Annals of Clinical Biochemistry
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Erythrocyte Membrane Fatty Acid Composition in Hypercholesterolemia The fatty acid composition of the erythrocyte membrane was determined in 22 hypercholesterolaemic patients managed by dietary restriction, and compared with that of 22 normocholesterolaemic controls, roughly matched for age and sex with the patient group. The patients exhibited higher relative proportions of palmitic ( P<0·01) and stearic ( P<0·005) acids and lower relative proportions of linoleic acid ( P<0·05) in the erythrocyte membrane, compared with controls, which could be due to presumed dietary differences between the groups. In the patients, the degree of hypercholesterolaemia was poorly correlated with erythrocyte linoleic acid. Measurement of erythrocyte linoleic acid might prove useful in the routine management of hypercholesterolaemia.
Annals of Clinical Biochemistry - Tập 31 Số 4 - Trang 351-354 - 1994
Biochemical Differences in Human Glomerular Basement Membrane Related to Diabetes and Age Preparations of glomerular basement membrane from diabetic and young and aged normal subjects have been isolated and purified and the component carbohydrates and amino acids quantitatively determined. Diabetic membrane preparations, compared with membranes from young normal subjects, show significant increases in total hexoses, mannose, and galactose and decreases in sialic acid and glucose; the component amino acids show increases in hydroxylysine, proline, and glycine and decreases in lysine, histidine, and leucine. Basement membrane preparations from aged normals show changes in component carbohydrates and amino acids similar to, but not as great as, those seen in the diabetics.
Annals of Clinical Biochemistry - Tập 19 Số 1 - Trang 17-21 - 1982
Salivary Cortisol: A Better Measure of Adrenal Cortical Function than Serum Cortisol Salivary Cortisol concentration was found to be directly proportional to the serum unbound Cortisol concentration both in normal men and women and in women with elevated cortisol-binding globulin (CBG). The correlation was excellent in dynamic tests of adrenal function (dexamethasone suppression, ACTH stimulation), in normals and patients with adrenal insufficiency, in tests of circadian variation and randomly collected samples. Women in the third trimester of normal pregnancy exhibited elevated salivary Cortisol throughout the day. The relationship between salivary and serum total Cortisol concentration was markedly non-linear with a more rapid increase in salivary concentration once the serum CBG was saturated. The rate of equilibrium of Cortisol between blood and saliva was very fast, being much less than 5 minutes. These data, combined with a simple, stress-free, non-invasive collection procedure, lead us to suggest that salivary Cortisol is a more appropriate measure for the clinical assessment of adrenocortical function than is serum Cortisol.
Annals of Clinical Biochemistry - Tập 20 Số 6 - Trang 329-335 - 1983
Concentrations of Organic Acids in the Urine of Healthy Newborn Children Urine concentrations of organic acids were determined by a gas chromatographic technique in healthy, full-term neonates at the ages of 2 and 5 days. Significant reductions in the interindividual variation were obtained by relating the levels of organic acids to urine creatinine concentration or osmolality. Citrate was the predominant organic anion found. Urine concentrations of fumarate, 3-hydroxy-3-methylglutarate, adipate, and suberate decreased during the first week of life, and their concentrations were significantly intercorrelated. It is suggested that these findings reflect the predominantly fat-utilising, hyperketonaemic state during the first days of life. The urine concentrations of the aromatic end-products, p-hydroxyphenylacetate and hippurate, increased during the first week of life, probably as an effect of dietary factors. It is concluded that analysis of intermediary organic acids in urine could be of value in the assessment of the metabolic state in neonates.
