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Biomedical subjects

K Boddy

Publications and source records attributed to K Boddy.

At least 19 recordsLinked to original sources

Intercomparison of whole-body counters using a multinuclide calibration phantom.

Whole-body counters in the UK have been compared using a multinuclide anthropomorphic phantom. A standard Bush phantom was modified by inserting channels into the long axis of each section. Radionuclide sources sealed in a urea-formaldehyde polymer were then inserted into the channels to simulate distributions of radioactivity in a human. The phantom was taken to 10 whole-body counters in the UK and estimates of 134Cs, 137Cs and 40K were obtained both separately and as mixtures. Results showed close agreement between the median estimates and the known activities. The technique also allowed diagnosis of particular problems in calibration for several of the counters.

Calibration

Autoregressive spectral estimation of fetal breathing movement.

Fetal breathing movement (FBM) in utero may be an indicator of fetal health. This paper provides a second-by-second estimate of FBM rate. In the absence of a statistical model for the fetal breathing movement, block data structured autoregressive spectral estimation is used. The optimum tapered Burg algorithm provides a minimum variance breathing rate estimate from a short block of data. The data were recorded using a PVDF (PolyVinyliDeneFluoride) transducer which picks up maternal abdominal wall movements. A peak tracking algorithm is used to extract the fetal breathing rate. Results from these signals are presented in graphical form. Further analysis of the fetal breathing rate has revealed periodicities, similar to that observed in the fetal heart rate.

Algorithms

Fasting hyperinsulinemic hypoglycemia after ritodrine therapy for premature labor.

A 26-year-old woman with a triplet pregnancy was treated prophylactically with ritodrine beginning at 15 weeks' gestation. At 32 weeks, she was admitted in preterm labor, and over the next 12 days received high-dose oral or intravenous ritodrine. Three female infants were delivered by cesarean section after spontaneous rupture of the membranes. Postoperatively, she developed profound hypoglycemia with inappropriately high insulin levels. Maternal hypoglycemia after ritodrine therapy in pregnancy has not been reported previously. We discuss possible mechanisms.

Adult

Body elemental composition, with particular reference to total and exchangeable sodium and potassium and total chlorine, in untreated and treated primary hyperaldosteronism.

The whole body content of sodium, potassium, chlorine, calcium, phosphorus and nitrogen was measured by neutron activation analysis in 13 patients with untreated primary hyperaldosteronism (Conn's syndrome; aldosterone-secreting adenoma). Concurrently, exchangeable sodium and potassium were estimated by isotope dilution. Results were compared with values in the same patients during treatment with potassium-conserving diuretics and again after removal of the adenoma; and also with those in a series of 30 patients having untreated essential hypertension. Both total body and exchangeable sodium were high in Conn's syndrome before treatment and were reduced by spironolactone or amiloride and by subsequent surgery. There was no evidence of alteration in the proportion of non-exchangeable sodium in this disease, in contrast to earlier reports. Total body and exchangeable potassium were low in untreated Conn's syndrome and increased to normal after therapy: the proportion of non-exchangeable potassium was similar before and after treatment, and also similar to that in essential hypertension. Total body chlorine was increased before treatment in Conn's syndrome and returned to normal with therapy; body calcium, phosphorus and nitrogen were normal throughout.

Adult

Whole-body elemental composition in patients with renal failure and after transplantation studied using total-body neutron-activation analysis.

Whole body elemental composition in seventy-five patients with either renal failure or a kidney transplant was measured by neutron-activation analysis and whole-body counting. Comparison was made with expected normal values and with a control group; between undialysed, dialysed and transplanted patients; and between those receiving dialysis treatment for various periods. A frequent finding was low body calcium, reflecting the prevalence of renal osteodystrophy. Sodium and chlorine were increased in undialysed patients, a consequence of their renal disease. Patients with transplanted kidneys had reduced amounts of most elements, indicating decreased lean body mass, but increased body weight, probably due to excess fat.

Body Composition

Fetal breathing: its physiologic and clinical implications.

The respiratory movements the human fetus makes in utero can be detected and used as a valuable aid in determining fetal well-being. Their presence or absence, amplitude, and duration can all provide important information. Their absence, however, does not carry a poor prognosis unless other indices of fetal status, such as the nonstress test and oxytocin-challenge contraction-stress test, are also abnormal at the same time.

Animals

Whole body elemental composition during drug treatment of rheumatoid arthritis: a preliminary study.

Thirty-two female patients with rheumatoid arthritis were divided into 3 groups and treated for 6 months with prednisolone, depot tetracosactrin, or indomethacin. Their whole body content of calcium, phosphorus, and nitrogen was measured before and after 3 and 6 months' treatment by in-vivo neutron activation analysis. No significant changes in these body elements were observed as a result of the treatments. The average amounts of calcium, phosphorus, and nitrogen were lower than normal in these patients, a finding consistent with the frequent observation of osteoporosis and muscle wasting in rheumatoid arthritis.

Adult

Concurrent estimation of total body and exchangeable body sodium in hypertension.

1. Total-body neutron-activation analysis in vivo was carried out in 11 hypertensive subjects to measure simultaneously the total body content of sodium, chlorine, calcium, phosphorus and nitrogen. 2. There was a highly significant correlation between total body sodium measured by activation analysis and total exchangeable sodium measured by a standard isotope-dilution technique (r = 0.92, P less than 0.001). Exchangeable sodium averaged 80.3% of total body sodium. 3. The measured values of chlorine, calcium, phosphorus and nitrogen were similar to those for healthy subjects reported by others. 4. Activation analysis in vivo appears promising as an additional tool for investigating sodium metabolism in hypertension, as it is the only method available for determining the total body content of this element. The radiation dose (1 rem) is sufficiently low to permit repeated measurements in the same subject.

Adult