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Biomedical subjects

J L Day

Publications and source records attributed to J L Day.

At least 37 records · Page 2Linked to original sources
PubMed1988

The feasibility of a potentially 'ideal' system of integrated diabetes care and education based on a day centre.

A new system of clinical and educational care designed to replace traditional diabetic clinics is described. The overall aims were to provide adequate consultation time, patient access according to diabetic and social needs, minimal waiting time, continuity with experienced staff and objective based learning programmes in an environment suited to learning. This was achieved by changing the role of the diabetes nurse specialist from undertaking delegated tasks to providing primary consultative care, reorganization of existing staff and provision of a purpose designed unit. This gave sufficient flexibility to arrange daily early morning and weekly evening clinic sessions for routine diabetes counselling and medical audit with primary education scheduled at other times. A year's experience showed that our major targets had been met, with the provision of adequate consultation time, halving of waiting time, ease of patient access and continuity with either the doctor or nurse in consulting role. Default rates have fallen and patient and staff morale has improved substantially. Apart from an underestimate of receptionist and a small increase in technician hours, these changes have been achieved within the predicted small revenue cost.

Appointments and Schedules↗
PubMed1987

Problems of comprehensive shared diabetes care.

In its first year 747 diabetics were entered into a comprehensive shared care scheme in which general practitioners agreed to follow up their own patients. After two years patients were recalled to hospital for review through a computer based recall system. Analysis of the first 209 patients reviewed showed that the recall system worked well with failure to trace only eight patients. Six new cases of foot ulcer, 15 of retinopathy, 14 of macular degeneration, and 15 of raised blood pressure requiring treatment were detected at review. Sixty four patients appeared to have had no check on their diabetes during the two years. Of the 117 with written evidence in their cooperation books that they had received some diabetic supervision, many had had no measurement of weight (32), blood pressure (49), or urine (68) or blood glucose (70), and only 55 had had foot and 65 eye examination. This erratic and generally poor standard of supervision suggests that much tighter organisation is required within each practice, with time being set aside specifically for care of diabetics. Practice nurses could have an important role in the delivery and organisation of care.

Comprehensive Health Care↗
PubMed1987

Screen-film mammographic technique for breast cancer screening.

The values of dose and signal-to-noise ratio (SNR) for many techniques and breast thicknesses were computed and compared with a reference technique and breast thickness to provide a valid basis upon which to select a screening technique for screen-film mammography. The reference consisted of a Min-R/OM1 combination (or its equivalent) exposed through a 4.5-cm thick breast via 28 kV and a molybdenum target-beryllium window tube with a 0.03-mm Mo filter. Radiographs of an improved breast phantom were used to relate computed relative SNR values of techniques to diameters of the smallest calcific and soft-tissue objects demonstrated in mammograms. Without use of a grid, four Mo target/filtration combinations yielded similar computed dose and SNR levels, as did a tungsten target tube operated at 23 kV without a filter. Operation of the latter tube at 27.5 kV with a 0.051-mm rhodium filter should reduce dose by half but also SNR by 22%. However, such operation with a grid should greatly improve imaging moderate to large breasts without increasing dose over reference values.

Breast Neoplasms↗
PubMed1986

Regression of posterior uveal malignant melanomas after cobalt plaque radiotherapy.

We reviewed the records of 17 patients with posterior uveal malignant melanoma who had been followed for at least 3 months prior to cobalt plaque radiotherapy and whose tumor had been documented to enlarge in thickness during that interval. We evaluated the relationship between the rates of pretreatment tumor enlargement and post-treatment tumor shrinkage using linear regression analysis. We found that the rate of postirradiation tumor shrinkage correlated strongly with the rate of preirradiation tumor enlargement regardless of whether the pretreatment rate of growth was slow, intermediate or rapid. We speculate that the more rapidly regressing tumors were more mitotically active than their more slowly regressing counterparts. If true, the survival rate of patients whose posterior uveal malignant melanomas regress rapidly following radiation therapy may prove to be worse than that of patients whose tumors regress slowly.

