Keith R. Allen

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BACKGROUND Aluminium toxicity as a cause of dementia, osteodystrophy and anaemia in patients receiving renal dialysis was first described in the 1970s and led to the regular monitoring of aluminium in plasma and dialysate water. However, aluminium phosphate binders have now been replaced by calcium-based binders or sevelamer and reverse osmosis (RO) water(More)
Buprenorphine is an opioid analgesic drug that is used as an alternative to methadone to treat heroin addiction. Established methods for the analysis of buprenorphine and its metabolites in urine such as gas chromatography-mass spectrometry (GC-MS) involve complicated sample extraction procedures. The aim of the present study was to develop a sensitive yet(More)
BACKGROUND Carcinoid disease is an uncommon disorder resulting from tumours of the enterochromaffin cells. Current biochemical investigation usually involves the measurement of 5-hydroxyindole-3-acetic acid (5-HIAA) in 24-h urine collections. Because of the problems associated with urine collections (i.e. inconvenience, accuracy of collection and(More)
BACKGROUND There is increasing interest in the use of oral fluid as the matrix for the detection of drugs of abuse which requires the use of sensitive immunoassays to achieve the low detection limits required. The use of liquid chromatography linked to tandem mass spectrometry (LC/MS/MS) is explored as a possible replacement for immunoassay in screening for(More)
In patients with carcinoid disease, urinary concentration of the serotonin metabolite 5-hydroxyindole acetic acid (5-HIAA) is currently used to monitor disease progression or response to treatment as it is the metabolic end-product resulting from free and stored serotonin turnover. However, due to the undignified, cumbersome and error-prone nature of 24-h(More)
Confirmation of the presence of illicit drugs in human fluids by liquid chromatography linked to atmospheric pressure ionisation tandem mass spectrometry (LC/MS/MS) is becoming increasingly popular. A rapid LC/MS/MS method is described using reversed phase gradient elution chromatography on a 50 x 3 mm base deactivated C8 column with identification of drugs(More)
Stimulating the body's natural healing at the cellular level can be achieved through the application of growth factors located within platelets. Once combined with a mixture of calcium and thrombin, this substance, now referred to as autologous platelet gel (APG), can be applied to surgical wound sites for patients undergoing cardiac surgery. The purpose of(More)
Urine is recognized as the prime matrix for drug test screening with well-established methods and testing protocols. Its major limitation is with regard to the inconvenience of sample collection and lack of integrity due to adulteration, dilution, drug spiking or sample exchange. The question is whether oral fluid, with its apparent better sample integrity,(More)
BACKGROUND Micronutrient deficiencies may occur in patients with malignancy due to a variety of possible causes, including unbalanced dietary intake and adverse effects of treatment. In addition, many patients show signs of a chronic inflammatory response, which can affect circulating concentrations of certain vitamins and trace elements. Our aim was to(More)