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Biomedical subjects

T R Tickner

Publications and source records attributed to T R Tickner.

At least 19 recordsLinked to original sources
PubMed1991

Use of a non-extraction HPLC technique for measuring angiotensin-converting enzyme under optimum conditions.

A non-extraction high performance liquid chromatography assisted method for the measurement of angiotensin-converting enzyme in serum has been developed. Serum containing the enzyme was incubated with the synthetic substrate, furylacryloylphenylalanylglycylglycine at a concentration approaching 10 times the apparent Km, prior to injection onto a shielded hydrophobic reverse phase high performance liquid chromatography column. This allowed the product to be separated and measured directly without the need for a time consuming protein extraction step. The method is enzymatically sound and avoids the methodological problems associated with automated kinetic assays.

Chlorides↗
PubMed1990

Direct serum injection high-performance liquid chromatographic method for the simultaneous determination of phenobarbital, carbamazepine and phenytoin.

A method is described for the simultaneous measurement of serum levels of three antiepileptic drugs, phenobarbital, phenytoin and carbamazepine, by direct injection high-performance liquid chromatography on a 25-cm Pinkerton internal surface reversed-phase (ISRP) column. Several commonly available compounds were tested and found not to co-chromatograph with the three drugs of interest or the internal standard, 5-(p-methylphenyl)-5-phenylhydantoin. Results obtained on patients' samples with this method compared well with those from enzyme-multiplied immunoassay technique (EMIT).

Carbamazepine↗
PubMed1989

Non-extraction HPLC method for the simultaneous measurement of theophylline and caffeine in human serum.

A non extraction HPLC method is described for the simultaneous measurement of theophylline and caffeine in human serum using a Pinkerton ISRP column and u.v. detection at 275 nm. The method is suitable for therapeutic monitoring of theophylline levels in adults and, in particular, quantitation of both theophylline and caffeine in premature neonates where as little as 10 microL of sample can be used. Comparison of theophylline levels obtained by this method with EMIT analysis show a correlation coefficient of 0.97 (n = 37) in adults and 0.79 (n = 16) in premature neonates. There was no correlation between serum theophylline and caffeine levels in premature neonates receiving theophylline therapy. No interference was encountered from endogenous plasma components or other drugs in the 53 patients studied. Precision of the assays compares well with reported values for extraction HPLC and immunochemical analyses.

Caffeine↗
PubMed1989

Investigation of a persistently raised serum AST.

The AST responsible for a raised enzyme activity, with otherwise normal biochemistry, in a single individual over a 16-month period has been characterized as an IgG (lambda)-AST complex by (i) estimation of the molecular size by gel exclusion chromatography on Sephadex G200, (ii) agarose gel electrophoresis, (iii) immunoprecipitation by anti-immunoglobulin antisera and (iv) adsorption on to protein A-agarose.

Adsorption↗
PubMed1988

A non-extraction HPLC method for the simultaneous determination of serum paracetamol and salicylate.

A direct injection HPLC method for the sumultaneous measurement of serum paracetamol and salicylate is described using a Pinkerton internal surface reversed-phase column with benzoic acid as internal standard. The method is linear to at least 1000 mg/L for both drugs and shows good precision at levels of 62-500 mg/L. None of the drugs tested for interference affected the quantitation of either drug. In patient samples, the values obtained with this method correlated well with those from enzymatic paracetamol and Trinder salicylate methods.

Acetaminophen↗
PubMed1980

The mechanism of hyperlipidaemia in nephrotic syndrome--role of low albumin and the LCAT reaction.

Diminished autologous LCAT activity was found in patients with proteinuria. This was due to substrate limitation and albumin appeared the most likely limiting factors. It is suggested that low albumin can contribute to the hyperlipidaemia of nephrotic syndrome through its role on the LCAT reaction. Evidence of the ability of triglyceride to enhance homologous LCAT activity was also noted.

Adolescent↗
PubMed1979

An evaluation of a simple polyacrylamide gel electrophoresis system for lipoproteins and its use for the characterisation of hyperlipoproteinaemia.

The use of polyacrylamide gel electrophoresis as a screening procedure for the characterisation of hyperlipoproteinaemia is described. Sixty-one samples were investigated and classified by four different methods: (1) chemical profile derived from visual appearance and estimation of total cholesterol and triglyceride; (2) 'SML' profile by nephelometry; (3) electrophoresis on agarose gel; and (4) electrophoresis on polyacrylamide gel. Polyacrylamide gel electrophoresis showed the closest correlation with the chemical profile when compared with the other two methods. Polyacrylamide gel electrophoresis was found to be a rapid, reliable, and satisfactory procedure for plasma lipoprotein phenotyping.

Blood Protein Electrophoresis↗
PubMed1978

A simple colorimetric method for the estimation of plasma biliverdin.

A new colorimetric method for the assay of biliverdin in biological fluids is described. The method, based upon the reaction of biliverdin with barbituric acid, offers improved sensitivity and selectivity when compared to direct spectrophotometric measurements. Using this method biliverdinaemia was observed in two patients with obstructive jaundice of malignant origin.

Ascorbic Acid↗
PubMed1978

The characterisation of thiobarbituric acid reactivity in human plasma and urine.

The specificity of the thiobarbituric acid reaction (TBA) has been investigated using techniques of high-performance thin-layer chromatography and spectrofluorimetry. It was found that malondialdehyde (MDA) derived from different lipid and nonlipid origins formed the same MDA-TBA complex. This complex could be separated from other TBA-reactive compounds by both chromatography and spectrofluorimetry. Normal human plasma and urine both formed an MDA-TBA complex along with other TBA-reactive compounds. In plasma this was associated mainly with phosphatidylcholine and appeared to be peroxidic in reaction. Urine, however, contained polar MDA-forming compounds probably resulting from the oxidation of 2-deoxyaldoses during the acid-heating stage of the TBA test.

Chromatography, Thin Layer↗
PubMed1978

The integrative role of lecithin:cholesterol acyl transferase in triglyceride clearance.

There is evidence that not only lipoprotein lipase (LPL) but also lecithin:cholesterol acyl transferase (LCAT) are involved in the directional flow of triglyceride (TG) from endogenous very low density lipoproteins (VLDL) and chylomicrons as part of a general energy storage pathway. Evidence is given to suggest that LCAT plays an integrative role in this process.

Animals↗
PubMed1977

Plasma lipoprotein patterns in patients receiving dialysis therapy for chronic renal failure.

A study is reported of the prevalence, nature and possible aetiology of the hyperlipidaemia found in a group of 74 patients receiving maintenance dialysis. Sixty patients were receiving haemodialysis and 14 peritoneal dialysis. Sixty-four per cent of the male and 83% of the female patients had a lipoprotein abnormality which was predominantly of the Type IV pattern, probably due to a combination of increased hepatic triglyceride synthesis and diminished peripheral clearance.

Adolescent↗