Brachytherapy↗
PubMed1985

Malignant melanoma of the eye: treatment of posterior uveal lesions by Co-60 plaque radiotherapy versus enucleation.

Survival rates and visual acuity of 100 patients treated for posterior uveal malignant melanoma by cobalt-60 plaque radiotherapy were compared with 150 patients treated by enucleation for the same disease. Life-table comparisons of the entire group showed significant differences in survival rates, with plaque radiotherapy patients appearing to fare better. However, when patients with small or medium tumors were compared, only slight differences were seen, implying that criteria used to select patients for treatment may affect interpretation. The two groups were also compared using the Cox proportional hazards model, which predicts survival based on the impact of clinical variables. In this analysis, the survival rates of the plaque radiotherapy group were no worse than those of the enucleation group. The advantage of conservative therapy lies in the potential to preserve useful vision over a considerable time. Because patients were specifically selected for treatment modality and because the study size used to calibrate the Cox model was small, the results of this study must be interpreted with caution.

Cobalt Radioisotopes↗
PubMed1984

Adrenergic mechanisms in the control of plasma lipids in man.

The effects on plasma lipids of beta-blocking antihypertensive agents with differing degrees of selectivity and intrinsic sympathomimetic activity were studied. The interrelationship between changes in lipid factors, lipoprotein lipase function, the degree of response, and pretreatment characteristics were examined. Beta-adrenergic blockade increased plasma triglycerides but decreased high-density lipoprotein cholesterol. Cardioselective drugs (atenolol and metoprolol) had less effect on triglyceride and very low-density lipoprotein cholesterol than the nonselective beta blockers (propranolol and oxprenolol). Inhibition of lipoprotein lipase was suggested by a reduction of the fractional removal rate of triglyceride in conjunction with increased total and very low-density lipoprotein cholesterol levels and reduced high-density lipoprotein cholesterol. Consistent decreases in free fatty acids lend argument against elevated triglyceride synthesis.

Adrenergic beta-Antagonists↗
PubMed1984

Regression of posterior uveal melanomas following cobalt-60 plaque radiotherapy.

A method has been devised for evaluating the rate and extent of regression of the first 100 consecutive patients with a posterior uveal melanoma that we had managed by Cobalt-60 plaque radiotherapy at Wills Eye Hospital. It was found that the "average" posterior uveal melanoma in the series did not regress rapidly to a flat, depigmented scar but shrank slowly and persisted as a residual mass approximately 50% of the thickness of the original tumor at 54 months following Cobalt-60 plaque radiotherapy. We also found that the rate and extent of regression of the tumors in patients who subsequently developed metastatic melanoma were not appreciably different than the rate and extent of regression of the tumors in patients who remained well systemically. These observations indicate that the rate and extent of regression of posterior uveal melanomas following Cobalt-60 plaque radiotherapy are poor indicators of the prognosis of the affected patients for subsequent development of clinical metastatic disease.

Brachytherapy↗
PubMed1984

Dosage evaluation in mammography.

Estimates of breast dose per view are needed for selection of mammographic techniques and verification of their proper use. However, accurate dosimetry requires standardization of both the methodology and the assumed breast composition. Because several different methods have been reported, the authors developed a simple and reproducible method using a reference "average breast" composition of 50/50% water/fat by weight. Working curves were derived for average glandular and whole-breast dose per unit of exposure in air vs. HVL and thickness. When these curves are combined with on-site measurements of exposure per view, one obtains values of dose per view for each technique. Factors were also computed to correct dosage from the reference composition to other breast compositions.

Adult↗
PubMed1983

Effect of allopurinol on the pharmacokinetics of 6-mercaptopurine in rabbits.

