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Biomedical subjects

D MacDonald

Publications and source records attributed to D MacDonald.

At least 19 recordsLinked to original sources
PubMed1992

Serum intact parathyroid hormone levels in elderly Chinese females with hip fracture.

Serum intact parathyroid hormone (PTH), 25 hydroxyvitamin D(25OHD), 1,25 dihydroxyvitamin D (1,25(OH)2D), albumin, and ionized calcium were measured in 61 Chinese female patients with hip fracture and 61 control subjects. Hip fracture patients had low albumin, ionized calcium, and 250HD levels. Serum PTH and 1,25(OH)2D values were not different between the two groups. We conclude that although 250HD level in hip fracture patients is low, there is no evidence of secondary hyperparathyroidism, suggesting that the low 250HD levels may be a secondary phenomenon in response to the fracture.

Aged↗
PubMed1992

Case report: fatal overdose with sustained-release verapamil.

Verapamil is generally a safe and effective drug in the treatment of many vascular disorders. During the past 10 years, a number of serious poisonings have been attributed to verapamil overdose. A relatively new problem is toxicity with the sustained-release form of verapamil. Complications of verapamil overdose can be understood as simply an extension of its pharmacologic activity. Consistently effective therapy remains elusive. Specific calcium channel blocker antidotes are under investigation, but supportive therapy remains the mainstay for serious verapamil overdose.

4-Aminopyridine↗
PubMed1992

Age-related changes in bone density, serum parathyroid hormone, calcium absorption and other indices of bone metabolism in Chinese women.

OBJECTIVE: To study the age-related changes in bone density, serum parathyroid hormone, calcium absorption and other indices of calcium metabolism in Chinese women who habitually have a low calcium intake. DESIGN: Cross-sectional study. SUBJECTS: One hundred and fifty-six healthy Chinese women aged 20-83 years. None were on any medication or vitamin supplements. Subjects over the age of 60 years were all living in a hostel; younger subjects were nurses or subjects attending a family clinic for minor illnesses. MEASUREMENTS: Fasting blood and urine samples were collected for biochemical measurements and calcium absorption was measured using 45Ca by the method of Marshall and Nordin. Bone density was measured by dual energy X-ray densitometry (Norland X R20 X-ray bone densitometer) at the left hip and lumbar spine. Serum parathyroid hormone was measured by a chemiluminometric assay. RESULTS: Plasma ionized calcium concentration, alkaline phosphatase, bicarbonate, plasma creatinine and serum B2 microglobulin were significantly higher in the elderly than in the young, whereas plasma phosphate and the anion gap were higher in the young. Urinary excretion of calcium, phosphate and hydroxyproline were all higher in older women. Plasma parathyroid hormone concentration was positively correlated with age even after taking into account the decline in renal function (as indicated by the rise in B2 microglobulin (r = 0.506, P less than 0.001). Serum concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were not lower in the older women. Fractional calcium absorption from an oral load of radiolabelled calcium was significantly lower in the older women and 37% of the older women were below the 2.5 percentile found in the younger women. Bone density measured by dual energy X-ray densitometry was also significantly lower in the elderly. CONCLUSION: In Chinese women there is an increase in PTH and a decrease in calcium absorption with age in spite of the presence of normal vitamin D metabolites.

Absorption↗
PubMed1992

Interrelationships between urinary sodium, calcium, hydroxyproline and serum PTH in healthy subjects.

The effect of sodium intake on the excretion of calcium, hydroxyproline (OHP) and serum parathyroid hormone (PTH) was examined. When seven healthy males increased their sodium intake by 200 mmol/day, excretion of calcium increased by 1.70 mmol/day and that of OHP by 27%. Serum PTH, however, did not increase significantly. In a cross-sectional study of 334 healthy female subjects there were strong positive correlations between fasting urinary sodium/creatinine (Na/Cr) and calcium/creatinine (Ca/Cr) ratios (r = 0.573) and between Na/Cr and urinary OHP/Cr ratios (r = 0.246). Serum PTH was negatively correlated with Na/Cr ratio (r = -0.161). We conclude that an increase in dietary sodium causes calciuria and an increase in hydroxyproline excretion. The results do not support the hypothesis that this is mediated by PTH.

