bluuebunny/crossref_metadata_2025 huggingface dataset:
Immunomodulatory drug CC-5013 overcomes drug resistance and is well tolerated in patients with relapsed multiple myeloma
Authors: Richardson Paul G. , Schlossman Robert L. , Weller Edie , Hideshima Teru , Mitsiades Constantine , Davies Faith , LeBlanc Richard , Catley Laurence P. , Doss Deborah , Kelly Kathleen , McKenney Mary , Mechlowicz Julie , Freeman Andrea , Deocampo Reggie , Rich Rebecca , Ryoo Joan J. , Chauhan Dharminder , Balinski Kathe , Zeldis Jerome , Anderson Kenneth C.
Published: October 2002

Thalidomide (Thal) can overcome drug resistance in multiple myeloma (MM) but is associated with somnolence, constipation, and neuropathy. In previous in vitro studies, we have shown that the potent immunomodulatory derivative of thalidomide (IMiD) CC-5013 induces apoptosis or growth arrest even in resistant MM cell lines and patient cells, decreases binding of MM cells to bone marrow stromal cells (BMSCs), inhibits the production in the BM milieu of cytokines (interleukin-6 [IL-6], vascular endothelial growth factor [VEGF], tumor necrosis factor-α [TNF-α]) mediating growth and survival of MM cells, blocks angiogenesis, and stimulates host anti-MM natural killer (NK) cell immunity. Moreover, CC-5013 also inhibits tumor growth, decreases angiogenesis, and prolongs host survival in a human plasmacytoma mouse model. In the present study, we carried out a phase 1 CC-5013 dose-escalation (5 mg/d, 10 mg/d, 25 mg/d, and 50 mg/d) study in 27 patients (median age 57 years; range, 40-71 years) with relapsed and refractory relapsed MM. They received a median of 3 prior regimens (range, 2-6 regimens), including autologous stem cell transplantation and Thal in 15 and 16 patients, respectively. In 24 evaluable patients, no dose-limiting toxicity (DLT) was observed in patients treated at any dose level within the first 28 days; however, grade 3 myelosuppression developed after day 28 in all 13 patients treated with 50 mg/d CC-5013. In 12 patients, dose reduction to 25 mg/d was well tolerated and therefore considered the maximal tolerated dose (MTD). Importantly, no significant somnolence, constipation, or neuropathy has been seen in any cohort. Best responses of at least 25% reduction in paraprotein occurred in 17 (71%) of 24 patients (90% confidence interval [CI], 52%-85%), including 11 (46%) patients who had received prior Thal. Stable disease (less than 25% reduction in paraprotein) was observed in an additional 2 (8%) patients. Therefore, 17 (71%) of 24 patients (90% CI, 52%-85%) demonstrated benefit from treatment. Our study therefore provides the basis for the evaluation of CC-5013, either alone or in combination, to treat patients with MM at earlier stages of disease.
Expression of rat complement control protein Crry on tumor cells inhibits rat natural killer cell–mediated cytotoxicity
Authors: Caragine Theresa A. , Imai Masaki , Frey Alan B. , Tomlinson Stephen
Published: October 2002

Crry is a rodent membrane–bound inhibitor of complement activation and is a structural and functional analog of the human complement inhibitors decay-accelerating factor and membrane cofactor protein. We found previously that expression of rat Crry on a human tumor cell line enhances tumorigenicity in nude rats. In this study, we investigated the effect that rat Crry expressed on tumor cells has on rat cell–mediated cytotoxicity and antibody-dependent cell-mediated cytotoxicity (ADCC). The expression of rat Crry on the surface of different human tumor cell lines inhibited ADCC mediated by rat natural killer (NK) cells. C3 opsonization is known to enhance NK cell–mediated cytolysis, and a potential mechanism for Crry-mediated inhibition of NK cell lysis is through Crry modulation of C3 deposition on target cells. However, the transfection of tumor cell lines with Crry enhanced their resistance to NK cell–mediated lysis in the absence of exogenous complement. The resistance of Crry-expressing tumor cells to NK cell–mediated ADCC could be reversed by treatment with anti–Crry F(ab)2. In addition, anti–Crry F(ab)2 enhanced the susceptibility of 13762 rat mammary adenocarcinoma cells (that endogenously express Crry) to ADCC mediated by allogeneic rat NK cells in the absence of added complement. We found no evidence that rat NK cells were a source of complement for target cell deposition during the in vitro cytolysis assay. These data suggest a novel function for rat Crry in tumor immune surveillance that may be unrelated to complement inhibition.
Cytosolic pH and the inflammatory microenvironment modulate cell death in human neutrophils after phagocytosis
Authors: Coakley Raymond J. , Taggart Clifford , McElvaney Noel G. , O'Neill Shane J.
Published: October 2002