The effect of allopurinol on the pharmacokinetics of 6-mercaptopurine (6MP) was studied in rabbits. 6MP alone and in combination with allopurinol was administered i.v. at two dosage levels (2.5 and 20 mg/kg). The plasma concentrations of 6MP and its major metabolite, 6-thiouric acid, were assayed by high-performance liquid chromatography. Plasma levels of 6MP decay biexponentially. The influence of allopurinol on the pharmacokinetic parameters of 6MP was as follows: (a) a 2-fold increase in the half-life and area under the concentration-time curve; (b) a 2-fold decrease in the total body clearance; and (c) an approximate 3-fold decrease in elimination rate constant. The influence of allopurinol on the pharmacokinetic parameters of 6-thiouric acid was negligible. The results suggest that allopurinol serves to increase the plasma level of 6MP by inhibiting its catabolism and thus contributing to a greater availability of 6MP to the tissues.

Allopurinol↗
PubMed1982

Adrenergic mechanisms in control of plasma lipid concentrations.

The mechanisms of the changes in plasma lipids concentrations observed after beta-blockade were examined in 53 patients with hypertension receiving treatment with atenolol, metoprolol, propranolol, and oxprenolol in a randomised cross-over trial. Significant increases in mean plasma total and very-low-density lipoprotein (VLDL) triglyceride and reductions in high-density lipoprotein (HDL) cholesterol and free fatty acids concentrations wer observed with all four drugs, the increase in plasma triglyceride concentration being greatest after propranolol and oxprenolol. No significant changes were observed in total of LDL cholesterol concentrations, but HDL:LDL ratios and HDL cholesterol as a proportion of total cholesterol fell significantly. Thus plasma lipid concentrations should be monitored after three to six months of long-term treatment. Changes in triglyceride, HDL cholesterol and free fatty acid concentrations were associated with a highly significant reduction in clearance of soya oil (Intralipid) in 25 patients studied but were unrelated to changes in blood pressure. The fall in HDL cholesterol and rise in free fatty acid concentrations were significantly less in those with initially reduced HDL cholesterol or raised free fatty acid concentrations respectively. It is proposed that unopposed alpha stimulation inhibits lipoprotein lipase with a subsequent rise in plasma triglyceride and fall in HDL cholesterol concentration. Analysis of the relation between pretreatment concentrations and subsequent changes suggests that excessive alpha stimulation may impair production of HDL cholesterol in those with low HDL cholesterol concentrations before treatment. Subtle catecholamine-mediated changes in plasma lipid concentrations might provide a mechanism for the relation between stress and the development of cardiovascular events.

Adrenergic beta-Antagonists↗
PubMed1982

Malignant intraocular tumors.

The role of the radiation therapist in the management of malignant intraocular tumors is changing. With more active identification of malignant intraocular tumors, and a better recognization of the manner in which one can deal with problems of radiation sensitivity, radiation techniques of all sorts will be more actively employed in the treatment of these tumors. Special techniques must be selected for appropriate circumstances of management in order to diminish to an absolute minimum the impact upon the lens, the impact upon visual acuity and the impact upon the cornea. Cobalt-60 plaques are being used more commonly in the treatment of melanomas of the choroid, and the role for radiation therapy in the management of retinoblastoma is changing markably to where it may be used as the primary treatment program rather than enucleation. In metastatic disease involving the uveal tract, radiation therapy has assumed the most important role for management. Chemotherapy should be considered as an active adjuvant in the management of not only those individuals with retinoblastoma but also in those identified circumstances where metastases to the uveal tract are being treated. The role for chemotherapy or immunotherapy in malignant melanoma is unclear.

Aged↗
PubMed1982

Cobalt plaque therapy of posterior uveal melanomas.

One hundred patients with choroidal melanomas who were treated by the authors with cobalt plaque radiotherapy were analyzed with regard to tumor regression, visual results, complications, and mortality rate. The follow-up period at the time of this writing ranged from one to five years. These preliminary observations indicate that cobalt plaque radiotherapy induces tumor regression in 96% of cases, preserves useful vision in many cases and has fewer complications during the one- to five-year follow-up period than previously believed.

Adult↗