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Biomedical subjects

I R Reid

Publications and source records attributed to I R Reid.

158 records · Page 9Linked to original sources
PubMed1986

Bone mineral content in Polynesian and white New Zealand women.

The forearm bone mineral content of Polynesian and European women in New Zealand was measured to assess whether the inter-racial differences found in other populations also occurred in these two groups. The bone mineral content of the nondominant distal radius and ulna was measured by single photon absorptiometry in 123 European and 80 Polynesian women. The mean values were about 20% higher in Polynesians than in Europeans. The reason for this difference in bone mineral content is unknown but the findings do show that high bone density is not confined to African races and that inter-racial differences in bone mineral content may be more common than has been thought hitherto.

Adolescent↗
PubMed1986

The effects of hydrocortisone, parathyroid hormone and the bisphosphonate, APD, on bone resorption in neonatal mouse calvaria.

The effects of hydrocortisone and parathyroid hormone (PTH) upon bone resorption rates in neonatal mouse calvaria have been studied. Bone resorption (measured as 45Ca release) was significantly increased by hydrocortisone (10(-7) M and 10(-6) M) and there was a dose-dependent rise with PTH (0.3-0.9 micrograms/liter). When both PTH 0.3 micrograms/liter and hydrocortisone 10(-8) M were present in the incubating medium, bone resorption did not differ from control, but increasing the hydrocortisone concentration to 10(-7) M augmented 45Ca release by 25% (P less than 0.02) and doubling of the PTH level was associated with a 10% increase (nonsignificant). When both PTH and hydrocortisone were present in the higher concentrations (0.6 micrograms/liter and 10(-7) M, respectively) 45Ca release increased by 39% (P less than 0.005) above that resulting from the lower levels of both hormones (0.3 micrograms/l and 10(-8) M, respectively). (3-Amino-1-hydroxypropylidene)-1,1-bisphosphonate (APD) in concentrations of 3 X 10(-5) M and 10(-4) M, produced inhibition of basal and hydrocortisone/PTH-stimulated bone resorption without evidence of toxicity. These results indicate that hydrocortisone stimulates bone resorption in neonatal mouse calvaria in vitro, in contrast to the results found in fetal rat bone culture systems. PTH has a similar effect, which is additive to that of hydrocortisone and the combined stimulation can be overcome by APD. The possible relevance of these results to the development and prevention of glucocorticoid-induced osteoporosis is discussed.

Animals↗
PubMed1986

The assessment of intestinal calcium absorption using stable strontium.

The availability of currently used methods of measuring intestinal calcium absorption is limited by their expense and complexity. Since this measurement may be important in selecting appropriate therapies for patients with osteoporosis, a simpler procedure is required. This paper describes a test which measures the intestinal absorption of stable strontium. A comparison of this test with the single-isotope radio-calcium absorption test in the same group of patients showed a close correlation between the fractional absorption rates of the two elements (r = 0.93, P less than 0.001). Subjects were correctly categorized as having normal or low absorption in 12 out of 13 cases (92%) and the value in the misclassified subject was at the borderline between normal and low calcium absorption. The convenience, low cost, and freedom from radioactivity of stable strontium make it suitable for routine clinical use and, if necessary, repeated testing. If these early results are confirmed, this test will make the assessment of calcium absorption much more widely available.

Aged↗
PubMed1986

Prophylaxis against vitamin D deficiency in the elderly by regular sunlight exposure.

The effects of regular sunlight exposure on levels of vitamin D metabolites and on other indices of calcium metabolism have been studied in elderly rest-home residents. Fifteen subjects who formerly went outdoors very infrequently were studied over a 4-week period while spending 0, 15 or 30 minutes daily sitting on the rest-home verandah. During this time, levels of 25-hydroxyvitamin D [25(OH)D] rose by 7.4 +/- 1.2 (s.e.m.) microgram/1 in the group spending 30 minutes per day outdoors (P less than 0.005) and there was a smaller but nonsignificant increase in the 15 minutes per day group also. Serum 1,25 (OH)2D levels did not change during the study but serum ionized calcium and alkaline phosphatase showed small, but significant, decreases. Intestinal strontium absorption increased in both treatment groups (P less than 0.05), indicating a similar change in calcium absorption. It is concluded that 30 minutes spent outdoors each day leads to a substantial increase in 25(OH)D levels in elderly subjects and that this has significant effects upon other indices of calcium metabolism. This regimen provides a safe and inexpensive method for the prevention of osteomalacia in frail elderly subjects.

Aged↗
PubMed1986

Calcium supplements in the prevention of steroid-induced osteoporosis.

The long-term use of glucocorticoid drugs frequently results in the development of osteoporosis. To assess the value of calcium supplementation in preventing this loss of bone, the metabolic effects of administering 1 g of elemental calcium/day have been studied in 13 steroid-treated patients. After 2 mo, the fasting urine hydroxyproline-creatinine ratio decreased from 27.1 +/- 2.5 (SEM) to 21.8 +/- 2.4 (p less than 0.001) and there was an increase in fasting urine-calcium excretion (p less than 0.05). Serum alkaline phosphatase and osteocalcin showed no change. We concluded that calcium supplementation suppresses bone resorption without detectable suppression of indices of bone formation and is, therefore, likely to result in increased bone mass. The safety and low cost of calcium make it a very suitable prophylactic agent in glucocorticoid-treated patients.

