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Biomedical subjects

A Stewart

Publications and source records attributed to A Stewart.

At least 397 records · Page 22Linked to original sources
PubMedDate not supplied

Mechanisms of hypercalcemia in patients with head and neck cancer.

Hypercalcemia associated with head and neck malignancy is not an uncommon occurrence; its causes are multiple. Eight hypercalcemic patients with head and neck malignancy were studied. Serum calcium, serum phosphorus, tubular phosphorus threshold, fasting calcium excretion, plasma 1,25-dihydroxyvitamin D, nephrogenous cyclic adenosine monophosphate (AMP), and immunoreactive parathyroid hormone were measured. Excessive dietary calcium administration in the form of an oral hyperalimentation preparation appeared to be the cause of hypercalcemia in 2 patients. Six patients demonstrated humorally mediated hypercalcemia. These patients resembled patients with primary hyperparathyroidism in having elevated nephrogenous cyclic AMP excretion and reduced proximal tubular phosphorus reabsorption, but they differed from patients with primary hyperparathyroidism by having normal levels of immunoreactive parathyroid hormone, markedly increased fasting calcium excretion, and strikingly reduced mean plasma levels of 1,25-dihydroxyvitamin D. These data strongly suggest that the humoral factor responsible for hypercalcemia in patients with head and neck cancer is not parathyroid hormone, and that patients with hyperparathyroidism can now be distinguished with confidence from those with malignancy-associated hypercalcemia.

Adult↗
PubMedDate not supplied

Confronting actual practice with practice guidelines in oncology.

Improving health care quality requires the availability of data to identify and eliminate unnecessary variations in the care process. Variations can be caused by an ineffective implementation of research findings or by obstacles to the translation of research into clinical practice. The analysis of current patterns of care by the use of routine data from electronic patient records or clinical registries may help highlight these deficiencies in actual care. The growing infrastructure of information technologies and the knowledge about clinically relevant variations of routine practice may help us understand the mechanisms that are impeding the translation of research into practice. There is a need to scrutinize these variations of practice and the barriers to guideline implementation. We think that an understanding and open discussion of such reasons may help, to continuously improve the quality of patient care. This process facilitates efforts and strategies to implement evidence-based medicine in the daily routine.

Data Collection↗
PubMedDate not supplied

Detecting the health risks of radiation.

Radiation can cause both non-stochastic (cell-killing) effects, leading to burns, epilation, immune system damage and lens opacities, and mutational or stochastic effects due to low dose damage to single cells. If the latter are followed by clone formation or fertilization, the mutants are not recognized by the immune system, and there is no competing cause of death, cancer or leukaemia can result. These effects did not become public knowledge until after the A-bombings of Hiroshima and Nagasaki. Subsequent analysis of the data on A-bomb survivors suggests, contrary to official views, that the immune system has a complex role in the aetiology of cancer and leukaemia, and that the A-bomb survivors were unusually resistant to the harmful effects of the bombings. These findings require the re-evaluation of the effects of low-level radiation, which has increased with the growth of the nuclear industry, both civil and military.

Adolescent↗