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Biomedical subjects

J G Roberts

Publications and source records attributed to J G Roberts.

At least 73 records · Page 4Linked to original sources

Serum alpha-1-acid glycoprotein as an index of dissemination in breast cancer.

Assay of the serum alpha-1-acid glycoprotein (SAGP) produced by the liver in response to many disease states is shown to reflect prognosis and monitor progress in patients with early, recurrent and disseminated breast cancer. Eighteen of 26 patients with localized breast cancer and positive bone scans had elevated SAGP when first seen, but within 5 months of treatment 5 further patients with positive bone scans developed an elevated SAGP. Furthermore, an initially abnormal SAGP level became normal within 5 months in 5 of 6 patients with negative bone scans. While elevated SAGP in breast cancer correlates with positive bone scans, a series of normal values may indicate patients without early haematogenous dissemination of their disease.

Bone Neoplasms↗

Photon scattering measurement of calcaneal bone density: result of in vivo cross-sectional studies.

The density of trabecular bone in the os calcis has been measured in 321 subjects using a gamma ray scattering technique. In normal subjects it was shown that density could be predicted from body weight and age with a standard error of 5.6%. It was also shown that the dependence of density upon weight and age was the same for both sexes. When the os calcis had been subjected to a greater than normal mechanical stress by either increased physical activity or excessive body weight, trabecular bone density was increased. Density was measured in 128 patients in whom the incidence of skeletal demineralization was expected to be greater than that in control subjects. Some significant reductions in density were observed. It is projected that density measurements might be of value in those situations where, in response to metabolic stress, the rate of loss of mineral from trabecular bone is greater than that from cortical bone.

Adult↗

[CO2 "wash-out" : a factor contributing to increase myocardial performance in the face of hypoxia (author's transl)].

The cardiovascular system of the anaesthetized dog has been used as an experimental model for studying the mechanisms of the haemodynamic responses to hypoxia. Together with aortic and left circumflex coronary artery blood flow (electromagnetic flow transducers), aortic and left ventricular pressures have been recorded and blood has been sampled from the aorta and the coronary sinus (PO2, PCO2, pH). During short periods of hypoxia an improvement of myocardial performance has been observed both before and after administration of a beta-adrenergic receptor blocker and a marked reduction of coronary sinus PCO2 has been noted. When hypoxia was caused by a mixture of nitrogen (95%) and CO2 (5%) an improvement of performance was observed only before administration of the beta-blocker. The slope of the relationship between PCSCO2 and cardiac performance was found to be similar before and after administration of the beta-blocker and also similar to that observed in studies of the response of the isolated heart muscle to acute hypocapnia. Besides beta-adrenergic receptor stimulation, a reduction of coronary sinus PCO2 (CO2 wash-out due to an increase of coronary blood flow) could be a factor contributing to the maintenance of myocardial performance in the face of hypoxia.

Animals↗