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Biomedical subjects

A Duncan

Publications and source records attributed to A Duncan.

At least 109 records · Page 6Linked to original sources
PubMed1992

Should mono- or poly-unsaturated fats replace saturated fat in the diet?

The effects of diets differing in saturated, monounsaturated and polyunsaturated fatty acid composition (SAFA, MUFA and PUFA, respectively) on plasma lipoproteins and factor VIIc were investigated in 28 middle-aged men and women with mild to moderate hyperlipidaemia. The subjects were stabilized on a diet with a total fat content fairly typical of New Zealand, containing approximately 40% energy as fat, before entering a randomized cross-over trial of diets high in PUFA (20% energy; SAFA and MUFA 10% each) or a high MUFA diet (20% energy; SAFA and PUFA 10% each). After 6-week periods on each diet the subjects returned to a high SAFA diet. Body weight and blood pressure remained unchanged during the study. Total and LDL cholesterol, HDL cholesterol and the HDL2 subfraction were significantly lower on both the MUFA and the PUFA diet than on SAFA. However, there were no statistically significant differences in lipoprotein concentrations on the MUFA and PUFA diet. Factor VIIc concentrations were similar on the three diets. The proportion of PUFA in a MUFA diet appears to be a major determinant of the relative lipoprotein response to such a diet. In order to avoid a reduction in HDL-C when replacing SAFA with MUFA it may be necessary to ensure that PUFA does not provide more than about 8% total energy. Thus careful planning is needed to identify the most appropriate foods to replace those rich in SAFA in diets designed to reduce the lipoprotein-mediated risk of coronary heart disease.

Aged↗
PubMed1991

Malignant angioendotheliomatosis presenting as disseminated intravascular coagulopathy.

Disseminated intravascular coagulopathy (DIC) occurred in a patient with hemolytic anemia and anasarca. Skin and muscle biopsy showed intravascular lymphomatosis (malignant angioendotheliomatosis). Combination chemotherapy resulted in resolution of the DIC and anasarca. After an unmaintained 8-month clinical remission, the patient had central nervous system relapse and died. Malignant angioendotheliomatosis is a rare disorder that should be considered among the occult causes of DIC.

Aged↗
PubMed1991

Blood lipid levels in New Zealand.

OBJECTIVES: the study aimed to determine age and gender specific levels of lipids and lipoproteins in New Zealanders. Participants were randomly selected from 20 general electoral roles, and from a sample of 15-18 year olds. METHODS: plasma cholesterol, LDL cholesterol, HDL cholesterol and triglyceride levels were measured in 2941 men and women aged 15-99 years. RESULTS: mean (SD) plasma cholesterol was 6.0 (1.3) mmol/L in men and 6.1 (1.3) mmol/L in women. There was a marked variation in total cholesterol and calculated LDL cholesterol with age, and the pattern was different in men and women. There was also a considerable regional variation; levels tending to increase from north to south. Overall mean cholesterol levels adjusted for age and geographical distribution were 5.8 and 6.0 mmol/L for men and women respectively. CONCLUSION: the fact that approximately a third of the adult population in New Zealand under 65 years have cholesterol levels greater than 6.5 mmol/L indicates the need for effective diet and lifestyle changes to reduce the high rates of CHD.

Adolescent↗
PubMed1991

Therapy of the Kasabach-Merritt syndrome with cryoprecipitate plus intra-arterial thrombin and aminocaproic acid.

A patient with the Kasabach-Merritt syndrome with disseminated intravascular coagulopathy and congestive heart failure due to a giant hepatic cavernous hemangioma achieved thrombosis of his tumor with a combination of cryoprecipitate plus intra-arterial thrombin and epsilon aminocaproic acid. This was documented by an absence of Indium 111-labelled platelet sequestration, marked decrease in thrombin:antithrombin complex generation, and normalization of platelet count and fibrinogen. Interventional angiography with aminocaproic acid and thrombin is advocated in patients whose tumors are amenable to such an approach so as to avoid a systemic antifibrinolytic state.

Aged↗
PubMed1991

Osteoclast growth factor activity in medium conditioned by fetal rat bones.