Following phagocytosis in vivo, acidification of extracellular pH (pHo) and intracellular metabolic acid generation contribute to cytosolic proton loading in neutrophils. Cytosolic pH (pHi) affects neutrophil function, although its regulation is incompletely understood. Its effect on mechanisms of neutrophil death is also uncertain. Thus, we investigated pHi regulation in Escherichia coli–exposed neutrophils, at various pathogen-to-phagocyte ratios (0:1-50:1), under conditions simulating the inflammatory milieu in vivo and correlated pHi changes with mechanisms of neutrophil death. Following phagocytosis, proton extrusion was dominated early by passive proton conductance channels, and later by Na+/H+ exchange (NHE). H+-translocating adenosine triphosphatase (V-ATPase) pHi regulation was evident primarily at lower bacterial densities. At physiologic pHo, lower pathogen-to-phagocyte ratios alkalinized pHi and inhibited apoptosis, whereas higher ratios acidified pHi (despite proton extrusive mechanisms) and promoted apoptosis. Necrosis was induced by high-density bacterial exposure at reduced pHo. Following phagocytosis, targeted inhibition of NHEs, proton conductance channels, or V-ATPases (amiloride, ZnCl2, or bafilomycin, respectively) moderately hyperacidified pHi and accelerated apoptosis. However, in combination they profoundly acidified pHi and induced necrosis. Proinflammatory mediators in vivo might affect both pHi regulation and cell death, so we tested the effects of bronchoalveolar lavage (BAL) fluid from patients with cystic fibrosis (CF) and healthy subjects. Only CF BAL fluid alkalinized pHi and suppressed apoptosis at physiologic pHo, but failed to prevent necrosis following phagocytosis at low pHo. Thus, a precarious balance between cytosolic proton loading and extrusion after phagocytosis dictates the mode of neutrophil cell death. pHi/pHo might be therapeutically targeted to limit neutrophil necrosis and protect host tissues during necrotizing infections.
Chronic lymphocytic leukemia preceded by cold agglutinin disease: intraclonal immunoglobulin light-chain diversity inVH4-34 expressing single leukemic B cells
Authors: Ruzickova Sarka , Pruss Axel , Odendahl Marcus , Wolbart Karsten , Burmester Gerd-Rüdiger , Scholze Jürgen , Dörner Thomas , Hansen Arne
Published: October 2002

Autoimmune phenomena may precede or accompany lymphoid malignancies, especially B-chronic lymphocytic leukemia (B-CLL). We report a patient with a 7-year history of primary (idiopathic) cold agglutinin (CA) disease in whom B-CLL subsequently developed. Immunophenotyping and single-cell reverse transcription–polymerase chain reaction (RT-PCR) were applied to investigate the origin and diversification of leukemic B cells. The obtained data indicate a memory cell-type origin of the B-CLL cells. Remarkably, theIgVκ genes of the B-CLL cells showed intraclonal diversity, whereas the mutational pattern of their paired IgVH genes were invariant. Thus, the light-chain–restricted intraclonal diversity in individual leukemic B cells in this patient strongly indicates a differential regulation or selection of the ongoing mutational process. Of note, our findings suggest that this B-CLL had developed from the patient's CA-producing B-cell population.
Electrochemical Reduction and Differential Pulse Polarographic Determination of Butralin and Isopropalin in Environmental Samples at a Mercury Electrode
Authors: Sreedhar Mallipattu , Reddy Srinivasulu Jayarama
Published: October 2002

