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Biomedical subjects

L Owen

Publications and source records attributed to L Owen.

15 recordsLinked to original sources
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↗
PubMedDate not supplied

The pharmacokinetics in mice and dogs of nitroimidazole radiosensitizers and chemosensitizers more lipophilic than misonidazole.

We have examined the pharmacokinetic properties of nitroimidazole radiosensitizers and chemosensitizers more lipophilic than misonidazole (MISO). In dogs, 2 analogues showed comparable peak plasma concentrations with considerably shorter half-lives (t1/2) and reduced areas under curves (AUC). Benznidazole (Ro 07-1051) had a much longer t1/2, a higher AUC, and somewhat higher peak concentrations. In mice tumor/plasma, brain/plasma, and tumor/brain ratios were generally similar to MISO, as was penetration of brain and peripheral nerve by benznidazole in dogs. Selection of lipophilic analogues with appropriate pharmacokinetic properties may facilitate accommodation of the potentially different requirements for improved radiosensitization or chemosensitization.

Animals↗
PubMedDate not supplied

Swaddling and CDH.

Explore the source record for details and available documents.

Hip Dislocation, Congenital↗
PubMedDate not supplied

Adaptation of the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay for the determination of virus-neutralizing antibodies using the virus-neutralization assay.

The tetrazolium salt MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] has been widely used for bioassays. Herein is described the use of the MTT dye with a virus-neutralization (VN) assay to titer infectious bursal disease virus (IBDV)-neutralizing antibodies. A standard VN assay using chicken embryo fibroblasts (CEFs) and IBDV was used for the assessment of IBDV-neutralizing antibodies. The percent of CEF killing due to IBDV was quantitated using MTT, and the absorbance (A) data were used to calculate the VN antibody titer. This method of calculation offers the expression of VN titer in terms of units of activity per unit of volume.

Animals↗