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Biomedical subjects

M Peacock

Publications and source records attributed to M Peacock.

At least 109 records · Page 6Linked to original sources
PubMed1986

The effect of transdermal oestrogen on bone, calcium-regulating hormones and liver in postmenopausal women.

Transdermal oestradiol, 100 micrograms/d, was used to treat 11 women suffering from postmenopausal symptoms. After 3 weeks therapy there was a significant rise in the plasma oestradiol into the premenopausal range and a significant fall in plasma FSH level and symptom score. Bone resorption, assessed by urinary excretion of calcium and hydroxyproline, decreased significantly while plasma alkaline phosphatase activity remained constant. There was a significant fall in plasma calcium and phosphate but the plasma concentrations of PTH, calcitonin and calcitriol and the urinary excretion of cAMP were unchanged. Plasma levels of vitamin D binding protein, albumin and globulin were unaltered, and blood pressure did not rise. These effects were similar to those found in postmenopausal women with oral ethinyloestradiol, 30 micrograms/d, (Selby et al., 1985), apart from those on plasma vitamin D binding protein, total calcitriol, albumin, globulin, tubular reabsorption of phosphate and blood pressure, changes which probably arise from a direct action of oral oestrogen on the liver.

Administration, Cutaneous↗
PubMed1986

Hypercalcaemia due to sarcoidosis corrects with bisphosphonate treatment.

We report a case of sarcoid hypercalcaemia treated with the bisphosphonate, APD [(3-amino-1-hydroxypropylidene)-1,1-bisphosphonate]. Investigations showed that the hypercalcaemia was associated with a high plasma 1,25 dihydroxy vitamin D concentration. A low dietary intake of calcium partially corrected the hypercalcaemia but APD rapidly normalized plasma calcium without reducing the elevated 1,25 dihydroxy vitamin D concentration. The case demonstrates that hypercalcaemia in sarcoidosis results from the effects of 1,25 dihydroxy vitamin D on bone as well as on calcium absorption and that prolonged suppression of the effect on bone occurs with APD treatment.

Calcium↗
PubMed1985

Evaluation of the complement fixation and indirect immunofluorescence tests in the early diagnosis of primary Q fever.

A comparison was made of the performance of the commonly used complement fixation test and the more recently developed indirect immunofluorescence test in the early diagnosis of Q fever. The 303 sera tested were from 181 patients who contracted Q fever during an outbreak in Switzerland in 1983. Specific IgM antibodies were detected by the immunofluorescence test in 53% and 89% of sera obtained during the first and second week respectively after onset of illness. With the complement fixation test, the diagnosis could not be made until the second week of illness. The immunofluorescence test proved to be superior to the complement fixation test in the early detection of Q fever. Not only was it more specific but also faster and simpler to perform, permitting an earlier diagnosis on the basis of results obtained with a single serum specimen.

Antigens, Bacterial↗
PubMed1985

Long term study of the effect of rifampicin and isoniazid on vitamin D metabolism.

Eight patients with tuberculosis were studied before, during and after 9 months treatment with rifampicin and isoniazid to assess the overall effect on vitamin D metabolism. No significant uniform change in either 1,25(OH)2D or 25 OH D nor in any of the other biochemistry measured occurred during the study. It seems unlikely that the combined effects of these drugs causes clinically significant derangement of vitamin D metabolism in patients treated over a 9 month period for tuberculosis.

Adult↗
PubMed1985

Sodium pentosan polysulphate as a polyanionic inhibitor of calcium oxalate crystallization in vitro and in vivo.

Studies in vitro showed that sodium pentosan polysulphate (SPP) is an active inhibitor of calcium oxalate crystal growth and agglomeration and that it acts by increasing the negative zeta potential on the surface of calcium oxalate crystals. Oral administration to human subjects resulted in an increase in the negative zeta potential, which is consistent with an increase in the polyanionic inhibitory activity of urine. SPP may offer a novel approach to the medical management of recurrent calcium oxalate stone disease.

Adult↗
PubMed1985

Early effects of ethinyloestradiol and norethisterone treatment in post-menopausal women on bone resorption and calcium regulating hormones.