The presence and biological activity of an Osteoclast Growth Factor (OGF) was investigated in serum-free medium conditioned by periostless fetal rat calvaria in culture. OGF activity was assessed using in vitro systems of fetal rat long bones and adult rat bone marrow cells. Rat calvaria conditioned medium (RCCM) increased the number of osteoclasts in the long bone cultures, partly due to stimulation of progenitor proliferation. RCCM did not exert a direct bone-resorbing activity (45Calcium release assay) on the pre-existing osteoclasts residing in the long bones, but stimulated bone resorption in long term cultures, apparently in an indirect manner by enhancing the number of osteoclasts. In cultures of bone marrow cells isolated from adult rats, RCCM markedly stimulated the formation of mononuclear cells which were positively stained for tartrate-resistant acid phosphatase (TRAP). The osteoclastic nature of the cells was confirmed by specific labeling with 125I-calcitonin. Formation of the TRAP-positive cells was significantly inhibited by salmon calcitonin. CM from fetal rat skin cultures did not display a significant OGF activity. Furthermore, unlike the bone marrow cells, peritoneal macrophages did not respond to RCCM and remained devoid of TRAP activity. Neutralization experiments with a specific antibody to GM-CSF indicated that OGF activity in the RCCM could not be ascribed to this hemopoietic growth factor. Secretion of OGF activity was mainly dependent on protein synthesis as addition of cycloheximide to the calvaria cultures significantly inhibited the secretion of OGF into the medium. G3000 HPLC fractionation of RCCM revealed two major OGF peaks with Mr 14,000 and 70,000. Two subsequent reverse-phase HPLC steps using the lower Mr OGF fraction led to a highly purified OGF fraction. The results of this study further provide evidence that bone tissue produces factor(s) which specifically govern the process of osteoclast development, thus providing information about one of the mechanisms controlling bone resorption.

Acid Phosphatase↗
PubMed1991

The role of magnetic resonance imaging in cystic fibrosis.

Magnetic resonance imaging (MRI) of the chest was performed on eight patients with known cystic fibrosis. Comparison was made with the findings on plain chest radiographs. MRI shows a greater extent of disease than that predicted by the chest films alone and clearly demonstrates peribronchial thickening and mucoid impacted bronchi. It also distinguishes between hilar lymphadenopathy and enlarged proximal pulmonary vessels as the cause of prominent hilar shadows without the need for contrast injection.

Adolescent↗
PubMed1991

Evaluation of urinary hydroxypyridinium crosslink measurements as resorption markers in metabolic bone diseases.

Analyses of the urinary concentration relative to creatinine of the collagen crosslinks, pyridinoline (Pyd) and deoxy-pyridinoline (Dpd) were made in 47 patients with metabolic bone diseases to assess the validity of these assays as indicators of bone resorption. The mean values for patients with Paget's disease of bone, primary hyperparathyroidism and osteomalacia were significantly higher (P less than 0.001) than those for age-matched healthy individuals. During treatment of Paget's disease with bisphosphonates, there was a steady decline in the urinary concentration of the crosslinks to the normal range; this change occurred earlier than for serum alkaline phosphatase. There were significant correlations (P less than 0.01) between the concentrations of both crosslinks and the corresponding values for hydroxyproline. At lower crosslink concentrations, however, these relationships were less marked due to large variations in hydroxyproline values. The results show that measurements of urinary Pyd and Dpd provide clinically applicable indices of bone resorption that are more specific than other markers.

Aged↗
PubMed1991

Increased intestinal permeability in ankylosing spondylitis--primary lesion or drug effect?

We have found increased small intestinal permeability to 51Cr-ethylenediaminetetra acetate in patients with ankylosing spondylitis compared with controls. There is no significant difference between patients with ankylosing spondylitis and patients with rheumatoid arthritis taking non-steroidal anti-inflammatory drugs (NSAID). The increased intestinal permeability in ankylosing spondylitis is independent of disease activity. These findings suggest that the increased permeability is caused by NSAID treatment and is probably not a primary lesion of small bowel mucosa.

Adult↗
PubMed1991

Diagnosis of the abuse of magnesium and stimulant laxatives.

