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Biomedical subjects

A Miller

Publications and source records attributed to A Miller.

At least 505 records · Page 28Linked to original sources
PubMed1985

The structure of collagen.

A knowledge of the structure of collagen fibrils is important for any rational discussion of the occurrence and treatment of fibrosis. The different genetic types of collagen, and the structure of the triple-helical molecule as refined from X-ray fibre diffraction data, are described. The problem of determining molecular arrangement in native tissues is discussed. The various models proposed for the molecular arrangement of type I collagen are compared and an account is given of the quasi-hexagonal model. A detailed analysis of the X-ray diffraction patterns from native type I collagen fibres is used to provide a quantitative description of the quasi-hexagonal model. Parameters such as molecular positions, azimuthal orientation and axial shift can be estimated from the diffraction patterns. These parameters refer to the helix main-chain. Side-chain conformations can then be built in by molecular graphics and the predicted X-ray pattern for the complete model compared with the observed pattern.

Animals↗
PubMed1985

Ro 31-1118, a new cardioselective beta-adrenoceptor antagonist. Pharmacokinetics and effects on heart rate and blood pressure in mild hypertensives.

Five patients with mild hypertension were given single oral doses of Ro 31-1118 (10,20,40, and 80 mg) and placebo in a randomized, double-blind, within-patient study. Plasma concentrations of Ro 31-1118 and supine, standing, exercise, and post-exercise heart rates and blood pressures were measured before and at regular intervals after drug administration. The pharmacokinetic data were consistent with a one-compartment model with first-order absorption and a variable time lag. Peak plasma concentrations and area under curve were linearly related to dose, whereas time to peak concentration, half-time, clearance and apparent volume of distribution were dose-independent. There was a reduction in exercise and post-exercise heart rate of approximately 10% after 10 mg and 20 mg Ro 31-1118, and of approximately 15% after 40 mg and 80 mg. At all doses standing systolic blood pressure was reduced by approximately 5%. A similar fall was seen in exercise and post-exercise systolic blood pressures. There was no substantial effect of Ro 31-1118 on supine or standing heart rates nor on diastolic blood pressure. No adverse effects were reported. It is concluded that Ro 31-1118 has linear pharmacokinetics over the dose range 10-80 mg, and has a weak antihypertensive effect when administered in single doses to patients with mild hypertension.

Absorption↗
PubMed1985

External beam pelvic radiotherapy plus intraperitoneal radioactive chronic phosphate in early stage ovarian cancer: a toxic combination. A National Cancer Institute of Canada Clinical Trials Group Report.

As part of a randomized trial evaluating several treatment programs in the management of poor prognosis, early stage ovarian cancer, 53 patients were randomized to receive a combination of pelvic external beam radiation, 4000 rad plus 10-20 millicuries of radioactive chromic phosphate given intraperitoneally. Only 35 patients (66%) actually received the chromic phosphate. The other 18 did not enter this phase of treatment for a variety of reasons documented in this report. Ten (29%) of the 35 patients receiving the full course of treatment had significant long term side effects with the median time to onset of symptom being 9 months after the chronic phosphate was given. There were no treatment-related deaths. The complications could not be related to the dose of the isotope, the technique of administration, nor any other definable predisposing factors. This combination is not recommended for further study.

Brachytherapy↗
PubMed1985

A study of the dependency of elderly patients in wards using different methods of nursing care.

Geriatric wards using individualized care (nursing process) were compared with task allocation wards in three hospitals. Patient dependency was measured using the CAPE scales. Patients admitted to the wards were similar in dependency but patients who had been in hospital for more than a month were significantly less dependent if they had been cared for in individualized care wards. Patient turnover was slower in task allocation wards, and the ratio of discharges to deaths was lower. Several nursing practices were seen to be pushing patients into dependency. The findings indicate that a considerable proportion of the dependency of elderly patients can be iatrogenic, and the formulae for calculating the number of nurses needed on the basis of patient's dependency are inadequate.

Aged↗
PubMed1985

Sequential administration of thymidine, 5-fluorouracil, and PALA. A phase I-II study.

Twenty-seven patients with colorectal adenocarcinoma, (12) non-small cell bronchogenic carcinoma, (11) gastric adenocarcinoma (3), and adenocarcinoma of unknown primary lesion (1) were treated with the combination of thymidine (TdR), 5-fluorouracil (FU), and N-phosphonacetyl-L-aspartic acid (PALA). PALA 1 g/m2 was given over 1 hour on day 1, followed on day 2 by 30 g of TdR given over 3 hours. FU, 150-300 mg/m2, was administered sequentially over 1 hour immediately following TdR infusion. There were no responses seen using this dose schedule. Gastrointestinal and central nervous system toxicities were dose-limiting. Myelosuppression was seen at all dose levels and was not dose related. Fever and infection occurred in 16% and 3% of the courses. The maximum tolerated dosages on this schedule were PALA, 1 g/m2; TdR, 30 g; and FU, 250 mg/m2. Pharmacologic studies done revealed the following half-lives: TdR, 1.6 hours; thymine, 5.0 hours; FU, 6.8 hours; and FUDR, 3.7 hours. The significant prolongation of the half-life of FU with this drug combination implies that the tumor tissues may be exposed longer to the anticancer action of FU.

