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Biomedical subjects

A M van Rij

Publications and source records attributed to A M van Rij.

18 recordsLinked to original sources
PubMed1991

Developing a system for surgical audit.

A system for surgical audit, which has been developed during a 6 year period in an active surgical unit of a teaching hospital, is described. Following a review of the first 3 years of our computerized audit, major modifications to the audit processes and computer program were made. The key lessons for systematic practical surgical audit include the collection of essential data only, establishing audit processes within current department practices, verification of data by consultants, and the provision of incentives for all users. The current system is proving a valuable resource for quality assurance, surgical training and departmental management.

Computer Systems↗
PubMed1990

Coding for surgical audit.

A simple system of codes for operations, diagnoses and complications, developed specifically for computerized surgical audit, is described. This arose following a review of our established surgical audit in which problems in the retrieval of data from the database were identified. Evaluation of current methods of classification of surgical data highlighted the need for a dedicated coding system that was suitable for classifying surgical audit data, enabling rapid retrieval from large databases. After 2 years of use, the coding system has been found to fulfil the criteria of being sufficiently flexible and specific for computerized surgical audit, yet simple enough for medical staff to use.

Diagnosis-Related Groups↗
PubMed1988

Percutaneous transluminal angioplasty for the ischaemic lower limb: the early Dunedin experience.

A consecutive series of 60 percutaneous transluminal angioplasties has been performed in 53 patients with severe peripheral ischaemia over a 4 year period. There were 78 lesions dilated with an initial technical success rate of 78%. Forty-eight lesions were dilated for severe claudication and 30 for rest pain or necrosis. There was a mean followup of 24 months (range 9-56) for the immediately successful angioplasties. When these were analysed according to symptomatic relief, 59% of claudicants with iliac lesions were still improved at 2 years, compared with 86% of those with femoropopliteal lesions. Amongst patients treated for rest pain or necrosis there was a 100% success rate at 2 years for iliac lesions, compared with 49% for femoropopliteal lesions. The overall success of this procedure in this high risk group is reflected by the fact that at 2 years 85% of claudicants and 72% of those with rest pain and necrosis have avoided any further procedure. This encouraging early experience confirms the place of interventional radiology in the management of peripheral vascular disease.

Adult↗
PubMed1988

Plasma thiobarbituric acid reactivity: reaction conditions and the role of iron, antioxidants and lipid peroxy radicals on the quantitation of plasma lipid peroxides.

The effects of Fe3+, lipid peroxy radicals and the antioxidant butylated hydroxytoluene on the 2-thiobarbituric (TBA) acid quantitation of plasma lipid peroxides were investigated. Whole plasma and plasma fractions prepared by trichloroacetic acid (TCA) protein precipitation and lipid extraction, demonstrated markedly differing TBA reactivities in the presence or absence of added Fe3+. Examination of the spectral profiles of the TBA reacted whole plasma and TCA precipitated fractions demonstrated the presence of interfering compounds which gave rise to an artifactual increase in lipid peroxide concentrations. In contrast the TBA reacted lipid extracts had low levels of interfering compounds that could be removed by our previously described high pressure liquid chromatographic method (Wade, Jackson and van Rij (1985) Biochem. Med. 33, 291-296). Further characterization of the TBA reactivity of the lipid extract showed that Fe3+ at an optimal concentration of 0.5 mM was necessary for the quantitative decomposition of the lipid peroxides to the TBA reactive product malondialdehyde (MDA). However the presence of Fe3+ resulted in further peroxidation of any unsaturated lipids present. Butylated hydroxytoluene (BHT) at an optimal concentration of 1.4 mM inhibited Fe3+ stimulated peroxidation without affecting the formation of the MDA-TBA chromogen. Using a standardized TBA test with plasma lipid extracts and the addition of optimal concentrations of Fe3+ and BHT, we have determined the mean concentration of lipid peroxides in 30 healthy human subjects to be 102.7 +/- 20.0 ngm/ml.

Butylated Hydroxytoluene↗
PubMed1988

Selenium and vitamin E supplementation: activities of glutathione peroxidase in human tissues.