A reliable diagnosis of laxative abuse can only be reached by chemical analysis. We report a modified thin layer chromatography approach for the detection and confirmation of over-the-counter colonic stimulant laxatives. Potential interference by dietary and drug components chemically similar to anthraquinones was investigated and the method was found to be specific in this respect. The diagnosis of magnesium laxative abuse is more difficult since magnesium is a component of body fluids. By inducing diarrhoea with magnesium salts in volunteers we have established that the diagnosis can be made by measuring magnesium concentrations in stool water, with 30 mmol/L being an appropriate cut-off concentration.

Cathartics↗
PubMed1991

Measurement of bone collagen degradation in hyperthyroidism and during thyroxine replacement therapy using pyridinium cross-links as specific urinary markers.

UNLABELLED: Urinary excretion of the bone collagen derived pyridinium cross-links pyridinoline (PYD) and deoxypyridinoline (DPD) was measured in 19 patients (4 M:15 F) with untreated thyrotoxicosis, and 20 pre-, and 20 postmenopausal women taking T4 100-200 micrograms daily for autoimmune hypothyroidism. Both PYD and DPD excretion (nanomoles per mmol creatinine) was elevated in the thyrotoxic patients compared to 287 controls; median 131 vs. 26 and 37.5 vs. 7.2, respectively, P less than 0.0001. In premenopausal women mean urinary pyridinium cross-link excretion and serum osteocalcin levels were similar in both T4-treated and matched control groups, despite suppression of serum TSH concentrations to below 0.1 mU/L in 14 of the 20 taking T4. In postmenopausal women mean (+/- 1 SE) urinary PYD excretion (nanomoles per mmol creatinine) was raised in those taking T4, relative to euthyroid controls; 40.0 +/- 2.7 vs. 32.1 +/- 2.3, P less than 0.05. DPD excretion and serum osteocalcin levels were also higher, but not significantly. When only the T4-treated women with a subnormal serum TSH were considered the difference in PYD excretion was more marked, and mean DPD excretion was also significantly elevated; 13.7 +/- 1.3 vs. 10.1 +/- 0.8, P less than 0.05. CONCLUSION: bone collagen breakdown is increased in thyrotoxicosis, and in postmenopausal women taking sufficient T4 to suppress serum TSH. Similarly treated premenopausal women appear to be at lower risk.

Adult↗
PubMed1991

Comparison of different measurements of intestinal permeability in inflammatory bowel disease.

We have compared different measurements of small intestinal permeability in 28 patients with Crohn's disease affecting the small intestine, 14 with ulcerative colitis and 17 controls. Patients and controls were given a drink containing 100 microCi (3.7 MBq) of 51Cr-ethylene diamine tetraacetic acid (51Cr-EDTA), 5 g lactulose, 5 g cellobiose, 1 g rhamnose, and 2 g mannitol. Urine was collected to 6 h after dosing, and then from 6 until 24 h. Recoveries of 51Cr-EDTA, lactulose, rhamnose, and mannitol were expressed as percentages of the amount administered. The only measurement that distinguished patients with Crohn's disease from both controls and patients with ulcerative colitis was the recovery of 51Cr-EDTA in the first 6 h after dosing. The mean recovery in patients with Crohn's disease was 1.07%; in controls, it was 0.35% (p = 0.013); in ulcerative colitis it was 0.39% (p = 0.032 compared to Crohn's; p = 0.492 compared to controls). No other measurement of permeability differentiated the three groups. Recoveries of 51Cr-EDTa and lactulose were highly correlated in each of the three groups. Recovery of rhamnose was significantly correlated with that of mannitol. In the patients with Crohn's disease, recovery of 51Cr-EDTA to 6 h was significantly correlated with some nonspecific laboratory indicators of inflammatory activity, namely, erythrocyte sedimentation rate, platelet count, white blood cell count, serum albumin, and C-reactive protein, but not with hemoglobin.

Adolescent↗
PubMed1990

Polyphosphate production by strains of Acinetobacter.

Of four strains of Acinetobacter isolated from a pilot plant exhibiting enhanced biological phosphate removal from sewage, two strains (RA3116 and RA3117) accumulated more than 10 times the amount of polyphosphate accumulated by the other two strains (RA3114 and RA3123). Variants isolated from RA3116 and RA3117 showed polyphosphate levels similar to RA3114 and RA3123. No correlation was found between the polyphosphate content of the strains and levels of several enzymes that have been implicated in polyphosphate formation.

Acinetobacter↗