The electrochemical reduction behavior of two dinitroaniline herbicides, Butralin (BN) and Isopropalin (IN), at a mercury electrode is described based on different voltammetric techniques in various buffer solutions at different pH values. The nature of the electrode process has been examined. A reduction mechanism was proposed. Britton–Robinson (BR) buffer of pH 4.0 was found to be best media for the analysis of the compounds. Both standard addition and calibration methods were used for analysis. The detection limits were found to be 6 × 10−8 M (M = mol dm−3) for BN and for 1.5 × 10−8 M for IN. A differential pulse polarographic method was developed for the determination of the herbicides in grains and soils as well as water samples.
Accumulated lipids, aberrant fatty acid composition and defective cholesterol ester hydrolase activity in cholesterol ester storage disease
Authors: Todoroki Toru , Matsumoto Kojiro , Watanabe Kiyoaki , Tashiro Yukio , Shimizu Makoto , Okuyama Torayuki , Imai Kazuhiro
Published: October 2002

We confirmed accumulation of glycogen and lipids, particularly cholesterol esters, in the liver of a patient with cholesterol ester storage disease (CESD). Hepatic cholesterol ester concentration was 100-200 times that found in normal livers. Analysis of the fatty acid composition indicated a higher proportion (41%) of cholesterol linoleate (C18-2), a slightly lower proportion (33%) of cholesterol oleate (C18-1) and normal proportions (14%) of cholesterol palmitate (C16-0) in the CESD patient compared with the control. This fatty acid composition of cholesterol esters and the fatty acid composition of other classes of lipids in the patient's liver resembled that of LDL. We also found that acid cholesterol ester hydrolase activity in the CESD liver was reduced to 5% of that in the control liver, while neutral cholesterol ester hydrolase activity remained at the control level. These results suggest that accumulated cholesterol esters were derived mainly from serum LDL and that the accumulation resulted from lack of acid cholesterol ester hydrolase.
A model for harmonization of routine clinical chemistry results between clinical laboratories
Authors: Baadenhuijsen Henk , Scholten Ruud , Willems Hans L , Weykamp Cas W , Jansen Rob T P
Published: October 2002

Clinical chemistry laboratory results from different laboratories often show large between-laboratory variation due to factors such as differences in method principles, method applications, calibration procedures or the application of different instrument factor settings within the same calibration procedure. We have examined the possible use of common calibrators to reduce this variation. Three different calibrators were compared: A, freeze-dried preparations of pooled patients' serum samples, spiked to give three concentration levels; B, freeze-dried preparations of pooled patients' serum samples selected on the basis of elevated enzyme activities at three levels; C, a single calibrator consisting of frozen pooled serum samples. These calibrators were sent to 11 participating laboratories together with 14 fresh patients' serum samples. We report the variation of the results of 21 general clinical chemistry analytes obtained in the patients' serum samples before and after recalculation on the basis of the results of the calibrators. For most analytes the use of a multiple point linear regression calibration function is able to reduce the between-laboratory variation considerably from more than 30% (enzymes) to values well within the bias limits set by European quality specifications, when the necessary conditions are met. These conditions include the commutability of the calibrator(s) with fresh patients' material. For the enzymes, calibrator material originating from selectively pooled patients' samples appeared to be necessary, whereas for the substrates selectively pooled serum calibrators spiked with exogenous supplements may be used. For harmonization to be effective in practice, calibrators need to be stable over time and to carry assigned values set by certified reference laboratories, and the quality performance of participating laboratories should be appropriately monitored.
Application and validation of a urinary methadone metabolite (EDDP) immunoassay to monitor methadone compliance
Authors: George S , Parmar S , Meadway C , Braithwaite R A
Published: October 2002

A total of 1381 urine specimens were screened using a Microgenics CEDIA urinary primary methadone metabolite (2-ethylidene-1,5-dimethyl-3,3- diphenylpyrrolidine; EDDP) immunoassay (cut-off calibrator concentration of 100 µg/L) in combination with a Dade Behring EMIT urinary methadone immunoassay (cut-off calibrator concentration of 300 µg/L). Of these, 642 (46%) were found to be positive using the EDDP assay but only 541 (39%) were found to be positive by the methadone assay.