Adenocarcinoma↗
PubMed1985

Nurse/patient dependency--is it iatrogenic?

It is often assumed that nursing care is given in response to the patient's degree of incapacity. This study indicates that rather than nursing care arising as a response to patients' dependency, nursing care is producing dependency. A considerable proportion of the measured dependency of 168 elderly patients arose from the type of nursing care they received--it was iatrogenic. Task allocation nursing was found to be positively unhealthy for elderly long-stay patients, whilst individualized care (nursing process) was associated with lower patient dependency, a shorter hospital stay and a better chance of surviving the hospital stay. The findings demonstrate the inadequacy of nurse staffing formulas which are based on patient dependency. It is suggested that despite the rising numbers of very old people in the population, the elimination of nurse-induced dependency could reduce the level of dependency in geriatric wards.

Aged↗
PubMed1985

The relationship between nursing theory and nursing practice.

During the past two decades, redefinition of many of the beliefs and assumptions which underly nursing appears to have contributed to an increasing divergence between nursing theory and nursing practice. Nurses who are theorists and educationalists, and nurses who are engaged in nursing practice tend to use different vocabularies, to have differing perceptions of patients and of nursing, and to value different kinds of nursing knowledge. Some of the divergences between nursing theory and nursing practice are considered, and suggestions made about how theory and practice might be reconciled.

Communication↗
PubMed1985

A double-blind controlled trial of etretinate (Tigason) and ibuprofen in psoriatic arthritis.

Etretinate (Tigason) and ibuprofen have been compared in a double-blind controlled trial in psoriatic arthritis to see if we could confirm a specific action for this vitamin A derivative suggested from earlier uncontrolled studies. Eleven out of 20 patients completed 24 weeks of therapy with etretinate (up to 0.5 mg/kg/day) whereas only 1/20 patients completed 24 weeks of therapy with ibuprofen alone. Etretinate improved skin lesions, and this may have encouraged patients to persist with it. Improvement of statistical significance was seen for articular index in both groups. In addition significant improvement in ESR, haemoglobin, C-reactive protein, and histidine occurred in the etretinate group. The main side effects of etretinate (which may preclude its use at a higher dose in this condition) included cracked and dried lips and sore mouth.

Adolescent↗
PubMed1985

Pulmonary function in singers and wind-instrument players.

Previous studies suggest that pulmonary function of singers and wind-instrument players may be better than normal control subjects due to breath-control training; however, prior studies were poorly controlled or limited in scope. In the present study, we compare 34 singers and 48 wind instrumentalists with a control group of 31 string or percussion instrumentalists using a pulmonary questionnaire, measurements of inspiratory and expiratory pressures, and spirometry. We found no significant difference between groups in maximum voluntary ventilation, forced expiratory volume in one second (FEV1), forced vital capacity (FVC), mean forced expiratory flow during the middle half of the FVC, the FEV1/FVC, peak expiratory pressure, or peak inspiratory pressure, independently or when corrected for age, sex, height, weight, years performing, smoking, presence or absence of cough, or sputum production. Smoking correlated negatively with measurements of pulmonary function in all groups. There was evidence of a heightened awareness of health among singers, who exercised more and smoked less than their colleagues. The differences in health habits may account in part for the myth of improved pulmonary volumes among singers.

Adult↗
PubMed1985

Stenosis of main bronchi mimicking fixed upper airway obstruction in sarcoidosis.

An unusual site and cause of disabling inspiratory and expiratory airflow limitation mimicking fixed upper airway obstruction is reported in two patients with sarcoidosis who had stenosis of almost the entire lengths of both main bronchi. The observed flows were consistent with a cross sectional airway diameter of 3 mm. The lumen of the trachea and proximal airways was not compromised.

Adult↗
PubMed1985

Acute mercury poisoning with severe chronic pulmonary manifestations.

This report describes a patient who developed acute chemical pneumonitis following overexposure to metal mercury vapor. The exposure occurred in a gold extraction facility where a gold-mercury amalgam was heated in a confined area. Prompt treatment with penicillamine and corticosteroids was instituted; radiologic pulmonary infiltrates disappeared within a week, but there was little change in the pulmonary function abnormalities (restriction and diffusion impairment) over the period of 11 months of follow-up. This raises the possibility of persistent pulmonary function impairment after metal mercury vapor-induced chemical pneumonitis.

