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Biomedical subjects

P Tothill

Publications and source records attributed to P Tothill.

At least 55 records · Page 3Linked to original sources
PubMed1986

Corticosteroids and bone mass in asthma: comparisons with rheumatoid arthritis and polymyalgia rheumatica.

Bone mass has previously been shown to be reduced at peripheral bone sites in patients with bronchial asthma receiving corticosteroids. To assess whether total bone mass is reduced in asthma total body calcium was measured by in vivo neutron activation analysis in patients receiving various treatments for asthma and compared with results from normal controls and patients with rheumatoid arthritis and polymyalgia rheumatica. Compared with controls total body calcium was reduced by 13.6% (p less than 0.001) in patients with asthma receiving daily oral corticosteroids but by only 9.0% (p less than 0.005) in a similar group of patients who had received oral calcium supplements at the start of their corticosteroid treatment. Total body calcium was also reduced in a group of patients receiving only inhaled corticosteroids (8.8%; p less than 0.001) but not significantly reduced in a small group of patients with asthma who had never received these drugs. When compared with controls a group of patients matched for age and for dose of corticosteroids given for rheumatoid arthritis had a similar reduction in total body calcium to the patients with asthma receiving daily oral treatment (17.7%; p less than 0.001), but no such reduction was shown in patients with polymyalgia rheumatica. These findings suggest that the risk of bone loss with low dose oral corticosteroids in similar in asthma and rheumatoid arthritis. Further work is required to assess the clinical relevance of small losses of bone associated with the use of inhaled corticosteroids.

Administration, Oral↗
PubMed1986

Is gastric emptying abnormal in duodenal ulcer?

To investigate the possibility that an abnormality of gastric emptying exists in duodenal ulcer and to determine if such an abnormality persists after ulcer healing, scintigraphic gastric emptying measurements were undertaken in 16 duodenal ulcer patients before, during, and after therapy with cimetidine; in 12 patients with pernicious anemia, and in 12 control subjects. No difference was detected in the rate or pattern of gastric emptying in duodenal ulcer patients before and after ulcer healing with cimetidine compared with controls, but emptying of the solid component of the test meal was more rapid during treatment with the drug. Comparison of emptying patterns obtained in duodenal ulcer subjects during and after cimetidine treatment with those obtained in pernicious anemia patients and controls revealed a similar relationship that was characterized by a tendency for reduction in the normal differentiation between the emptying of solid and liquid from the stomach. The similarity in emptying patterns in these groups of subjects suggests that gastric emptying of solids may be influenced by changes in the volume of gastric secretion. The failure to detect an abnormality of gastric emptying in duodenal ulcer subjects before and after ulcer healing calls into question the widespread belief that abnormally rapid gastric emptying is a feature with pathogenetic significance in duodenal ulcer disease.

Achlorhydria↗
PubMed1986

Total and peripheral bone mass in patients with psoriatic arthritis and rheumatoid arthritis.

Psoriatic arthritis is thought to be associated with periarticular osteoporosis while rheumatoid arthritis may be associated with generalised as well as periarticular bone loss. To assess the extent of total and peripheral bone loss in these two diseases, total body calcium was measured by in vivo neutron activation analysis and peripheral bone mass was assessed by metacarpal indices in age-matched patients with psoriatic arthritis and rheumatoid arthritis treated with nonsteroidal anti-inflammatory drugs alone. In comparison with age and sex-matched normal controls, total and peripheral bone mass was normal in psoriatic arthritis. There were significant reductions in total (6.2% in men; 7.9% in women) and peripheral (10.9% in men; 12.8% in women) bone mass in patients with rheumatoid arthritis compared with controls. Peripheral bone mass was significantly correlated with the degree of radiographic damage in male and female patients with rheumatoid arthritis. The mean annual loss of total body calcium was insignificant in psoriatic arthritis (0.6% in men; 1.9% in women) but markedly greater in rheumatoid arthritis (4.4% in men; 2.7% in women). The data suggested that total and peripheral bone loss is greater in rheumatoid arthritis than psoriatic arthritis. Substantial reductions in peripheral bone mass in patients with rheumatoid arthritis not receiving corticosteroids may account in part for the small reductions in total bone mass.

Adult↗
PubMed1986

Changes in total body calcium following surgery for primary hyperparathyroidism.

The aims of this study were to measure the deficit in total body calcium in patients with primary hyperparathyroidism and to observe whether this deficit was reversed by parathyroidectomy. Total body calcium was measured in five women and three men preoperatively, and the mean was found to be 11% below that of age-and sex-matched controls after normalization for postmenopausal age and body size (P less than 0.01). Following parathyroidectomy, repeat total body calcium measurements showed an increase of 7.1% over an average period of 14 months (P less than 0.03). In patients with primary hyperparathyroidism, total body calcium returns toward normal following surgical removal of the adenoma.