Out of the 108 specimens which were EDDP-positive but negative by the methadone assay, 47 (7%) could not be confirmed as positive using the routine in-house method of gas chromatography incorporating nitrogen-specific detection. Of these 47 results, 38 were re-screened using a more sensitive gas chromatography-mass spectrometry (GC-MS) technique, which demonstrated the presence of EDDP in every case. There was insufficient specimen to analyse the remaining nine samples. There were seven specimens which gave negative results by the EDDP and GC-MS assays but which had methadone concentrations ranging from 4000 to 37 500 µg/L. These were therefore presumed to be 'spiked' with methadone, i.e. to have had methadone added to the specimen to yield positive screening results and simulate compliance. It is concluded that the Microgenics CEDIA EDDP assay is a sensitive and reliable technique to determine the compliance of subjects prescribed methadone for opiate detoxification and maintenance.
Analysis of urine for drugs of abuse using mixed-mode solid-phase extraction and gas chromatography-mass spectrometry
Authors: Paterson Susan , Cordero Rosa , McCulloch Scott , Houldsworth Philip
Published: October 2002

A method for the simultaneous analysis of urine for the major drugs of abuse is described. The analytical procedure uses solid-phase extraction (SPE), gas chromatography-mass spectrometry (GC-MS) and a semi-automated identification process. It allows simultaneous extraction, derivatization and analysis of acidic, neutral and basic drugs from urine. Urine samples were subjected to enzymatic hydrolysis followed by SPE using Bakerbond narc-2 columns. The eluant was selectively derivatized with N-methyl-bis-trifluoroacetamide (MBTFA) and N-methyl- N-trimethylsilyltrifluoroacetamide + 1% trimethylchlorosilane. Analysis was performed using a GC-MS system operating in full scan mode. A simple macro programme was written to enhance the mass spectra identification capabilities of the MS software by producing extracted ion chromatograms (EIC) for the drugs of interest. Once a suspect compound was indicated by EIC, the mass spectrum of the compound was searched manually against reference libraries for positive identification and the retention time checked against that of the standard. This procedure has increased both the amount and the reliability of information given to clinicians without increasing the cost per sample. The system has been in routine operation for 24 months, processing up to 40 urine samples per day, with a usual turn-around time of 48 h.
α-fetoprotein variants in a case of pancreatoblastoma
Authors: Chan M H M , Shing M M K , Poon T C W , Johnson P J , Lam C W K
Published: October 2002

We describe a 6-year-old boy with histologically confirmed pancreatoblastoma and a markedly elevated serum α-fetoprotein (AFP) concentration. Due to local tumour invasion, cytotoxic chemotherapy was given to debulk the tumour before attempting surgical resection. Serial serum AFP concentrations were measured on this patient. During chemotherapy there was a > 95% fall in total AFP. Tumour-specific variants of AFP, detected by isoelectric focusing, also disappeared during chemotherapy but recurred when chemotherapy was withdrawn. It is suggested that although there was no change in overall size of the tumour, as assessed by various imaging techniques, the changes in serological markers may indicate that the treatment did in fact cause considerable tumour necrosis. AFP and its variants may be useful markers of tumour response in patients with pancreatoblastoma. The expression of AFP and its variants in pancreatoblastoma may be related to the embryonic origin of the pancreas.
Provision of interpretative comments on biochemical report forms
Authors: Marshall William J , Challand Gordon S
Published: October 2002