Twenty-seven New Zealand women received daily for 4 wk, 200 micrograms selenium as sodium selenite, 170 mg alpha-tocopherol acetate, or a placebo. Se supplementation raised platelet selenoglutathione peroxidase (Se-GSHPx, p less than 0.001) and also Se and Se-GSHPx in whole blood and plasma. Se concentrations and Se-GSHPx activities in liver biopsies taken after supplementation were greater (p less than 0.05) for the Se group and a good correlation was found between Se and Se-GSHPx in liver and muscle for all subjects. Platelet Se-GSHPx correlated well with Se and Se-GSHPx in liver, indicating its suitability for assessing Se bioavailability. This is the first reported study of relationships between Se and Se-GSHPx in human liver and muscle tissue and platelet Se-GSHPx after Se supplementation. These observations verify in man relationships observe in animal studies, giving support to assumptions made in methods for assessing Se status and bioavailability in man, in particular the use of platelet GSHPx.

Adaptation, Physiological↗
PubMed1988

The absence of adaptive changes in tissue activities of glutathione-S-transferase, superoxide dismutase and catalase following selenium and vitamin E supplementation in subjects with low selenium status.

Three groups of New Zealand women were given daily in a double blind randomised study, 200 micrograms Se as sodium selenite, 170 mg alpha-tocopherol or a placebo for 4 wk. Activities of glutathione-S-transferase, superoxide dismutase and catalase were assayed in erythrocytes, plasma and platelets and in liver and muscle biopsy tissues. No changes in activities of any of these tissue enzymes were observed in any of the three groups. There were also no changes in non-selenium dependent glutathione peroxidase activities in liver or plasma. The lack of changes in any of these enzymes following selenium supplementation suggests that adaptive changes to the low selenium status of these subjects had not occurred through these lipid peroxidation defense mechanisms.

Adult↗
PubMed1987

Lipid peroxidation and malondialdehyde in the synovial fluid and plasma of patients with rheumatoid arthritis.

The concentration of lipid peroxides in the plasma and synovial fluid of 65 arthritic patients was determined using a new ion-pairing reverse phase HPLC technique. Patients with rheumatoid arthritis receiving only non-steroidal anti-inflammatory drugs, had a significantly higher mean concentration of lipid peroxides in synovial fluid samples (162 +/- 22.0 micrograms/l) than osteoarthritic patients (40.0 +/- 8.0 micrograms/l, p less than 0.0001). Mean concentrations in both groups correlated strongly with the level of beta-glucuronidase activity as a measure of lysosomal enzyme release (r = 0.71, p less than 0.0001). Contrary to previous reports by investigators using less specific methods, we were unable to demonstrate any increase in plasma levels of lipid peroxides in the rheumatoid patient. Treatment of rheumatoid arthritis with D-penicillamine was associated with a significant reduction of lipid peroxide levels (83.2 +/- 11.5 micrograms/ml, p less than 0.002), suggesting that this drug may function as an oxygen radical scavenger in the joint cavity. These results give further support to the concept of oxygen-free radicals playing an important role in the pathogenesis of chronic inflammatory disorders.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1987

Altered platelet lipoxygenase activity in patients with low selenium.

1. Arachidonic acid metabolism through the lipoxygenase pathway in platelets was investigated in 11 patients with low selenium (Se) nutritional status and compared with 14 patients with a normal Se status. 2. Plasma and whole blood Se levels, as well as plasma, whole blood and platelet glutathione peroxidase (GSHPx) activity, were measured in both groups and found to be significantly lower in the group with low Se status. 3. Studies on [14C]arachidonic acid stimulated platelets demonstrated that reduced conversion of the active metabolite 12-hydroperoxyeicosatetraenoic acid to 12-hydroxyeicosatetraenoic acid occurred in patients with low Se nutrition. 4. Changes in [14C]arachidonic acid metabolism are attributed to reduced activity of the seleno-enzyme GSHPx. The effects of other factors cannot be entirely excluded.

Arachidonic Acid↗
PubMed1987

Parenteral nutrition and tumour growth in the patient with complicated abdominal cancer.

Parenteral nutrition has been advocated as an important adjunct in the treatment of the patient with cancer undergoing surgery, chemotherapy and radiotherapy. However there is universal agreement that parenteral nutrition does not have a stimulatory effect on tumour growth. Four cases are reported, in complicated abdominal cancer involving only surgery, in which a claim that acceleration of tumour growth by parenteral nutrition can be made.