Adult↗
PubMed1985

New class of inhibitors specific for human renin.

Seven active tetrapeptide amides characterized by a C-terminal phenylalanyl aminoadamantane (PheNHAd) sequence, were identified by selective testing for human renin inhibitory activity among compounds with adjacent hydrophobic groups and molecular size equivalent to 3-5 amino acid residues. The new inhibitors were compared with known renin inhibitors (RIP, pepstatin, H-77) and opioid analgesic agents (Met-enkephalin, morphine), with the following results: The new inhibitors were active against human renin (IC50 approximately 10-5M), but inactive against rat renin and pepsin. Although active in opiate receptor binding studies (IC50 approximately 10(-7)M), they were, with few exceptions, inactive in the mouse writhing and hot plate tests for analgesia. SAR studies suggested a separation of the renin inhibitory from the analgesic activity of enkephalin analogs. Preliminary experiments with sodium-depleted rhesus monkeys indicated hypotensive activity for three of the new inhibitors at 3 mg/kg i.v., and RIP at 1 mg/kg. The recently reported clinical hypotensive properties of RIP (Zusman et al., Trans. Assoc. Am. Physicians 96:365, 1983) along with the present comparative studies suggest that the new inhibitors may lead to clinically useful agents.

Amantadine↗
PubMed1985

Factors related to the incidence of the malabsorption syndrome.

Malabsorption syndrome has been produced in the laboratory with chicks and feed supplied by poultry integrators who had experienced the problem. Feed supplied by one company produced chicks that developed pale shanks and had apparent malabsorption of certain nutrients. One chick source also had a statistically lower pigmentation score than the other.

Animal Feed↗
PubMed1985

Antithyroglobulin monoclonal and autoantibodies cross-react with an orbital connective tissue membrane antigen: a possible mechanism for the association of ophthalmopathy with autoimmune thyroid disorders.

The possibility that Graves' ophthalmopathy and autoimmune thyroid disorders may be associated because of autoimmune reactions against antigens shared between human orbital and thyroid tissues was investigated using anti-thyroglobulin (Tg) monoclonal and autoantibodies. Eleven of 16 mouse monoclonal antibodies (MCAB) tested reacted, in an enzyme-linked immunosorbent assay (ELISA), with an antigen in human orbital connective tissue membranes (OCTmem), but not with the OCT soluble fraction, or with membrane or soluble fractions of human eye muscle, lacrimal gland or skin connective tissue. The anti-OCTmem activity was absorbed by OCTmem and Tg, but not by liver membranes or bovine serum albumin (BSA). In preliminary studies four out of 113 human MCAB against thyroid or orbital tissue antigens showed reactivity restricted to Tg and OCTmem. Sera from approximately 50% of patients with autoimmune thyroid disorders, with or without ophthalmopathy, also reacted with OCTmem. The autoantibody activity correlated closely with serum titres of antithyroglobulin but not with the presence, duration, or severity of the eye disease. The OCTmem reactivity was absorbed by Tg, thyroid membranes, and OCTmem but not liver membranes, membranes prepared from other orbital tissues, or BSA. The OCTmem-Tg shared antigen site appeared not to be native thyroglobulin since, (i) MCAB and serum autoantibodies did not react with the cytosol fraction of OCT, and (ii) because the membrane antigen was not solubilizable. Because not all patients with ophthalmopathy have detectable anti-Tg antibodies and, conversely, because not all patients with detectable anti-Tg antibodies develop ophthalmopathy it is unlikely that autoimmunity against a OCTmem-Tg shared antigen is the primary mechanism of Graves' ophthalmopathy, although this possibility has not been excluded. On the other hand the reaction of anti-Tg autoantibodies with OCT membranes may be a model for other autoimmune reactions against other thyroid-orbital tissue-shared antigens. While the pathogenesis of Graves' ophthalmopathy is likely to be multifactorial, humoral and cellular reactions against primary orbital antigens, thyroid-orbitol tissue shared antigens, or both, are likely to play important roles.

Adult↗
PubMed1985

Measurement of total-body cobalt-57 vitamin B12 absorption with a gamma camera.

Previously described techniques for the measurement of the absorption of [57Co]vitamin B12 by total-body counting have required an iron room equipped with scanning or multiple detectors. The present study uses simplifying modifications which make the technique more available and include the use of static geometry, the measurement of body thickness to correct for attenuation, a simple formula to convert the capsule-in-air count to a 100% absorption count, and finally the use of an adequately shielded gamma camera obviating the need of an iron room.

Absorption↗