Adult↗
PubMed1991

Fetal acidosis in labour: a prospective study on the effect of parity.

The effect of parity on intrapartum fetal scalp pH was investigated in 6466 patients in labour with a live fetus who were delivered in 1987. 350 (5.4%) required fetal scalp blood sampling for pH (FBS), 236 primigravidae (10.4%) and 114 multigravidae (2.7%) (P less than 0.001). Fetal acidosis (pH less than 7.20) was detected in 35 patients, 27 primigravidae (11.4%) and 8 multigravidae (7.0%) (P less than 0.001). The incidence of intrapartum acidosis in the 2275 primigravidae and the 4191 multigravidae was 1.2 and 0.2% respectively (P less than 0.001). The two deaths from birth asphyxia and three cases of neonatal seizures occurred in primigravidae. In primigravidae requiring FBS, fetal acidosis was not associated with the use of oxytocin or with increased duration of labour. Neonatal seizures were more common overall in primigravidae than in multigravidae and more common in patients requiring FBS than in those not requiring FBS (P less than 0.05). The higher incidence of FBS, fetal scalp acidosis and neonatal seizures in primigravidae has important implications for intrapartum fetal monitoring.

Acidosis↗
PubMed1991

Assay restriction profiles of three monoclonal antibodies recognizing the G3m(u) allotype. Development of an allotype specific assay.

Three monoclonal antibodies raised against a purified human IgG3 paraprotein were found to exhibit a restriction profile for IgG3/G3m(u) and pan-IgG specificity which was dependent on the assay system. When adapted to an IgG3 subclass capture ELISA, all three McAbs discriminated between paraproteins expressing G3m(u) and antithetical markers G3m(st). One of the antibodies (PNF69C) was selected and conditions were optimised for Gm typing purposes. Using this system G3m(u) could be detected on captured IgG3 derived from human sera. This system may prove useful in the elucidation of Gm allotype profiles.

Animals↗
PubMed1991

Electronic fetal heart monitoring, auscultation, and neonatal outcome.

In a large randomized, controlled study of fetal heart rate monitoring with either continuous electronic fetal heart monitoring or auscultation at specified intervals, only one pattern of deviation in the fetal heart rate correlated significantly with neonatal neurologic examinations at 0 to 48 hours and 72 hours to 1 week: late decelerations in stage 1 and in stage 2. Other variables from labor and delivery, specifically, duration of labor after hospital admission, failure of labor to progress, number of fetal scalp pH values, and presence of meconium were important predictors of neonatal outcome in the regression analyses. The fetal heart rate deviations did contribute significantly to the percent variance accounted for in the regression analyses with neonatal outcomes of Apgar scores at 1 and 5 minutes and serial neonatal neurologic examinations.

Apgar Score↗
PubMed1991

Hospice social work: a search for identity.

This article describes social work's contribution to hospice philosophy and practice, calls attention to the lack of a distinct social work function on hospice teams, and examines various ways to resolve the problem of social work identity in hospice care. Insights from recent peer discussions of hospice social workers tend to support Kulys and Davis's (1986) earlier findings that psychosocial care is provided regularly by hospice team members other than social workers. Options for strengthening the hospice social work role are discussed, including the development of more specific therapeutic techniques and social work leadership in conducting applied research. The importance of maintaining a value-based, critical perspective is stressed.

Aged↗
PubMed1991

The prevention of the maternal manifestations of pre-eclampsia by intensive antihypertensive treatment.

The purpose of the study was to determine if reduction of pregnancy hypertension to normal prevented the clinical maternal manifestations of pre-eclampsia. Thirty-six women with hypertension, but without proteinuria, were allotted at random to a test group of 17 who received intensive treatment, and a control group of 19 who were managed according to routine methods by hospital staff unconnected with the study. The development of proteinuria was chosen as an indicator of pre-eclampsia. Proteinuria developed significantly more often in the control group (in six of the 19 women) than in the test group (in one of the 17 women).