Adolescent↗
PubMed1986

The acute biochemical effects of four proprietary calcium preparations.

Changes in serum and urine biochemical indices have been studied in ten normal subjects in the four hours following the ingestion of four proprietary calcium supplements. Each was taken in a dose containing 1 gram of elemental calcium. The four preparations were ranked according to the amount of calcium absorbed in the order Spar-Cal and Calcium Sandoz greater than Os-Cal greater than Ossopan. There were no significant differences between the four preparations in the changes in parathyroid hormone (PTH) and urine hydroxyproline levels. For this reason, the four results from each subject were averaged. Following the calcium load there was a reduction in mean PTH from 0.16 +/- 0.01 to 0.10 +/- 0.02 micrograms/l (p less than 0.001) and a decline in urine hydroxyproline/creatinine ratio from 20 +/- 1 to 17 +/- 1 (p less than 0.02), suggesting that bone resorption responds immediately to dietary calcium intake. There was a rise in urine sodium excretion which correlated with the indices of calcium absorption (r = 0.63, p less than 0.01) but not with the sodium content of the calcium preparations. This effect could be important, particularly in elderly patients on borderline sodium intakes.

Administration, Oral↗
PubMed1986

Low serum osteocalcin levels in glucocorticoid-treated asthmatics.

Serum osteocalcin (OC) levels were measured in 19 asthmatic patients receiving long term glucocorticoid therapy and in age- and sex-matched asthmatic patients not receiving this treatment. In the glucocorticoid-treated patients, the mean OC level was approximately 50% less than that in the control group (P less than 0.001), and there was a direct correlation between serum OC and 1,25-dihydroxyvitamin D [1,25-(OH)2D; r = 0.71; P less than 0.001]. Multiple regression analysis in a total of 39 glucocorticoid-treated patients indicated that OC correlated directly to 1,25-(OH)2D and inversely to glucocorticoid dose. There was no correlation between OC and 1,25-(OH)2D in the control group and no significant difference in mean serum 1,25-(OH)2D between the steroid-treated asthmatic patients and the asthmatic control patients. The effect of a 4-day course of oral 1,25-(OH)2D on serum OC was studied in six patients with glucocorticoid excess and six normal subjects. There was a similar percent increase in OC levels in both groups, though the basal concentrations and absolute increases were substantially less in the steroid-treated group. It is likely that the depression of serum OC in glucocorticoid-treated patients results from the reduction in the rate of bone formation induced by these hormones.

Administration, Oral↗
PubMed1984

The chronic and severe forms of eosinophilic meningitis.

Two cases of chronic eosinophilic meningitis (presumed to be due to Angiostrongylus cantonensis) and a third patient with a severe form of this disease are described. Such cases are rare in the published literature. All patients developed their illness in Western Samoa, an area previously thought to be free of the disease. The need to consider eosinophilic meningitis in patients with chronic and severe neurological disease who live in, or have recently come from, endemic areas is emphasised.

Adult↗
PubMed1983

The use of iatrogenic hypothyroidism to treat intractable angina.

An elderly man who had incapacitating angina, despite coronary artery surgery and maximal medical management was deliberately made hypothyroid with radio-iodine. Five years later he was virtually free of chest pain. There is still a limited number of patients in whom this is a useful form of therapy, despite the attendant morbidity of myxoedema.

Aged↗
PubMedDate not supplied

Intestinal blood flow in the dog measured by indicator fractionation without tissue samples.

1. A modification of Sapirstein's indicator fractionation technique for measurement of intestinal blood flow has been studied and evaluated in the dog. 2. The concentration of 42K within the intestinal wall was measured simultaneously by a tissue assay procedure and by use of a miniature Geiger-Müller tube within the intestinal lumen. Both methods gave similar results under a wide variety of conditions. 3. Isotope measurement by the Geiger-Müller tube technique obviates the need for tissue samples to be taken and would permit repeat measurements of intestinal blood flow in the same animal.

Animals↗
PubMedDate not supplied

Relation between increase in length of hip axis in older women between 1950s and 1990s and increase in age specific rates of hip fracture.

OBJECTIVE: To determine whether length of hip axis in elderly women has increased over the past 40 years and, if so, whether the increase may have contributed to the increase in the age adjusted rate of hip fractures during those years. DESIGN: Retrospective assessment of anteroposterior x ray films of the pelvis. SETTING: Radiology department of a rheumatology hospital, New Zealand. PATIENTS: Two cohorts of women aged > 60 (mean 70) who were x rayed on the same apparatus in either the 1950s or the 1990s. MAIN OUTCOME: Length of hip axis (distance from the medial aspect of the pelvis to the lateral aspect of the femur along the axis of the femoral neck), length of femoral neck (length of hip axis excluding the femoral head and more medial structures), and width of femoral neck (see figure). RESULTS: Both the mean length of the hip axis and the mean length of the femoral neck were significantly greater in the women whose x ray films were taken in the 1990s than in those in the 1950s (124.0 mm (SE 1) v 130.5 (1), P = 0.0002; 79.4 (1) v 84.9 (1), P < 0.0001, respectively). The width of the femoral neck did not change, and the lengths expressed as ratios to width were greater in the more recent x ray films, indicating that these findings are not due to an unrecognised change in radiographic technique. CONCLUSIONS: An increase in the length of the hip axis in elderly women in New Zealand during the past 40 years has occurred which is large enough to account for the increase in the age adjusted rate of hip fractures during those years.

Aged↗