Abdominal Neoplasms↗
PubMed1987

The metabolism of low molecular weight hydrocarbon gases in man.

The metabolism of ethane and pentane in man is demonstrated to occur from the uptake of an enriched atmosphere of these gases in a rebreathe spirometer circuit. Dithiocarb, an inhibitor of alkane metabolism, reduced uptake and increased the respiratory excretion of these gases. This effect was least marked for the slowly metabolised ethane. Therefore the endogenous production of ethane as measured by respiratory excretion is less affected. However pentane is rapidly metabolised and this limits the use of simple respiratory excretion of pentane as a measure of in vivo lipid peroxidation.

Disulfiram↗
PubMed1985

In vivo lipid peroxidation in man as measured by the respiratory excretion of ethane, pentane, and other low-molecular-weight hydrocarbons.

A method for the collection and measurement of low-molecular-weight volatile hydrocarbons exhaled in human breath as a result of lipid peroxidation in vivo is described. Subjects breathed in a closed-circuit rebreathe system and samples were taken over a 2-h period, extracted, and analyzed by gas-liquid chromatography isothermally on a 3-m column of n-octane/Porasil-C. Immediately, prior to rebreathing subjects were equilibrated with scrubbed air containing very low ambient levels of hydrocarbons to eliminate the effects of previous exposure to hydrocarbon-contaminated environments. Only under these conditions could hydrocarbon exhalation be measured. In the rebreathe system C3-C5 hydrocarbon concentrations increased linearly initially but reached a steady state after 1.5 h while ethane did not approach equilibrium even after 2 h. The steady-state equilibrium was demonstrated to be due to tissue uptake and metabolism of the hydrocarbon gases. Ethane metabolism was slow, allowing calculation of the endogenous production from the initial rate of change in concentration and an experimentally determined total body solubility coefficient. Similar calculations for pentane were not valid as metabolism was rapid; therefore production was estimated from the equilibrium value reached after 2 h. Ethane production in six healthy subjects was calculated to be 95.1 +/- 19.0 pmol/kg/h while equilibrium values for pentane were 120 +/- 50 pmol/liter. This method now allows the quantitation in man of lipid peroxidation in vivo.

Breath Tests↗
PubMed1979

Blood selenium and glutathione peroxidase activity in normal subjects and in surgical patients with and without cancer in New Zealand.

This study was carried out in Otago, South Island, where most arable land has a low soil selenium content (less than 0.5 microgram/g) and where selenium (Se) responsive diseases in livestock are common. Se concentration in whole blood, erythrocytes and plasma, and activity of glutathione peroxidase (EC 1.11.1.9) were measured in blood from 104 healthy Otago residents, 80 patients with cancer and 66 noncancer surgical patients. The older residents over 60 years had lower blood Se levels (0.047 +/- 0.010 microgram Se/ml blood) than the young and middle-aged (0.060 +/- 0.012 microgram Se/ml). Blood Se levels of cancer patients were no lower than those of elderly subjects and patients without cancer, and were less than half comparable United States values. Blood Se levels were decreasing in two cancer patients, and the lowest values (less than 0.03 microgram Se/ml blood) were obtained for five cancer patients, and two noncancer patients after a long period of inanition; these were similar to values for patients on parenteral nutrition with negligible intakes. Lower blood Se levels were associated with lower serum albumin and enzyme activities. It is suggested that low Se status of cancer patients was more likely a consequence of their illness than the cause of the cancer.

Adult↗
PubMedDate not supplied

Selenium and total parenteral nutrition.

Despite the increasing recognition of selenium (Se) as an essential trace element in man, little is known about its metabolism during total parenteral nutrition (TPN) and the possible development of Se deficiency in high risk patients. From a general population known by its geographical location to have low Se blood levels, we studied a group of 23 surgical patients receiving TPN for at least one week. Whole blood Se levels were less than in the normal general population and, being some of the lowest observed in adult man, approached levels observed in animals with Se-responsive syndromes. Se continued to be lost predominantly in the urine although the Se content of the TPN fluids was very low (less than 0.6 micrograms/24 hr). Patients with excessive volumes of gastrointestinal excretion lost more Se. Se supplementation may be required in some patients receiving TPN.

Humans↗