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S C Allen

Publications and source records attributed to S C Allen.

At least 37 records · Page 2Linked to original sources
PubMed1994

A comparison of the predicted and X-ray structures of angiogenin. Implications for further studies of model building of homologous proteins.

The three-dimensional structure of human angiogenin has been determined by X-ray crystallography and is compared here with an earlier model which predicted its structure, based on the homology of angiogenin with bovine pancreatic ribonuclease A. Comparison of the predicted model and crystal structure shows that the active-site histidine residues and the core of the angiogenin molecule, including most of the beta-strands and alpha-helices, were predicted reasonably well. However, the structure of the surface loop regions and residues near the truncated C-terminus differs significantly. The C-terminal segment includes the active-site residues Asp-116, Gln-117, and Ser-118; Gln-117 in particular has been shown to be important in affecting the ribonucleolytic activity of angiogenin. Also, the orientation of one helix in the model differed from the orientation observed experimentally by about 20 degrees, resulting in a large displacement of this chain segment. The difficulty encountered in predicting the surface loop regions has led to a new algorithm [Palmer and Scheraga (1991), J. Comput. Chem., 12, 505-526; (1992), J. Comput. Chem., 13, 329-350] for predicting the conformations of surface loops.

Amino Acid Sequence↗
PubMed1991

Purification, characterisation and mutagenesis of highly expressed recombinant yeast pyruvate kinase.

Recombinant yeast pyruvate kinase has been purified from a strain of Saccharomyces cerevisiae expressing the enzyme to very high levels. Expression was from a multicopy plasmid under the control of the yeast phosphoglycerate kinase promoter. The gene was expressed in the absence of the genomically encoded pyruvate kinase, using a strain of yeast in which the pyruvate kinase gene has been disrupted by the insertion of the yeast Ura3 gene. The purification procedure minimised proteolytic artefacts and enabled the convenient purification of 15-20 mg enzyme from 11 culture. The purified enzyme was characterised by a high specific activity and by a lack of proteolytic degradation. Two active-site mutants of yeast pyruvate kinase have been produced, expressed and characterised in this system and preliminary results are described.

Chromatography, Gel↗
PubMed1990

Anorexia nervosa in the elderly: a case report and review of the literature.

Anorexia nervosa is a rare disorder in the elderly but should be thought of in the differential diagnosis of extreme weight loss, especially if there are accompanying psychological features and normal baseline investigations. Psychiatric opinion should be obtained and treatment, although of unproven value, considered, since improvement may increase mobility and reduce morbidity and mortality.

Aged↗
PubMed1989

The relation between height, armspan and forced expiratory volume in elderly women.

Loss of height occurs with ageing. This could distort the relation between height and forced expiratory volume in 1s (FEV1) as age increases. Armspan, which approximates to height at maturity, does not fall with age and might, therefore, be a better linear variable to compare with age and spirometric volumes in older people. We studied the relation between age, height, armspan and FEV1 in 150 women aged 60-91 years. The mean value of span minus height was 4.7 cm (range -5 to +17). Standardized FEV1 (SD) in 5-year age bands between 60 and 80+ fell as follows: 1.79(0.52)1, 1.62(0.49)1, 1.38(0.41)1, 1.32(0.44)1, 1.15(0.48)1. When re-standardized using armspan, the values were: 1.76(0.48)1, 1.59(0.53)1, 1.37(0.46)1, 1.29(0.47)1, 1.11(0.54)1. The differences between the two standardized values in each age band were not significant. It was concluded that span measurements offer no advantage over height measurements in cross-sectional population studies of lung volume in old age. However, in subjects who cannot have their height measured, or who are known to have lost a substantial amount of height, armspan is a reasonable substitute measure of body size from which to calculate predicted FEV1 values.

Aged↗
PubMed1989

Ambulatory electrocardiography in the elderly: an audit.

In a retrospective analysis of 264 episodes of ambulatory electrocardiography (AECG) in 252 elderly out-patients the overall diagnostic yield was only 12 per cent. However, AECG was found to be of significant value in detecting symptomatic tachyarrhythmias, and in confirming the diagnosis of the 'sick sinus syndrome'. The AECG results influenced the management plan in at least 16 per cent, and changes in drug treatment in 10 per cent. When interpreted critically, AECG is useful tool in the investigation of elderly patients with symptoms such as syncope, faintness, dizziness and unexplained falls.

Aged↗
PubMed1988

Clinical prognostic indices of fatality in elderly patients admitted to hospital with acute pneumonia.

