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Biomedical subjects

M MacLeod

Publications and source records attributed to M MacLeod.

At least 37 records · Page 2Linked to original sources

Renal osteopenia - an assessment of long-term therapy with vitamin D analogues.

Renal bone disease was assessed for an average of 5.5 years in 9 patients on maintenance haemodialysis. The investigative methods included serial biochemical estimations, radiographic skeletal surveys and quantitative bone histology. Repeated bone mineral analyses and neutron activation analyses of a hand were also performed in order to monitor changes in skeletal calcium content. Before treatment, progressive osteodystrophy was demonstrated by all techniques. Following therapy with the vitamin D analogues, all patients noted symptomatic improvement; serum alkaline phosphatase reverted to normal and serum parathyroid hormone concentrations decreased. Radiographically, subperiosteal erosions healed while the histological features of osteomalacia and osteitis fibrosa were abolished. Both bone mineral and neutron activation analyses indicated that progressive skeletal demineralisation had been halted. However, a sustained increase in the overall mineral content of bone was not demonstrated. Thus, vitamin D therapy although improving the biochemical, radiological, and histological features of renal osteodystrophy may not restore bone mass to osteopenic bone.

Adult

Mefenamic acid: an under-rated antirheumatic?

A double-blind crossover study was carried out in 18 patients with classical rheumatoid arthritis to assess the effectiveness of mefenamic acid (500 mg t.d.s.) compared with placebo or indomethacin (25 mg q.d.s.). Each treatment was given for 1 week and subjective and objective assessments were carried out at the end of each period. Results showed that both mefenamic acid and indomethacin were significantly better than placebo in most parameters. Although duration of morning stiffness and patient preference favoured indomethacin it was considered that there was no demonstrable difference of any clinical significance between the two active medications.

Adult

Renal CO2 production from glutamine and lactate as a function of arterial perfusion pressure in dog.

The energy cost of renal function in the intact kidney of the dog was assessed at a series of arterial perfusion pressures. Pressure was varied by partially inflating a balloon at the tip of a catheter positioned in the aorta above the origins of the renal arteries. Either L-[U-14C]-lactate was infused intravenously in tracer amounts throughout each experiment. Total renal CO2 production and 14CO2 production from each isotope permitted assessment of total renal oxidative metabolism and the proportions derived from the two major substrates of the kidney. Stepwise inflation of the aortic balloon progressively lowered glomerular filtration rate, renal blood inflow, filtered and consequently reabsorbed Na+, total renal CO2 production, and 14CO2 derived from glutamine and lactate. The percent of total CO2 derived from lactate decreased more or less in proportion to the decrease in percent of total CO2 produced. Results were consistent with the view that reabsorption of sodium is the major energy sink of the kidney. They suggest that the oxidation of glutamine supplies energy for tubular transport and basal demands such as synthesis of hormones and maintenance of structure, whereas the oxidation of lactate supplies energy mainly for transport activities.

Acidosis

The investigation and treatment of renal bone disease.

Neutron activation analysis of a hand has been used to monitor changes in skeletal calcium content of patients undergoing maintenance hemodialysis. Assessed by this technic supplementary magnesium therapy was of value of reducing the progressive losses of skeletal calcium in a proportion of the patients receiving maintenance hemodialysis. Oral calcium supplements produced a decrease in the skeletal calcium losses of all the patients studied. 1-alpha-hydroxycholecalciferol, a potent vitamin D analogue, caused a significant increase in the calcium content of bone in three patients receiving maintenance hemodialysis; it may prove to be a safe and effective form of therapy for azotemic osteodystrophy.

Adult

I alpha-hydroxycholecalciferol: a treatment of renal bone disease.

Three patients with chronic renal failure on maintenance haemodialysis have been treated with 1 alpha-hydroxycholecalciferol (1 alpha-OHCC), a synthetic vitamin D analogue. A daily dose of 2 mug by mouth produced a significant increase in both calcium absorption from the gastrointestinal tract and calcium content of bone. Treatment with 1 alpha-OHCC appears to be effective in cases of metabolic bone disease associated with chronic renal failure.

Administration, Oral

Clinical evaluation of two daily doses of naproxen and indomethacin: result of a double-blind crossover trail.

A double-blind crossover clinical trial is reported on the effects of naproxen in two doses, 500 mg. and 750 mg. daily, and 100 mg. indomethacin daily in 23 patients with classical rheumatoid arthritis, each drug being given for 1 week. The results show that there was little to choose between the drugs and that there was clinical equivalence between the two doses of naproxen. Radioactive pertechnetate (99mTc) joint uptakes were depressed by both naproxen and indomethacin, indicating anti-inflammatory effect.

Administration, Oral

The investigation and treatment of renal osteodystrophy.

Skeletal demineralisation was measured for two years in 16 patients on maintenance haemodialysis; the technique employed was neutron activation analysis of a hand. The magnesium concentration of the dialysate was increased in six of the patients; oral calcium carbonate was administered to seven patients and 1-alpha-hydroxycholecalciferol, a potent vitamin-D analogue was supplied to a further three patients. An increase in skeletal calcium content of a hand was noted in the groups of patients receiving supplementary calcium and 1-alpha-hydroxycholecalciferol. It is concluded that 1-alpha-hydroxycholecalciferol appears to be effective therapy for renal osteodystropy, that oral calcium supplements may promote skeletal remineralisation and that supplementary magnesium therapy may reduce the progressive losses of skeletal calcium from some patients on maintenance haemodialysis.

Adult

Treatment of muscle cramps during maintenance haemodialysis.

The effect of a slowly released oral preparation of sodium chloride (Slow Sodium) on the frequency and severity of muscle cramps, on blood pressure, and on body weight was compared with that of placebo in a double-blind cross-over trial in 19 patients on maintenance haemodialysis for end-stage renal failure. A significant reduction in both the frequency and severity of cramps was found while the patients were receiving the sodium chloride preparation and no significant alteration in blood pressure or body weight was detected.

Acute Kidney Injury

Thoracic chordoma with unusual radiographic features.

A case of chordoma involving the thoracic spine (T12) is reported. The plain film findings included lytic obstruction and partial collapse of a single vertebral body. Noncontrast CT and CT following Metrizamide myelography revealed vertebral body destruction with paravertebral and intraspinal soft tissue masses. Unusual findings in the case included a photon deficient area on nuclear medicine corresponding to the lesion and normal vascularity on spinal angiography. We know of no previous report describing chordoma as a "cold" defect on bone scanning.

Aged

Decision making of nurses practicing in intensive care in Canada, Finland, Northern Ireland, Switzerland, and the United States.

In this study, our intention was to describe the decision making of nurses practicing in intensive care, and the differences of nurses' decision making in Canada, Finland, Northern Ireland, Switzerland, and the United States. The instrument used in the study was a 56-item Likert-type questionnaire that has been used in previous studies and has proved to be a reliable tool. The target group comprised a nonrandom sample of nurses (N = 314) from five countries. The samples are not representative; therefore, the results in these cases cannot be generalized. The results showed that the decision making of nurses practicing in intensive care was broadly based, and that there were some country differences in data collection, problem definition, and planning. In contrast, decision making related to the implementation and evaluation of nursing is quite similar in the different countries. Canada and the United States on the one hand, and Finland, Northern Ireland, and Switzerland on the other, showed more similarities with each other in data collection, problem definition, and nursing planning related to decision making. Neither experience nor nurse's knowledge structure was associated with different decision-making approaches.

Canada