth of endothelial cells, but showed sparse cellular repopulation of medial and adventitial layers. The mechanical injury model was compared to enzymatic de-endothelialization (using trypsin or collagenase), for which patency rates were similar (10% and 0%, respectively). Trypsin de-endothelialized vessels were tested in vitro for the amount of active trypsin remaining bound to the lumenal surface; no detectable activity was found when trypsin inhibitor was applied following trypsin treatment. The versatility of allowing both in vitro evaluation and in vivo patency assessment demonstrates the uniqueness and value of this new model, offering an avenue toward more direct investigations of surface-mediated thrombotic processes.

Anastomosis, Surgical↗
PubMed1991

Effects of remoxipride on measures of psychological performance in healthy volunteers.

The acute psychomotor effects after oral doses of 30, 60 and 120 mg remoxipride, a new selective D2 receptor blocker, and placebo were investigated in a double-blind crossover study in 11 healthy male volunteers. Two out of the first three subjects given 120 mg remoxipride experienced marked akathisia, and therefore no subsequent subjects were given this dose. There were no other clearly drug-related adverse effects reported below 120 mg, although restlessness was reported at 60 mg. Remoxipride was associated with increases in error scores on a continuous attention task and on auditory vigilance, and with a reduction in critical flicker frequency, suggesting a decrease in arousal level. There were no significant changes in psychomotor measures such as choice reaction time, decision making time, or body sway. Subjective assessments using visual analogue scales showed a slight dose-related increase in drowsiness, while the calm-excited scale showed a small change in the excited direction with 30 mg only. The peak effects were at 4-6 h after drug intake, which was later than expected from previous pharmacokinetic data. These results indicate that remoxipride may have a slight depressant effect in the dose-range used. The pattern of changes is consistent with current theories on the role of dopamine in attention and arousal, and with the effects of other neuroleptics. It differs, however, from tranquilisers such as the benzodiazepines, which show a more global pattern of effects.

Adult↗
PubMed1991

Medical Facts File: a self service database of reference information.

The Dahlgren Memorial Library, Georgetown University Medical Center, will demonstrate Medical Facts File, a newly developed in-house database of general medical information. The file content emerged from the library's experience with commonly asked reference questions and the need to develop a database as an online source for users seeking quick answers to medical queries. Medical Facts File joins a growing family of over 18 databases which comprise Georgetown's IAIMS Knowledge Network. Use scenarios will demonstrate how an online search is initiated, either directly or as a prompt from one of the other online databases. The design of Medical Facts File at the Dahlgren Memorial Library began in late 1989 with a publishing section on instructions for authors planning to submit manuscripts to a variety of prominent medical journals. Since then, seven sections have been identified for the database. Three sections are highlighted for presentation, although work on the project is on-going. Medical Facts File is an easy-to-use, time saving system that facilitates tedious searching through a multitude of library sources. It provides users with a self-service, information look-up system.

Databases, Factual↗
PubMed1990

A study of the psychometric effects of chlormethiazole in healthy young and elderly subjects.

The pharmacokinetics and effects of chlormethiazole (91 mg intravenously together with 356 mg orally) on psychomotor performance were studied in 10 young (mean age 29 years) and 10 older (mean age 66.2 years) volunteers using an open design. Chlormethiazole affected psychomotor function and decreased subjective arousal in both age groups. The peak effect was found at approximately 30 min, i.e. at the end of the infusion, and performance returned to normal by 3 h. There was no evidence of increased sensitivity of the older subjects to the psychomotor or subjective effects of chlormethiazole. The incidence and type of reported symptoms was also similar in the two age groups. The volume of distribution of chlormethiazole was greater in the old than in the young subjects as was the elimination half-life after intravenous administration. Other pharmacokinetic variables showed no significant differences between young and old subjects.

Administration, Oral↗
PubMed1990

A comparison of the CNS effects of enprofylline and theophylline in healthy subjects assessed by performance testing and subjective measures.

1. The effects of intravenous infusions of enprofylline, theophylline, and placebo on subjective ratings and on psychological test performance were studied in a double-blind crossover experiment in 12 healthy subjects who abstained from caffeine throughout the experimental procedures. 2. Mean plasma concentrations of enprofylline were: mean 2.9 mg l-1 (range 1.9-3.4). Those for theophylline were: mean 12.1 mg l-1 (range 9.0-14.4). 3. Performance on the auditory vigilance task showed a significant improvement with theophylline compared with both enprofylline and placebo. The correct detection rates (out of 90) were 50.3, 43.4 and 39.1 respectively. A similar effect was seen with finger tapping rates: 404, 394 and 390 taps min-1 respectively. Other measures showed no significant effects, although choice reaction time showed a trend towards faster responses with theophylline. 4. Subjective ratings showed that subjects were significantly more alert with theophylline than with enprofylline. Subjects reported themselves as significantly more dizzy and ill with both active drugs compared with placebo. 5. These results suggest that emprofylline largely lacks the CNS stimulant effects of theophylline, but that the incidence of other unwanted effects of the drugs may be similar.