Annals of Clinical Biochemistry - Tập 15 Số 1-6 - Trang 245-249 - 1978
Serum calcium, urine calcium and polymorphisms of the calcium sensing receptor gene Background: Recent studies have suggested a correlation between the A986S polymorphism of the calcium sensing receptor (CASR), and serum total and ionized calcium. This study aimed to assess the prevalence of three CASR polymorphisms in a West of Scotland population and relate genotype to serum and urine calcium levels. Methods: Fasting blood and urine samples were obtained from 121 healthy male and female volunteers aged 20-60 years. Volunteers were genotyped for the A986S, Q1011E and R990G polymorphisms using allele-specific amplification and amplification-created restriction site techniques. Total calcium, ionized calcium and urine calcium excretion were measured using automated clinical chemistry analysers. Results: Genotype frequencies for the A986S polymorphism were: AA, 74.4%; AS, 24.8%; SS, 0.8%. There was a small but statistically significant ( P < 0.01) increase in ionized calcium concentration in AS individuals compared with the wild type (1.22 versus 1.20 mmol/L). No statistical difference was detected in serum total calcium or parameters of urine calcium excretion. Genotype frequencies for the remaining polymorphisms were: RR, 82.6%; RG, 16.5%; GG, 0.8% and QQ, 93.4%; QE, 6.6%; EE, 0%. Biochemical parameters in these individuals were not statistically different from the wild type. Conclusion: The increase in serum ionized calcium in the AS group was small and, therefore, unlikely to be of clinical significance.
Annals of Clinical Biochemistry - Tập 43 Số 6 - Trang 503-506 - 2006
Utility of the urine calcium-to-creatinine ratio to diagnose primary hyperparathyroidism in asymptomatic hypercalcaemic patients with vitamin D deficiency Background Primary hyperparathyroidism (PHP) is the most common cause of hypercalcaemia, and often requires surgical treatment. Familial hypocalciuric hypercalcaemia (FHH) has similar biochemical features to PHP, but requires no treatment. The most common biochemical method used to distinguish between PHP and FHH is the urine calcium-to-creatinine ratio (UCCR). Vitamin D deficiency may alter the renal excretion of calcium, but it is unclear how vitamin D deficiency affects the diagnostic performance of UCCR. Aim To examine the reliability of UCCR to detect PHP in patients presenting with asymptomatic hypercalcaemia, in the presence or absence of vitamin D deficiency. Methods One hundred and eighteen UCCR measurements from 97 asymptomatic hypercalcaemic patients diagnosed with PHP presenting to a single specialist endocrine unit were analysed retrospectively. Results A significantly higher proportion of UCCR measurements were <0.010 in patients with serum vitamin D <25 nmol/L when compared with patients with serum vitamin D >25 nmol/L, thus incorrectly suggesting the presence of FHH (proportion of measurements with UCCR >0.010: 11/48 [22.9%], vitamin D <25 nmol/L; 4/70 [5.7%], vitamin D >25 nmol/L; P < 0.001). Urine calcium concentration was 26% lower and serum parathyroid hormone (PTH) was 27% higher in patients with vitamin D deficiency when compared with patients without vitamin D deficiency. Conclusions These data suggest that the presence of vitamin D deficiency is associated with worsened PTH hypersecretion, impairment of urinary calcium excretion and reduced sensitivity of UCCR measurement with respect to the detection of PHP. These data have important clinical implications for the investigation and management of patients with asymptomatic hypercalcaemia.
Annals of Clinical Biochemistry - Tập 48 Số 2 - Trang 126-129 - 2011
Effect of ageing on plasma lipoprotein(a) levels Background Lipoprotein(a) [Lp(a)] is a risk factor for atherosclerosis and increases with age. The purpose of this study was to determine the effect of ageing on Lp(a) for three different apo(a) phenotypes. Methods We measured plasma Lp(a) concentrations in 551 unrelated Japanese subjects (20-88 years of age). We performed statistical analyses separately for three apo(a) phenotypes: the low-molecular-weight (LMW) phenotype with the F, B or S1 isoform, the intermediate-molecular-weight (IMW) phenotype with the S2 isoform and the high-molecular-weight (HMW) phenotype with the S3 or S4 isoform. Results For each phenotype, the mean plasma Lp(a) concentration and the frequency of Lp(a) concentrations ≥ 250 mg/L increased with age. Further, a statistically significant difference was always found between the younger subjects (20-39 years of age) and the elderly (over 60 years). The frequency of coronary heart disease increased with age, particularly for the LMW and IMW phenotypes. Conclusions We conclude that ageing elevates plasma Lp(a) concentrations, which may have a role in the prevalence of coronary heart disease in the elderly, especially those with the LMW or IMW phenotypes.
