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Biomedical subjects

L Owen

Publications and source records attributed to L Owen.

At least 37 records · Page 2Linked to original sources
PubMed1997

Rare earth elements as nonabsorbable fecal markers in studies of iron absorption.

The use of rare earth elements as nonabsorbable fecal markers for studies of iron absorption from sources labeled extrinsically with stable isotopes was evaluated. On 3 successive days 13 healthy fasting adults were given different stable isotopes of iron with samarium, ytterbium, or dysprosium. On day 1, three meals were given with 57Fe (1 mg per meal) plus samarium (0.33 mg per meal); on day 2, identical meals (taken with a calcium supplement to reduce iron bioavailability) were given with equivalent amounts of 58Fe-labeled iron and ytterbium; on day 3, a well-absorbed reference dose of 54Fe (3 mg) was given with 1 mg Dy. A complete fecal collection was carried out for 5-9 d and each stool was analyzed for rare earth elements by inductively coupled plasma-mass spectrometry and iron isotopes by thermal ionization quadrupole mass spectrometry. Mean recovery of rare earth elements was 101%, indicating that they are totally unabsorbed. The excretory pattern of the iron isotopes and the rare earth elements was very similar; the correlation coefficients between samarium and 57Fe, ytterbium and 58Fe, and dysprosium and 54Fe were 0.992, 0.989, and 0.988, respectively (P < 0.001). Iron absorption was calculated as the difference between isotope dose and fecal excretion. Mean (+/-SEM) iron absorption was 16.7 +/- 2.4%, 4.3 +/- 1.6%, and 40.3 +/- 3.1% on days 1-3, respectively. Predicted values estimated from the first 4 d of pooled feces, using the rare earth element recovery data to produce corrected figures for unabsorbed isotope, were in close agreement: 19.1 +/- 2.1%, 4.6 +/- 1.7%, and 40.8 +/- 3.1%, respectively (P < 0.001). With the diet of medium iron bioavailability and with the highly bioavailable reference dose it was possible to predict iron absorption accurately from only one or two stools, provided that they were sufficiently enriched with isotope and a rare earth element.

Absorption↗
PubMed1997

The named nurse: patient and nurse expectations.

The named nurse concept was introduced to provide patients with one nurse responsible for their care during a hospital stay. Research into patient and nurse expectations of the role is needed if the named nurse concept is to be evaluated.

Attitude of Health Personnel↗
PubMed1995

Value from resources in Southampton University Hospitals NHS Trust.

Outlines the use of the "value from resources" approach to build bridges between clinicians and managers. The simple but powerful use of graphical interactive presentations has resulted in increased staff awareness of how quality improvement and resource utilization are inextricably linked.

Health Resources↗
PubMed1994

Evaluation of a mass media campaign on smoking and pregnancy.

Two surveys were conducted among pregnant women throughout England, before (n = 625) and after (n = 607) a mass media campaign on smoking and pregnancy targeted at women aged 15-24 years, in the social grade C2DE. The majority of the post-campaign sample recalled having seen at least one of the campaign's series of press advertisements. There was a significant increase among this sample in those considering smoking to be very dangerous to the unborn child, in those understanding the term passive smoking and in those considering passive smoking to be very dangerous. During the campaign there was a 14% increase in the number of calls to a cessation helpline from pregnant women. Over the campaign there were no significant changes in smoking prevalence and consumption among pregnant women or partners or in the numbers of partners offering suggestions to pregnant women about their smoking behaviour.

Adolescent↗
PubMed1989

Profiles of instant heart rate during partial seizures.

Instant heart rate (R-R intervals) can be readily studied during spontaneous seizures recorded with ambulatory cassette AEEG/AECG techniques. Ninety-three seizures were recorded in 32 patients with complex partial epilepsy. Instant R-R interval plots showed that 74% of seizures were associated with a dominant tachycardia, the most characteristic features of which were the initial steep acceleration phase at seizure onset and the wide fluctuations in heart rate ('exaggerated sinus arrhythmia') which occurred during and immediately after the seizure. Five percent of seizures were associated with a dominant but transient phase of heart rate slowing during or towards the end of the seizure. Nineteen percent of seizures showed equivocal or negative ictal effects on the heart rate and rhythm despite unequivocal AEEG seizure discharges. Conversely, other patients had characteristic heart rate changes despite equivocal AEEG abnormality. The heart rate profiles showed striking seizure-to-seizure similarities when multiple fits were recorded in the same patient. Ratemeter profiles may be clinically useful to locate epileptic seizures in long duration records; they can help to locate seizures which are either inaccurately timed or poorly identified by the event marker, or not clearly associated with definite AEEG changes. The secondary cardiac effects of epilepsy may be misdiagnosed if their primary cerebral origin is not suspected.