Providing interpretative comments on reports, particularly those for primary care physicians is an important part of our job. Few clinical biochemists (whether medical or scientific) receive significant training for this. Most work in isolation, and few receive feedback on the utility of their comments. Surveys show an extremely wide divergence of opinion and comment even on apparently straightforward sets of abnormal results. Some comments are regarded as highly inappropriate when assessed by peer review. There is a need for further education and training in this area, concentrating as much on 'how to comment' as on 'what to comment'. There is also a need to establish some form of quality assurance for this important part of the post-analytical phase. A pilot External Quality Assurance Scheme (EQAS) is now being established.
Enzyme inhibitory antibody to pyruvate dehydrogenase: diagnostic utility in primary biliary cirrhosis
Authors: Jois Jennifer , Omagari Katsuhisa , Rowley Merrill J , Anderson John , Mackay Ian R
Published: October 2002

In primary biliary cirrhosis, autoantibodies are produced to the family of 2-oxoacid dehydrogenase complexes. These 'anti-mitochondrial' antibodies are traditionally detected by immunofluorescence but this method of detection is subjective and labour-intensive. We assessed an enzymatic mitochondrial antibody (EMA) assay based on antibody inhibition of enzymatic activity of pyruvate dehydrogenase complex in wells of microtitre plates with a colorimetric read-out. We tested 48 Australian and 1947 Japanese patients with primary biliary cirrhosis, 306 normal subjects and 691 patients with various hepatic and non-hepatic diseases. The overall sensitivity of the EMA for the diagnosis of primary biliary cirrhosis, 82%, was slightly lower than that of immunofluorescence, 90% . The advantages of the EMA test include high specificity, > 99% , and semi-automated features facilitating objectivity, rapidity, simplicity and economy. The EMA test could be particularly applicable to population screening for early primary biliary cirrhosis.
Evaluation of effect of analytical imprecision in maternal serum screening for Down's syndrome
Authors: Benn Peter A , Collins Roxanne
Published: October 2002

Formulae to evaluate the effect of inter-assay analytical imprecision (expressed as the coefficient of variation) in maternal serum screening for Down's syndrome have been developed. Experimentally determined imprecision in Down's syndrome risk (based on maternal serum α-fetoprotein, unconjugated oestriol and human chorionic gonadotrophin) was found to be consistent with predicted values. Imprecision in the measurement of analytes becomes amplified when risk is calculated using the values of these analytes. A large separation between the means and small standard deviations for normal and affected pregnancies are the characteristics of the tests most useful in screening, but these attributes also result in the most imprecision in risk. In addition, the relative imprecision associated with Down's syndrome risk is not the same for all women screened. Combining tests for multivariate analyses results in a complex compounding of the errors. The need for strict quality control and test reproducibility is emphasized. The effect of analytical imprecision should be of particular concern to laboratories that provide screening for women of advanced maternal age.
Identification of an apolipoprotein(e) variant associated with type III hyperlipoproteinaemia in an indigenous Australian
Authors: Tate Jillian R , Hoffmann Michael M , Lovelock Paul K , Kesting Janine B , Shaw Joanne T
Published: October 2002

As a result of testing for lipid and apolipoprotein(e) (apo E) phenotype status of an indigenous Australian community, an apo E variant associated with type III hyperlipoproteinaemia has been identified. Apo E phenotype was determined by analysis of VLDL by isoelectric focusing, and genotype on DNA amplified by polymerase chain reaction, using two different restriction enzyme isotyping assays. Phenotypes and genotypes were discordant in samples from two subjects and an abnormal-sized restriction fragment was also observed in their genotyping gel patterns. DNA sequencing studies revealed this was due to a single nucleotide deletion, 3817delC, at amino acid 136 on apo E. This resulted in a new reading frame and the premature termination of the apo E protein due to a stop codon (TGA) at nucleotide 4105. The variant apo E null allele showed a recessive mode of inheritance and, in combination with the E2 allele, resulted in the type III hyperlipoproteinaemic phenotype but when inherited with the E4 allele had no marked effect on plasma lipids.
Effect of storage of plasma and serum on enzymatic determination of non-esterified fatty acids
Authors: Menéndez Luis García , Fernández Ana L , Enguix Alfredo , Ciriza Constanza , Amador Juan
Published: October 2002