Adult↗
PubMed1990

Erythrocyte sodium fluxes, ouabain binding sites, and Na+,K(+)-ATPase activity in hyperthyroidism.

Erythrocyte sodium pump activity, in contrast to other tissues, is decreased in hyperthyroidism. In order to examine whether the effect of thyroid hormones on erythrocytes is part of a generalized effect on other transport pathways, we measured sodium pump activity, Na+,K(+)-adenosine triphosphatase (ATPase) activity, ouabain binding sites, bumetanide-sensitive sodium potassium cotransport (SPC), sodium lithium countertransport (SLC), and ouabain- and bumetanide-insensitive passive efflux of sodium (sodium "leak") in erythrocytes from 20 healthy subjects and 18 untreated hyperthyroid subjects. Sodium pump activity (ouabain-sensitive sodium efflux rate constant), Na+,K(+)-ATPase activity, and the number of ouabain binding sites were lower and the erythrocyte sodium content was higher in hyperthyroid subjects. The rate constants of erythrocyte SPC (P less than .05), SLC (P less than .001), and sodium "leak" (P less than .05) were also significantly lower in hyperthyroidism. In 11 of the hyperthyroid subjects, sodium flux measurements were repeated after 20 weeks of treatment. Sodium pump activity, the number of ouabain binding sites, and the rate constant for SLC increased. These results suggest that the effect of thyroid hormones on the erythrocyte sodium pump is part of a generalized effect on membrane proteins, rather than a specific effect.

Adult↗
PubMed1990

A comparison of biochemical indices of bone turnover in elderly institutionalized and free-living subjects.

Plasma concentrations of calcium-phosphate, alkaline phosphatase, 25-hydroxyvitamin D (25(OH)D) and albumin, and fasting urinary sodium/creatinine (Na/Cr), calcium/creatinine (Ca/Cr) and hydroxyproline/creatinine (HPr/Cr) were measured in a survey of 208 Chinese elderly subjects living in chronic care institutions, and compared with values from free-living elderly subjects. Plasma parathyroid hormone estimations were also performed on a subpopulation of women living in an institution. Subjects in institutions had higher urinary HPr/Cr ratios in both men and women, as well as higher urinary Ca/Cr ratios in women, suggesting increased bone resorption. These values show significant variation depending on the degree of mobility. Factors which could contribute to the increased bone loss among institutionalized subjects are: reduced physical activity, reduced exposure to sunlight and hence reduced plasma 25(OH)D concentrations, low calcium intake, protein calorie malnutrition and possibly higher sodium intake. Correction of these factors may reduce the risk of fractures among the elderly living in chronic care institutions.

Activities of Daily Living↗
PubMed1990

Interleukin-2 inhibits growth of fibroblasts derived from human bone marrow.

The adherent layer that forms in human bone marrow suspension cultures contains fibroblast colonies which arise from colony-forming cells (CFU-F). We have demonstrated that recombinant interleukin-2 (r-IL2) inhibits growth of CFU-F by preventing their entry into S phase. This inhibition is not mediated by gamma-interferon, nor by T lymphocytes, and can be abrogated by anti-IL2 receptor antibody. r-IL2 may influence haematopoiesis by its effect on bone marrow CFU-F.

Biological Factors↗
PubMed1990

Biochemical predictors for osteoporotic fractures in elderly Chinese--a longitudinal study.

In a longitudinal study of 283 elderly subjects aged 60 years or over living in the community, 9 subjects (7 women and 2 men) developed osteoporosis-related fractures in 30 months. These subjects initially had higher random urinary hydroxyproline/creatinine and calcium/creatinine ratios, and lower plasma 25-hydroxyvitamin D concentrations. These biochemical variables may be useful predictors of osteoporosis-related fractures and may provide a suitable community screening method to identify those most at risk.

25-Hydroxyvitamin D 2↗