Acoustic Stimulation↗
PubMed1989

The cell biology of fibroblast cyclooxygenase.

We have prepared polyclonal antisera against sheep seminal vesicles cyclooxygenase (COX) which cross-reacted with human COX. We employed this antisera in studies with human dermal fibroblast cultures to immunoprecipitate selectively the COX enzyme. Labeling of the cells with [35S]-methionine, solubilization of cellular COX followed by its immunoprecipitation, SDS-PAGE electrophoresis and fluorography enabled us to determine directly the synthetic rate of COX protein and its modulation by the monokine interleukin-1 (IL-1). The immunoprecipitated [35S]-labeled COX, as judged from SDS-PAGE electrophoresis, has a molecular size of approximately 73,000 daltons, similar to that of native sheep COX and [3H]-acetyl COX. IL-1 stimulation of enhanced COX synthesis was time and dose dependent; as little as 0.03 units/ml of IL-1 produced significant stimulation of [35S]-labeled COX synthesis. Maximum stimulation was 3-10-fold after preincubation of the cells with IL-1 for 12-16 hours. IL-1 treatment of cells in serum-free media yielded parallel dose response curves for stimulation of PGE2 formation, cellular solubilized COX activity and synthesis of newly formed COX, suggesting that this IL-1 effect is mediated solely via induction of new COX protein synthesis. In contrast, IL-1 effect on cells incubated in the presence of fetal calf serum is more complex. Serum synergistically augments the IL-1 effect on PGE2 synthesis in intact cells but concurrently blunts IL-1 induction of COX synthesis, thus suggesting that a factor (or factors) in serum may stimulate PGE2 production by activating cellular phospholipase(s).

Animals↗
PubMed1989

Disposition kinetics of ropivacaine in humans.

The pharmacokinetic characteristics of a new local anesthetic drug, ropivacaine, were determined after intravenous infusion of 50 mg of the hydrochloride salt into six healthy male volunteers. Results showed that the disposition of ropivacaine can be described by a biexponential function. Its blood clearance (0.72 +/- 0.16 L/min) is intermediate between that of mepivacaine and bupivacaine. Plasma binding averaged 94% +/- 1% and the volume of distribution at steady state based on blood drug concentration was 59 +/- 7 L. The terminal elimination half-life was 111 +/- 62 min.

Adult↗
PubMed1989

Acute toxicity of ropivacaine compared with that of bupivacaine.

The acute central nervous and cardiovascular effects of the local anesthetics ropivacaine and bupivacaine were compared in 12 volunteers in a randomized double-blind manner with use of intravenous infusions at a rate of 10 mg/min up to a maximal dose of 150 mg. The volunteers were all healthy men. They were familiarized with the central nervous system (CNS) toxic effects of local anesthetics by receiving a preliminary intravenous injection of lidocaine. The infusions of ropivacaine and bupivacaine were given not less than 7 days apart. CNS toxicity was identified by the CNS symptoms and the volunteers were told to request that the infusion be stopped when they felt definite but not severe symptoms of toxicity such as numbness of the mouth, lightheadedness, and tinnitus. In the absence of definite symptoms, the infusion was stopped after 150 mg had been given. Cardiovascular system (CVS) changes in conductivity and myocardial contractility were monitored using an interpretive electrocardiograph (which measured PR interval, QRS duration, and QT interval corrected for heart rate) and echocardiography (which measured left ventricular dimensions from which stroke volume and ejection fraction were calculated). Ropivacaine caused less CNS symptoms and was at least 25% less toxic than bupivacaine in regard to the dose tolerated. Both drugs increased heart rate and arterial pressure. Stroke volume and ejection fraction were reduced. There was no change in cardiac output. Although both drugs caused evidence of depression of conductivity and contractility, these appeared at lower dosage and lower plasma concentrations with bupivacaine than with ropivacaine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Isolation and characterization of the complementary DNA for sheep seminal vesicle prostaglandin endoperoxide synthase (cyclooxygenase).

An oligonucleotide probe was used to isolate a clone encoding prostaglandin endoperoxide synthetase (cyclooxygenase, EC 1.14.99.1) from a sheep seminal vesicle cDNA library. The protein predicted from nucleic acid sequence contains 599 amino acids including a 23-amino acid signal sequence. Thus, the mature cyclooxygenase deduced from the cDNA compares favorably in molecular size to the 70-kDa protein determined by gel electrophoresis. A putative transmembrane region and potential carbohydrate addition sites for N-linked sugars can be inferred from the amino acid sequence. Significantly, sequence similarities exist between cyclooxygenase, myeloperoxidase, and several other heme-containing proteins. The putative glycosylation sites, transmembrane domain, and sequence similarities with functionally related enzymes have been incorporated into a model for the topology of cyclooxygenase in the endoplasmic reticulum.

Amino Acid Sequence↗