Adult↗
PubMed1989

Pseudostatus epilepticus.

Thirteen patients with pseudostatus (simulated status epilepticus) have been compared to 13 patients with true status epilepticus seen at a regional neurological centre. Pseudostatus was common in patients with pseudoseizures and was often misdiagnosed as status epilepticus. Complications of this misdiagnosis included eight episodes of anticonvulsant-induced respiratory arrest. Patients with pseudostatus commonly had multiple episodes of 'status'. They usually also had a history of other unexplained illness and of deliberate self-poisoning. Management of these patients was difficult and emphasizes the need for specialist expertise for patients with epilepsy and apparent epilepsy.

Adolescent↗
PubMed1986

Electrocardiographic accompaniments of temporal lobe epileptic seizures.

74 spontaneous seizures in 26 patients with a clinical diagnosis of temporal lobe epilepsy (complex partial seizures) were recorded by simultaneous ambulatory cassette monitoring of the electrocardiogram and the electroencephalogram (EEG). In 24 patients (92%) seizures were associated with an increased heart rate. The maximum heart rates exceeded 120 beats/min in 67% of seizures, 140 beats/min in 30%, and 160 beats/min in 12%. The acceleration of heart rate was greater in patients under than in those over 25 years old (p less than 0.01) and in those not treated with than in those on anticonvulsant drugs (p less than 0.01). Ictal cardiac arrhythmias occurred in 42% of the patients and the commonest was an irregular series of abrupt rate changes which occurred towards the end of the EEG seizure discharge. Asymptomatic (clinically silent) arrhythmias occurred no more frequently in the patients than in age and sex matched healthy subjects. These secondary autonomic effects of epilepsy may lead to diagnostic errors if their cerebral origins are not suspected. They seem to be reduced in severity by anticonvulsant drugs (ACD) and they may account for sudden unexplained deaths in epileptics.

Adolescent↗
PubMed1986

The significance of the adrenergic nerves in the etiology of vesicoureteral reflux.

We studied 40 puppies serially from birth to 6 months of age for the presence of vesicoureteral reflux. Of these dogs 36 underwent biopsy of the bladder dome and trigone in search of adrenergic fibers that could be identified by catecholamine fluorescence. The results show that the incidence of vesicoureteral reflux decreased dramatically as adrenergic fibers began to appear. This inverse relationship between reflux and adrenergic bladder fibers seems to suggest a cause-and-effect relationship.

Adrenergic Fibers↗
PubMed1986

Uptake and transepithelial transport of nerve growth factor in suckling rat ileum.

Nerve growth factor (NGF) is necessary for the development of sympathetic and some sensory neurons. Milk may be a source of NGF for suckling young, but sites of intestinal absorption of the protein have not been identified. To determine whether NGF is transported across the absorptive epithelium of suckling rat ileum, we assessed binding, uptake, and transport of 125I-NGF by light microscopy and EM autoradiography. Blood and tissue extracts were analyzed by biochemical and immunological methods to determine whether NGF was taken up structurally intact. NGF binding sites were identified on microvilli and apical invaginations of ileal absorptive cells in vitro. Injected into ileal loops in vivo, NGF radioactivity retained by fixation was evident after 20 min in apical regions of absorptive cells, in endocytic tubules (which mediate the uptake of membrane-bound ligands), in vesicles (which mediate nonspecific endocytosis), and in the supranuclear lysosomal vacuole. At 1 and 2 h, radiolabel in these compartments increased and silver grains were evident at the basal cell surface, and in cells, matrix, and vessels of the lamina propria. In blood and liver, radiolabeled molecules that were immunologically and electrophoretically indistinguishable from NGF and that co-eluted with NGF on gel filtration columns were detected, confirming that some NGF was transported across the epithelium structurally intact. Thus, absorptive cells of suckling rat ileum can take up NGF by both receptor-mediated and nonspecific endocytosis, and direct NGF either to the lysosome for degradation, or into a transepithelial transport pathway.

Animals↗