Annals of Clinical Biochemistry - Tập 39 Số 3 - Trang 237-240 - 2002
Comparison between transcutaneous bilirubinometry and total serum bilirubin measurements in preterm infants <35 weeks gestation Background Neonatal hyperbilirubinaemia is a common treatable cause of brain injury. The treatment for this condition is phototherapy. The decision whether to use phototherapy is currently dependent upon serum bilirubin assay results. However, repeated blood sampling is not only traumatic but may also be a cause of anaemia in neonates. We evaluated a transcutaneous bilirubin assay method to determine whether it was suitable for routine use in preterm infants. Methods One hundred and eighty-three transcutaneous bilirubin measurements were taken contemporaneously with blood samples for laboratory measurement of serum bilirubin. The study was carried out with informed parental consent and approval by the local research ethics committee. Results The transcutaneous bilirubin method (Bili Chek® ) exhibited a consistent positive bias compared with the laboratory bilirubin assay. Consequently, for a given detection rate, the transcutaneous method had a higher screen positive rate, i.e. more neonates would be given phototherapy if transcutaneous bilirubin results were used to decide. There was a margin of safety in the transcutaneous bilirubin assay calibration. Conclusion The BiliChek transcutaneous bilirubin assay is a safe alternative to laboratory bilirubin assay in deciding whether to give preterm neonates phototherapy.
Annals of Clinical Biochemistry - Tập 47 Số 1 - Trang 72-77 - 2010
Stimulating TSH receptor autoantibodies immunoassay: analytical evaluation and clinical performance in Graves’ disease Background Thyroid-stimulating hormone (TSH) receptor (TSHR) autoantibodies (TRAbs) are a heterogeneous group of antibodies (Abs) with different functionalities. Among all TRAbs, only the stimulating ones (S-TRAbs) are considered as the pathogenetic marker of Graves’ disease (GD). To date, the methods available for TRAbs testing are based on immunoassays (IMAs) which detect total serum TRAbs or bioassays which are not suitable in clinical practice, even though they discern Abs functionality. The aim of our work was to evaluate the analytical and clinical performance of a very recent IMA (Immulite TSI method), supposed to test only the serum concentration of S-TRAbs, in comparison with a current method for total TRAbs (Roche/Elecsys IMA). Methods We evaluated serum samples of 145 subjects: 46 with untreated (GD), 36 with chronic autoimmune thyroiditis, 3 with atrophic thyroiditis, 10 with multinodular non-toxic goiter and 50 healthy subjects. Results The method showed an optimal analytical sensitivity and high precision levels (LoB: 0.04 UI/L, LoD:0.07 UI/L, LoQ:0.14 UI/L, intra-assay CV: 4.2–5.9%, inter-assay: 4.5–7.2%). By receiver operating characteristics curve analysis, we obtained a value of 0.57 (sensitivity: 98.0%, specificity: 99.9%) as the best cut-off to distinguish GD, apart from four cases. Passing Bablok regression and Bland Altman analysis pointed out a good correlation and agreement with Roche method (R2 = 0.98, slope = 1.03, bias = −2.70). Conclusions The new method presents very promising analytical characteristics and could be adopted in clinical practice for GD diagnosis. Moreover, the test allows to accurately detect very low values of analyte with a further clinical utility in detecting earlier possible relapses.
Annals of Clinical Biochemistry - Tập 55 Số 1 - Trang 172-177 - 2018
Glycosyl Phosphatidyl Inositol Phospholipase D Activity in Human Serum We measured serum glycosyl phosphatidyl inositol phospholipase D (GPI-PLD) by its alkaline phosphatase releasing activity in healthy and diseased individuals. Linearity with respect to serum concentration was obtained only with very low serum volumes (below about 0·2 μL) necessitating a large predilution of serum to avoid potential artefacts. The assay was sufficiently precise for routine use. Patients with liver disease had lower activities and those with renal disease had higher activities than healthy controls. Following liver transplantation there was no correlation between GPI-PLD and conventional markers of liver function but there was a marked correlation with cholesterol concentration. These observations suggest that liver is a major source of GPI-PLD in serum. Its function remains unknown.
Annals of Clinical Biochemistry - Tập 32 Số 1 - Trang 74-78 - 1995
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