PubMed Health⌕ Search

Biomedical subjects

J Reeve

Publications and source records attributed to J Reeve.

At least 217 records · Page 12Linked to original sources
PubMed1980

The reproducibility of double-isotope deconvolution measurements of intestinal calcium absorption.

1. Radiocalcium absorption was measured in duplicate in 10 subjects by the double-isotope method, with calcium as the oral carrier (2.5 mmol). Analysis of variance gave 95% confidence limits for a single measurement of fractional absorption and maximum absorption rate in a given individual of +/- 16.5% of administered dose and +/- 18.2% of dose/h respectively. 2. The size of these within individual variations suggests that alterations in the rate of calcium absorption may contribute to the week-to-week stabilization of some other controlled variable, such as plasma concentration of calcium. 3. In six of the subjects, calcium absorption was also measured with calcium loads at concentrations of 0.5, 5.0 and 20 mmol. Significant falls in fractional absorption, maximum absorption rate and mean transfer rate occurred as the load increased, together with a rise in mean transit time. Although between-individual differences at a given load were considerable, given a single-test result with a known carrier load, it is possible to predict quite accurately the results which would be obtained if a different carrier load were to be given.

Analysis of Variance↗
PubMed1980

Effect of salicylates and phenobarbital on hepatic glutathione in the rat.

Phenobarbital and salicylates were shown to have opposite effects on hepatic glutathione. Phenobarbital increased glutathione concentration by approximately 20 to 30%. This increase occurred within 48 hr and could be attributed almost exclusively to an increase in bound glutathione. No changes in ATP, substrate amino acids for glutathione synthesis or the level of gamma-glutamylcysteine synthetase, the rate limiting enzymatic step in glutathione synthesis, were found with phenobarbital. Phenobarbital, which induces hepatic proteins that bind glutathione, increased bound glutathione but did not affect unbound glutathione. Therefore, the concentration of the latter probably regulates glutathione synthesis. Salicylates (aspirin and sodium salicylate) were found to deplete hepatic glutathione in both saline- and phenobarbital-treated rats. Maximum depletion (approximately 40%) was seen 4 to 6 hr after salicylate administration and returned toward the control level by 12 hr. The salicylate effect was not related to a change in gamma-glutamylcysteine synthetase, gamma-glutamyl transpeptidase or the concentrations of free hepatic glycine, glutamate, cysteine and methionine. An increase in concentration of glutathione both in vivo in plasma from salicylate-treated rats and in vitro in buffer from the incubation of liver slices with salicylate suggests that glutathione leakage from hepatocytes is an important factor in salicylate-induced hepatic glutathione depletion.

Amino Acids↗
PubMed1979

A comparison of chromium sesquioxide and [51Cr]chromic chloride as inert markers in calcium balance studies.

1. Chromium sesquioxide (Cr2O3; 1.5 g/day) and [51Cr]chromic chloride [51CrCl3 (0.3 muCi/day)] were compared as continuously administered non-absorbed markers for the correction of faecal recoveries in 14 calcium balance studies each lasting at least 18 days. 2. The mean recoveries of each, 98.4% for Cr2O3 and 101.9% for 51CrCl3, were not significantly different from 100%. 3. The two markers reduced the uncertainity in a typical 3 x 6 day calcium balance study to a similar extent (SD = 1.4 mmol/day for Cr2O3 and SD = 1.5 mmol/day for 51CrCl3. 4. 51CrCl3 is a convenient and satisfactorily alternative to Cr2O3 when the laboratory hazards associated with estimating the latter cannot easily be eliminated.

Calcium↗
PubMed1979

Fractured neck of femur in the elderly: an attempt to identify patients at risk.

1. During a 15-month period, 110 elderly patients admitted with fractured neck of femur were studied in comparison with 72 elderly control patients undergoing elective surgery admitted over the same period to the same orthopaedic wards. 2. A striking finding was the marked similarity of all variables measured in the fracture and control groups. The principal differences between the two populations were that the fracture patients had a lower mean forearm bone mineral content, and that their serum concentrations of albumin, globulin and phosphate were reduced. 3. Neither measurements of radioisotopic calcium absorption, nor those of the serum concentrations of calcium, 25-hydroxy-vitamin D3 nor alkaline phosphatase provided satisfactory discrimination between the groups. 4. Several indices were devised, based on linear combinations of the test results obtained, in an attempt to predict the liability to future fractures of patients being considered for prophylactic therapy with oestrogens or other drugs. However, further work is required to define an index of improved predictive power and to evaluate it prospectively.