The early effects of sex steroid therapy were assessed in 28 normal post-menopausal women, 18 treated with ethinyloestradiol and 10 with norethisterone. There was a reduction in the fasting urinary excretion of both calcium and hydroxyproline with both treatments, indicating reduced bone resorption. This was apparent after 1 week of therapy but became more marked after 3 weeks. These changes were not accompanied by any changes in plasma levels of calcitonin or parathyroid hormone. Patients receiving ethinyloestradiol showed a marked increase in plasma 1,25-dihydroxyvitamin D (1,25-(OH)2D) concentration but this was explicable entirely in terms of increased plasma levels of vitamin D binding protein. There was no change in the free plasma level of 1,25(OH)2D. Patients treated with norethisterone showed no increase in plasma concentrations of 1,25(OH)2D. We conclude that both ethinyloestradiol and norethisterone have a rapid and similar effect in reducing bone resorption. This is not mediated via the plasma levels of the calcium regulating hormones.

Bone Resorption↗
PubMed1985

A prospective trial of the effect of vitamin D supplementation on metacarpal bone loss in elderly women.

The effect on cortical bone loss of treating elderly women with 15,000 IU vitamin D2 weekly was evaluated by sequential radiographic morphometry of the metacarpals. One hundred nine randomly selected women aged 65-74 yr were studied for 2 yr. The women were randomly allocated to control or treated groups taking placebo or vitamin D2 capsules. Hand radiographs and blood samples were obtained at the beginning and end of the trial. Plasma 25-hydroxyvitamin D was measured by radio-competitive protein binding assay. Comparing the treated and control groups, vitamin D treatment significantly raised the plasma 25-hydroxyvitamin D levels (p less than 0.001) and reduced the rate of cortical bone loss (p less than 0.01). The placebo had no measurable effect on the plasma levels.

Aged↗
PubMed1985

Genomic analysis of phase I and II Coxiella burnetii with restriction endonucleases.

Restriction endonuclease-digested DNAs from several isolates of phase I and phase II Coxiella burnetii were compared using agarose gel electrophoresis and soft-laser scanning densitometry. Our results demonstrate that the two phases are, as previously assumed, alternative phases of the same organism. Although the restriction endonuclease digestion revealed genetic differences between clonal isolates of phase I and phase II C. burnetii Nine Mile strain, these differences do not appear to be related to antigenic phase variation. However, analyses of the fragment patterns generated by restriction enzyme digestion suggest potential grouping of the different isolates.

Coxiella↗
PubMed1985

The first human case of domestic Q fever in Sweden.

A case of Q fever in a 56-year-old man is reported. The patient had visited Mallorca six months prior to the present disease. Except for that he had not been outside Sweden for several years, thus being the first known case of Q fever acquired in this country.

Humans↗
PubMed1985

Immunoglobulin responses in acute Q fever.

Knowledge of the development of different classes of antibody during the course of acute Q fever is important to the clinician for interpreting a patient's serological test results. In the present study, the appearance of antibodies to Coxiella burnetii phases I and II was determined for a period of 1 year. A total of 683 sera from 191 patients with symptomatic Q fever were evaluated by the complement fixation and indirect immunofluorescence (immunoglobulins M and G [IgM, IgG]) tests. These patients had contracted acute Q fever in the fall of 1983 during an epidemic that resulted in 415 serologically confirmed cases of Q fever. As demonstrated by the complement fixation test, antibodies to C. burnetii phase II remained elevated throughout the entire study period, whereas antibodies to phase I were barely detectable. Although the immunofluorescence test was more sensitive than the complement fixation test, the specific anti-IgG response to C. burnetii to phases I and II gave the same general antibody profiles as did the complement fixation test. IgM anti-phase I and II titers appeared earlier but disappeared after 10 to 12 weeks. During this period, anti-phase II antibody levels were generally much higher than anti-phase I antibody levels.

Antibodies, Bacterial↗
PubMed1985

A stochastic model of age-related bone loss and fractures.

A stochastic model of age-related bone loss capable of predicting age-specific incidence of fractures has been implemented by Monte Carlo simulation. Each simulation involves aging a large cohort of individuals from 20 to 100 years. Every individual is randomly allocated a particular amount of bone as a young adult, an age of onset of bone loss, and parameter values that determine the subsequent bone loss. Fracture risk is assumed to be zero when the amount of bone is above a global threshold level, increasing progressively as the amount of bone falls below the threshold. From the individual fracture risks, a fracture subpopulation is identified and age-specific incidence evaluated numerically. By adjusting the model parameters, predicted and observed incidences of femoral neck fracture can be closely matched in both sexes by use of a linear function to describe age-related bone loss. For fracture of the distal radius, a close match can be achieved in women by use of an exponential function to describe the bone loss phase. In men, the incidence is independent of age; trauma, rather than the amount of bone in the forearm, appears to be the main determinant of fracture risk.

Adult↗
PubMed1984

Hypomagnesaemia after small bowel resection: treatment with 1 alpha-hydroxylated vitamin D metabolites.