Acute pneumonia in the elderly is a common and serious condition. The importance of key clinical features and physical signs presenting to the junior hospital doctor was prospectively assessed in 100 consecutive patients admitted acutely to two hospitals. The most significant finding is that elderly patients with pneumonia who are found to be acutely confused at the time of presentation or who gave a previous history of chronic brain failure are much more likely to die than others. Thus such patients should be assessed with particular attention to the early diagnosis and vigorous treatment of pneumonia.

Acute Disease↗
PubMed1986

What determines whether an elderly patient can use a metered dose inhaler correctly?

The metered dose inhaler (MDI) technique of 30 elderly patients (mean age 79.9 years) was assessed. Sixty per cent were competent, though only 10% had an ideal technique; 40% were incompetent. Inadequate timing of actuation and inhalation was the most frequent error made. Competence was significantly related to mental status questionnaire (MSQ) scores of 7/10 or more. Patients who were first prescribed an MDI in hospital were significantly more likely to be competent than those prescribed an MDI by the general practitioner. Competence was not related to age, underlying diagnosis or duration of MDI therapy. Elderly patients requiring MDI therapy should be carefully selected and properly instructed by the prescribing doctor.

Aerosols↗
PubMed1986

Osteoid osteoma in a cervical pedicle. Resection via transpillar approach.

Lesions in the pedicles of the cervical spine are both a diagnostic and technical challenge. An osteoid osteoma of the pedicle of the fourth cervical vertebra occurred in a 17-year-old girl. Resection of the tumor adjacent to the dura medially and the vertebral artery anterolaterally was accomplished via a transpillar approach. The transosseus approach preserved the facet joints and posterior elements and obviated the need for an interbody fusion.

Adolescent↗
PubMed1984

Lobar pneumonia in Northern Zambia: clinical study of 502 adult patients.

From July 1981 to January 1983 502 adults were treated for lobar or segmental pneumonia in a general hospital in Northern Zambia. Consolidation was present in either the right or the left lower lobe in 78.8%, the right middle lobe in 10.2% and either the right or the left upper lobe in 10.7%. Penicillin treatment failed to give an improvement in 10.7%, many of whom recovered after receiving either gentamicin or kanamycin. A high risk of death was associated with an age of 65 years or over, absence of pyrexia, absence of a leucocyte response, disease affecting multiple lobes, irreversible hypotension, underlying neoplasm, and failure to respond to penicillin treatment (p less than 0.001 in all cases). Penicillin remains the initial treatment of choice for lobar pneumonia in rural central Africa. Mortality can probably be reduced by inpatient treatment of as many patients with pneumonia as local circumstances allow, and by adding broad spectrum treatment in patients who show no improvement after 48 hours of penicillin treatment.

Adolescent↗
PubMed1983

Comparison of nebulized salbutamol with nebulized ipratropium bromide in acute asthma.

Twelve patients admitted to hospital with an acute attack of bronchial asthma were studied. Six were treated initially with nebulized salbutamol solution by inhalation and 1 hour later by ipratropium bromide given in the same way; the other six were treated first with ipratropium bromide and 1 hour later by salbutamol. Ipratropium bromide was shown to be as effective as salbutamol when used as the initial bronchodilator but salbutamol produced significant further improvement when given 1 hour after ipratropium.

Acute Disease↗
PubMed1983

Dose-response comparison of ipratropium bromide from a metered-dose inhaler and by jet nebulisation.

The dose-response relationships of the anticholinergic bronchodilator drug ipratropium bromide were studied. Cumulative doses totalling 288 micrograms ipratropium were given by inhalation of a liquid aerosol from a Wright nebuliser to each of 10 patients with stable, moderately severe airflow obstruction. Up to 80% of the maximum achievable bronchodilator response, as assessed by a rise in the patients' mean forced expiratory volume in one second (FEV1), was obtained with a cumulative total dose of 72 micrograms; with additional doses beyond 72 micrograms there was no significant further improvement. In the same patients the effects of administration of cumulative doses of ipratropium to a total of 72 micrograms from a Wright nebuliser were compared with those achieved with a metered-dose inhaler. Bronchodilatation was assessed by measurement of peak expiratory flow rate, FEV1, forced vital capacity, thoracic gas volume and specific airways conductance (sGaw). No significant difference was observed in the response at any dose level between the wet and the dry aerosols. By fitting a curve to the mean values of FEV1 and sGaw an estimate was made of the dose of ipratropium bromide required to produce 99% of the achievable bronchodilator response. For FEV1 this dose was 78 micrograms when ipratropium was inhaled as a nebulised solution from the Wright nebuliser and 82 micrograms when it was inhaled from the metered-dose inhaler; for sGaw the respective values were 54 and 58 micrograms. In these patients with stable airflow obstruction there was no therapeutic advantage in the use of ipratropium bromide as a wet aerosol.

Adult↗