Aged↗
PubMed1978

Skeletal blood flow in Paget's disease of bone and its response to calcitonin therapy.

1. Blood flow to the skeleton was measured by the 18F clearance method of Wooton, Reeve & Veall (1976) in 24 patients with untreated Paget's disease. In every patient but one, resting skeletal blood flow was increased. There was a significant positive correlation between skeletal blood flow and serum alkaline phosphatase and between skeletal blood flow and urinary total hydroxyproline excretion. 2. Fourteen patients were re-studied after they had received short-term (7 days or less) or long-term (7 weeks or more) calcitonin. Skeletal blood flow, alkaline phosphatase and urinary hydroxy-proline excretion fell towards normal in every case. There was some evidence from the short-term studies that calcitonin produced a more rapid fall in skeletal blood flow than in alkaline phosphatase. 3. Glomerular filtration rate appeared to increase transiently in response to calcitonin.

Alkaline Phosphatase↗
PubMed1978

Abnormalities of renal transport of sodium o-[131I]iodohippurate (Hippuran) in essential hypertension.

1. Renal function has been studied in 312 hypertensive patients by quantitative renography with sodium o-[131I]iodohippurate (131I-labelled Hippuran) and estimation of overall effective renal plasma flow. In 59% of the patients the results were normal. 2. Severe hypertension was associated not only with reduced effective renal plasma flow but also a characteristic abnormality of Hippuran transport in 10% of the patients in which there was a wider than normal variation in transit times of Hippuran through the kidney, which may reflect non-uniformity of reabsorption of filtrate by different groups of nephrons. 3. Plasma renin activity was higher in a group of 14 patients with multimodal transit time spectra than in a matched hypertensive control group, with very substantial overlap between the two groups. 4. The renographic abnormality was usually reversed by treatment.

Blood Flow Velocity↗
PubMed1978

The turnover time of calcium in the exchangeable pools of bone in man and the long-term effect of a parathyroid hormone fragment.

(1) A non-compartmental method is described for analysing the kinetics of the exchange of calcium between the bloodstream and the exchangeable bone pools. (2) This method has been applied to studies on osteoporotic patients treated with low doses of an active fragment of human parathyroid hormone. The data of Phang et al. (1969), who studied the effects of dietary calcium peturbation on normal volunteers, were also analysed. (3) It was found that in response to chronic PTH treatment the transit time of calcium in the exchangeable pools decreased. This could not be explained by the observed changes in the calcium accretion rate to the fixed bone pools, and it was necessary to postulate an alteration in the ratio of the rate constants governing the interchange of calcium between bloodstream and exchangeable pools. (4) The changes in the behaviour of the exchangeable pools in response to dietary perturbation could not be explained by the postulated increase in endogenous PTH secretion rate in response to dietary calcium restriction.

Bone and Bones↗
PubMed1978

Studies in chronic lymphocytic leukaemia. The kinetics of 51Cr-labelled lymphocytes.

1. 9 Studies of lymphocyte transport are reported in which the 51Cr labelling technique of Hersey (1971) was employed on 8 patients with chronic lymphocytic leukaemia (CLL) and 1 with lymphosarcoma. 2. A new approach to the analysis of the data was formulated employing the principles of impulse analysis. This allowed the quantitation of cell transport between various locations making the minimum number of assumptions. It was also possible to take account of the principal defect of this label, its tendency to elute from live cells. 3. In spite of marked lymphocytosis, numbers of cells moving between those tissues whose lymphocytes exchange relatively slowly and the bloodstream was found to be normal. The blood and lymph nodes may therefore accumulate lymphocytes in response to a transport defect which hinders the progress of these cells from one pool to another. 4. The finding that CLL lymphocytes fluxes are normal in certain locations casts doubt on the hypothesis that lymphocyte proliferation is uncontrolled in this disease. An alternative possibility is that cell proliferation is regulated so as to maintain these fluxes within the normal range.

Aged↗