Adenoma↗
PubMed1986

The distribution of blood flow to the whole skeleton in dogs, rabbits and rats measured with microspheres.

The distribution of blood flow to the skeleton was studied by injecting radioactive microspheres into the hearts of anaesthetised adult animals and measuring activity in individual bones and groups of bones. The mean proportion of the cardiac output delivered to the whole skeleton was 7.5% in dogs, 4.2% in rabbits and 4.5% in rats. The results throw doubt on the value for rats of 27% published by Brookes. There was a wide range of flow per unit mass of bone in different parts of the skeleton, demonstrating the inaccuracy of predicting total skeletal flow from measurements on a single bone. The relative distribution to different parts of the skeleton was similar in the three species, but there were quantitative differences.

Animals↗
PubMed1986

The seasonal variation of total body calcium.

Total body calcium was measured using in vivo neutron activation analysis in 156 patients with rheumatic diseases at six-month intervals. Evidence of seasonal variation was sought by relating deviation from a linear change to the month in which the measurement was made. A cyclic regression fitted to the data had an amplitude of 0.25% but a significance of only P = 0.08. The calcium balance studies of Malm were re-analysed to quantify the seasonal variation he had demonstrated in one group of men. The deduced variations of body calcium were highly significant, with a phase and amplitude very similar to the regression of our data. Both analyses differed from two previous reports of seasonal variations of part-body bone mineral of much greater amplitude and different phase.

Calcium↗
PubMed1986

Bone loss in rheumatoid arthritis and primary generalized osteoarthrosis: effects of corticosteroids, suppressive antirheumatic drugs and calcium supplements.

The annual rate of bone loss in rheumatoid arthritis (RA) and primary generalized osteoarthrosis (PGOA) was determined by measurement of total body calcium (TBCa). The mean annual rate of bone loss in 24 patients with RA treated with nonsteroidal anti-inflammatory drugs (NSAIDs) alone was 3.4%. This rate of bone loss was not reduced in ten RA patients responding to suppressive antirheumatic drugs (4.3%) or seven patients receiving oral calcium supplements (4.5%). The mean annual rate of loss of TBCa in 19 patients with PGOA was 1.6%, a figure which probably represents age-associated bone loss. The rate of bone loss in PGOA was significantly less than that in RA patients not receiving corticosteroids. The mean annual rate of change of TBCa in 30 RA patients receiving corticosteroids (+0.7%) was significantly less than that in any of the other RA groups despite an initial normalized bone mass which was significantly less than in those RA patients receiving NSAIDs alone. The data supported the hypothesis that bone loss occurred early in the course of corticosteroid therapy and thereafter the drugs might have a protective effect on the loss of bone in RA.

Adrenal Cortex Hormones↗
PubMed1986

Bone mass in ankylosing spondylitis.

To assess bone mass in ankylosing spondylitis (AS) we have measured total body calcium, bone mineral content of the lumbar spine and metacarpal indices in groups of patients with AS. Mean total body calcium was reduced by 5.3% (p less than 0.05) in 20 patients compared with controls. The mean annual loss of bone, assessed over an 18 month period in 17 patients, was 2.9% (p less than 0.001). Compared to controls, bone mineral content was increased by 28% (p less than 0.05) in 8 male patients while metacarpal indices were normal in 18 male and female patients. The results of total body calcium measurements give support to the hypothesis of a minor increase in bone turnover in AS. The increased bone mineral content in the male patients may relate to syndesmophyte formation.

Adult↗
PubMed1985

The variation with flow-rate of the extraction of bone-seeking tracers in recirculation experiments.

Radioactive microspheres were injected into the hearts of anesthetized dogs and the reference organ technique used to determine cardiac output. Blood flow to the leg bones was then obtained from microsphere uptake. Simultaneous injections of the bone-seeking radiotracers 85Sr and, in fewer animals, 18F and 99mTc methylene diphosphonate similarly gave their clearances from the blood by bone over a period of 5 min. The ratio of clearance to flow (extraction ratio) was found to be flow-dependent, falling from near unity at low flow rates to about 0.4 at higher flow rates. The results are in general accordance with the Renkin theory of capillary permeability but do not fit exactly to the concept of a constant product of permeability and surface area, perhaps due to the heterogeneity of the model. The findings confirm conclusions based on tibial nutrient artery perfusion experiments and demonstrate that skeletal blood flow cannot be measured by the clearance of bone-seeking tracers. There were substantial differences of blood flow normalized for weight between the bones of a given animal.

Animals↗
PubMed1985

Measurement of tendon blood flow in rabbits by microsphere uptake and 133Xe washout.