Seven patients with severe neuromuscular symptoms due to hypomagnesaemia together with hypocalcaemia following extensive resection of the small bowel were treated orally with 1 alpha-hydroxylated metabolites of vitamin D and magnesium oxide. There was a rapid response in both plasma calcium and magnesium concentrations. The mean plasma magnesium rose from 0.24 to 0.45 mmol/l with the vitamin D metabolites alone and to 0.81 mmol/l when magnesium oxide was added. The plasma calcium rose from 1.78 to 2.21 mmol/l on vitamin D alone and then remained within the normal range. This was accompanied by a rapid resolution of the neuromuscular symptoms. Such oral treatment is both acceptable to the patient and effective both for acute symptoms and in the long term to maintain plasma magnesium concentrations.

Administration, Oral↗
PubMed1984

When should patients with symptomatic urinary stone disease be evaluated metabolically?

To determine the optimal time at which to assess the urinary risk factors for calcium stone formation, we followed 11 patients after an episode of acute renal colic with sequential 24-hour urine collections, first in the hospital and then at regular intervals after they were discharged from the hospital. The changes that occurred in the urinary risk factors were compared to those of a control group in which samples were collected during the same interval. The in-hospital 24-hour urine volumes were high but decreased gradually to approach the relatively constant volume of the control group by 3 months. The opposite trend occurred with respect to the 24-hour urinary excretion of calcium. There were no significant changes in the 24-hour urinary pH or excretions of oxalate, uric acid and alcian blue precipitable polyanions. The over-all effect was to cause a progressive increase in the probability of stones forming in the patients. The accurate assessment of the urinary risk factors of calcium stone disease requires at least a 3-month delay following acute renal colic. This delay usually will provide sufficient time for the stone to pass and for the patient to return to the normal dietary and fluid intake.

Adult↗
PubMed1984

Calcium malabsorption in elderly women with vertebral fractures: evidence for resistance to the action of vitamin D metabolites on the bowel.

Radio-calcium absorption, plasma 25-hydroxyvitamin D [25-(OH)D] and 1,25-dihydroxyvitamin D [1,25-(OH)2D] concentrations were measured in 19 elderly women with, and 21 without, vertebral fractures, before and after treatment with 25-hydroxyvitamin D3 [25-(OH)D3], to establish whether malabsorption of calcium in elderly women with vertebral fractures has a cause different from that in elderly women without vertebral fractures. Malabsorption of calcium and low plasma 25-(OH)D and 1,25-(OH)2D concentrations were common in both groups of women but there was no significant difference in these variables between the two groups. After treatment with 40 micrograms of 25-(OH)D3 daily for 7 days, there was a significant increase in plasma 25-(OH)D and 1,25-(OH)2D in both groups of women, but radio-calcium absorption increased significantly only in the group without vertebral fractures. Elderly women with vertebral fractures have malabsorption of calcium which is resistant to the action of vitamin D metabolites at concentrations which correct calcium malabsorption in elderly women without vertebral fractures.

25-Hydroxyvitamin D 2↗
PubMed1984

Renal impairment and its effects on calcium metabolism in elderly women.

Investigation of 21 elderly women with a wide range of renal function showed that plasma creatinine concentrations above 100 mumol/l were associated with glomerular filtration rates (GFR) below 50 ml/min. Plasma 1,25-dihydroxyvitamin D concentrations and radio-calcium absorption were directly related to GFR and were low when the GFR was less than 50 ml/min. Plasma parathyroid hormone concentrations were inversely related to GFR and were high when it was below 40 ml/min. In 126 women over the age of 60 admitted to a geriatric assessment ward, plasma creatinine concentrations above 100 mumol/l were found in 73 and we conclude that renal impairment is common in elderly women admitted to hospital and is of sufficient degree to disturb the endocrine control of calcium metabolism seriously.

Aged↗
PubMed1984

Inhibition of calcium oxalate crystallisation by pentosan polysulphate in control subjects and stone formers.

In vitro studies showed that sodium pentosan polysulphate (SPP) is an active inhibitor of calcium oxalate (CaOx) crystal growth and agglomeration and that it acts by increasing the negative zeta potential on the surface of CaOx crystals. Oral administration of SPP to control subjects, recurrent stone formers and patients with primary hyperoxaluria resulted in an overall increase of 8% (P less than 0.01) in the polyanionic inhibition of CaOx crystallisation in urine as measured by the zeta potential. SPP could provide a novel approach to the medical prevention of recurrent CaOx stone disease.

Adult↗