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Biomedical subjects

J E Harrison

Publications and source records attributed to J E Harrison.

171 records · Page 10Linked to original sources
PubMed1966

A preliminary study of human calcium metabolism using long-term whole body tracer measurements.

Long-term bone calcium metabolism was measured using a whole body counter apparatus and the radioisotopes calcium-47 and strontium-85. Strontium was given with calcium in a single intravenous injection in order to estimate long-term retention of calcium. Calcium-47, with a short radio-active half-life, was measured directly for 20 days, and then indirectly from strontium retention for periods up to 200 days.The standard parameters of calcium transport were measured and, as well, a new parameter, calcium accretion to the fixed bone pool. These studies were carried out on 13 subjects, six of whom were selected "normals" and seven were patients with osteoporosis. Calcium accretion to the fixed bone pool, the new index of bone formation, varied from 100 to 210 mg. of calcium daily in normal subjects and from 70 to 340 mg./day in patients with osteoporosis. These values are one-third of those for the accretion to the total bone pool, the previously reported bone formation rate.

Bone and Bones↗
PubMedDate not supplied

Studies of cadmium uptake in bone and its environmental distribution.

Rat experiments indicate that oral ingestion of cadmium through drinking water leads to an accumulation of cadmium in bone, in addition to liver and kidney. After five weeks of cadmium intake in drinking water (50 to 100 mg/L), the bone cadmium levels increased in proportion to the intake concentration. Bone and kidney histology showed no signs of bone or kidney damage up to 5 wk of cadmium ingestion. Cadmium accumulation in bone was a primary phenomenon and not secondary to renal failure. In addition, cadmium levels have been estimated in a variety of sources, e.g., foodstuff, fertilizer, and sewage sludge, using neutron and proton activation analyses and atomic absorption spectrophotometry. Cadmium levels of Canadian foods are in the range of 0.002-0.07 mg/kg, and soils are in the range of 0.55 to 1.72 mg/kg. Fertilizers contain cadmium from 0.3 to 1.25 mg/kg, whereas sewage sludge contains up to 122 mg/kg.

Animals↗
PubMedDate not supplied

Recent developments in in vivo neutron activation analysis facilities.

Two new facilities for in vivo activation analysis of patients have been designed, developed, and constructed at Toronto General Hospital. One of these is for the determination of body calcium for the diagnosis of osteoporosis and other diseases associated with bone loss. The other is for the measurement of total body nitrogen for the determination of protein status. These facilities replace old university facilities and take into account the comfort and management of patients. In addition, in the case of the calcium facility, the precision of the measurements has been improved because of larger detector volume and increased neutron source strength. Both the facilities are now in routine hospital clinical use.

Bone Density↗
PubMedDate not supplied

A minimum component AM transmitter to monitor electronic brain stimulation.

Construction of a light weight AM transmitter which can be used to monitor implanted electronic brain stimulators is described. The unit can operate continuously for 40 hours on a single battery and can easily be carried by a small laboratory animal. The range of the unit is limited to approximately 1 meter and the transmitted signal can be detected by a standard AM broadcast band receiver. The unit is simple to construct, inexpensive, and reliable in performance.

Animals↗
PubMedDate not supplied

Bone mineral measurements of the central skeleton by in vivo neutron activation analysis for routine investigation os osteopenia.

In vivo neutron activation analysis has been used to measure bone mineral content in the central skeleton where osteoporotic fractures occur. To be of diagnostic value, the results must be normalized for body size. From data obtained from 74 healthy children and adults up to 55 years of age, we have found that the calcium in the central skeleton is approximately proportional to the cube of the subject's height. The correlation for the adults alone has an r value of 0.81. When data from both adults and children are used, r = 0.95. The validity of this cubic height relationship to the Ca concentration measurements has been further substantiated by studies on rats. The total femur calcium content of 110 rats from weanling to 25 weeks of age was proportional to the overall femur (length) 3.6 (or (length)2.6 per unit length) with r = 0.99. When the level of Ca content is related to data on normal subjects of the same body size (giving the Calcium Bone Index or CaBI) a good separation is obtained between normal volunteers and osteoporotic subjects. Volunteers who were 20 to 55 years of age had CABI 1.0 "/- .12 (SD) while osteoporotics had CaBI 0.69 +/- .10 (SD). When the calcium content as determined by in vivo activation analysis is expressed as a CaBI, it provides a powerful tool for the diagnosis of osteopenia. We suggest that all bone measurements, including peripheral ones, be normalized for body size in order to increase their diagnostic value.

Activation Analysis↗
PubMedDate not supplied

Changes in body protein, body potassium, and lean body mass during total parenteral nutrition.

Lean body mass by anthropometry (AMLBM), total body potassium (TBK), and total body nitrogen (TBN) by prompt gamma analysis, are reported in 38 malnourished patients during total parenteral nutrition. Over long periods (greater than 2 months) TBN increased 32% while AMLBM and TBK rose only by 9.2 and 9.5%, respectively. Changes in AMLBM and in K were significantly correlated, but changes in nitrogen were not correlated with either. From short-term studies, the same conclusions can be obtained; although there are changes in lean body mass and in potassium, there is no correlation with such changes in nitrogen. With repletion, changes in body protein are not necessarily related to changes in AMLBM or to TBK: the latter two reflecting total and intracellular water, respectively, but not protein content.

Anthropometry↗