Blood flow was measured in the calcaneal tendons of rabbits using the techniques of labelled microsphere uptake and 133Xe washout simultaneously. There was no correlation between the results obtained with the two methods in individual animals. It is doubtful if the assumptions underlying the 133Xe washout technique are valid when it is used to measure blood flow in tendons.

Animals↗
PubMed1985

Changes in total body calcium after renal transplantation: effect of low-dose steroid regime.

Total body calcium was measured in 8 men and 4 women, aged 20-51 years, undergoing kidney transplantation. The initial measurement was made within 8 weeks of operation and subsequent measurements up to 33 months postoperatively. Transplant rejection was prevented by low-dose prednisolone therapy (20 mg/day). 2 patients underwent parathyroidectomy for hypercalcaemia, and their total body calcium increased by 29 g (3%) and 66 g (8%). In the remainder the mean annual change was -0.9% (3.7, SD) over an average follow-up period of 17 months. This fall in total body calcium was statistically insignificant and was smaller than that previously described in patients treated with higher doses of steroids.

Adult↗
PubMed1984

Invalidity of single-passage measurements of the extraction of bone-seeking tracers in rats and rabbits.

Single-passage experiments in which bone-seeking tracers are injected arterially at the same time as microspheres to determine an extraction ratio are only valid if the maximum transit time through bone is less than the minimum recirculation time. This validity was investigated by injecting various intravascular and more diffusible tracers into the hearts or aortas of rats and rabbits at different times before the rapid cessation of circulation. At no time between 4 and 60 s after injection did the bone concentration of any of the tracers fall to negligible values. Removal of unbound tracer is therefore not complete before recirculation starts, and the single-passage technique is invalid. Measurements of bone blood flow based on the clearance of 18F cannot be substantiated, as its extraction is flow dependent.

Animals↗
PubMed1984

The early effects of sympathectomy on bone blood flow.

Several laboratories, including our own, have investigated the physiology of bone blood flow by perfusion of the tibia via the nutrient artery. Any damage caused to the nerve supply by cannulation of the artery might affect the results. The possible effect of such damage was investigated by measuring blood flow to the dog tibia using a microsphere technique, before and after sympathectomy. No effect was found and the tibial nutrient artery is therefore a suitable vessel for perfusion when estimating nutrient exchange in bone.

Animals↗
PubMed1984

Bone blood flow measurement.

Methods of determining blood flow in bone are described and compared. Those based on clearances of bone-seeking tracers are inaccurate because of the variation of extraction with flow. The use of radioactive microspheres is the best available technique for measurements in animals; applications of this method are given. The washout of diffusible tracers is of limited use.

Animals↗
PubMed1984

Bone mass in nodal primary generalised osteoarthrosis.

Previous studies of patients with primary osteoarthrosis of the hip have suggested an increase in bone mass compared with control populations. Nodal primary generalised osteoarthrosis is known to have a strong familial tendency. To test the hypothesis that this tendency might also lead to increased bone mass, total body calcium has been measured by in-vivo neutron activation analysis and cortical area calculated from measurements of metacarpal indices in 15 female patients with primary generalised osteoarthrosis. The results have been compared with those from 12 healthy controls matched for age, menopausal status, and skeletal size. No significant differences were noted in the total body calcium or cortical area measurements between the 2 groups either before or after correction for skeletal size and menopausal status. No relationship was found between the grade of radiological osteoarthrosis in the hand and either bone mass parameter. Bone mass would not appear to be an important factor in the aetiopathogenesis of nodal primary generalised osteoarthrosis.

Bone Diseases↗
PubMed1984

Blood flow and clearance in tendons. Studies with dogs.

Blood flow in intact tendons in dogs was measured using 57Co-labelled microspheres and compared with the simultaneous clearance of a diffusible radionuclide, 85Sr, by the same tendons. Clearance was significantly greater than flow in all tendons, indicating that diffusion from surrounding tissues may be important in the nutrition of normal tendons.

Animals↗
PubMed1983

Whole-body and part-body turnover of 85Sr in Paget's disease.

The whole-body and part-body retention of 85Sr has been measured over a period of 150 days in 12 patients with Paget's disease, seven of whom were treated with calcitonin, starting 60 days after the 85Sr administration. Retentions were compared with those in a group of seven control subjects. The retention data were analysed using multiple exponential, single and double power-law and combined power law and exponential functions. The mean retention of 85Sr over a long period was greater in the Paget's patients than in the controls, 1.9 times at two months. No significant effect of calcitonin treatment was demonstrated. Part-body measurements based on profile scanning demonstrated a significantly increased uptake of 85Sr in sites where disease was present. The longer-term rate of disappearance from such sites was faster than from unaffected bones.

Aged↗