Many contradictory results have been published on the stability of total non-esterified fatty acids in blood, plasma and serum under different storage conditions. The present study was undertaken to investigate the stability of non-esterified fatty acids, measured with an enzymatic method, in samples of EDTA-treated plasma and serum under different temperature conditions. We conclude that EDTA-treated plasma and serum can both be used for analysis. Specific reference values should be established depending on the type of sample chosen. Samples that cannot be analysed immediately can be stored at -20°C for at least 14 days without significant changes in the concentration of total non-esterified fatty acids. None of the other storage conditions and periods studied are suitable for the measurement of non-esterified fatty acid concentration.
Effects of renal sorbitol accumulation on urinary excretion of enzymes in hyperglycaemic rats
Authors: Ishii Naohito , Ikenaga Hideki , Ogawa Zensuke , Aoki Yoshikazu , Saruta Takao , Suga Tetsuya
Published: October 2002

We studied the effects of epalrestat, a specific inhibitor of aldose reductase, on renal sorbitol accumulation and the resulting urinary enzyme excretion in hyperglycaemic rats.

The activities of proximal tubule-derived enzymes such as N-acetyl- β-D-glucosaminidase (NAG), alanine aminopeptidase (AAP), γ-glutamyltranspeptidase (GGT) and dipeptidyl aminopeptidase IV (DAPIV) in urine were determined in five groups of male Wistar rats (each n=7): (a) 0·9% saline-loaded, (b) 10% glucose-loaded, (c) 10% glucose-loaded with epalrestat pretreatment, (d) 10% mannitol-loaded and (e) 10% mannitol-loaded with epalrestat pretreatment. Epalrestat was given mixed in chow at a dose of 50mg/kg body weight.

Urinary NAG, AAP, GGT and DAPIV activities were significantly increased ( P<0·005, P<0·05, P<0·01, P<0·01, respectively) by the induction of hyperglycaemia. In contrast, enzyme excretion was not increased in the mannitol- or saline-loaded groups. Pre-treatment with epalrestat completely prevented the increased urinary excretion of NAG, AAP and GGT. At the end of the infusion study, renal cortical glucose concentrations of the glucose-loaded groups with and without epalrestat pretreatment were approximately fivefold higher than those of the mannitol- or saline-loaded groups ( P<0·005 each). Renal cortical sorbitol concentrations of the glucose-loaded group was also approximately twofold higher than those of the mannitol- or saline-loaded groups ( P<0·01 each). However, in the group that received both glucose and epalrestat, renal cortical sorbitol concentration was not increased.

These results suggest that accumulation of intracellular sorbitol leads to proximal tubular cell dysfunction and abnormal enzymuria.
A simple high-pressure liquid chromatography cotinine assay: validation of smoking status in pregnant women
Authors: Greaves R , Trotter L , Brennecke S , Janus E
Published: October 2002

Smoking during pregnancy is a significant public health issue, and studies of the effectiveness of interventions to reduce maternal smoking require accurate measurement of smoking status. This study addresses some key issues in improvement of the effectiveness and efficiency of chemical validation of smoking status using a simplified high-pressure liquid chromatography urine cotinine method.

Urine samples were collected from pregnant women enrolled in a smoking cessation trial and from non-pregnant volunteers exposed to environmental tobacco smoke (ETS). Analysis of ETS samples produced a maximum cotinine of 28 µg/ mmol creatinine, which was established as the cut-off point for this method.

This method is a relatively fast and inexpensive technique with which to analyse large batches of cotinine samples and can reliably measure smoking status.
Synthetic peptide-based electrochemiluminescence immunoassay for anti-Borna disease virus p40 and p24 antibodies in rat and horse serum
Authors: Yamaguchi Kazunari , Sawada Takashi , Yamane Sumitaka , Haga Seiichi , Ikeda Kazuhiko , Igata-Yi Ruriko , Yoshiki Keiko , Matsuoka Masao , Okabe Hiroaki , Horii Yoichiro , Nawa Yukifumi , Waltrip Royce W , Carbone Kathryn M
Published: October 2002

Borna disease virus (BDV) is a neurotropic pathogen that infects a wide variety of vertebrates. We have developed a new electrochemiluminescence immunoassay (ECLIA) for the detection of antibodies to BDV, using three synthetic peptides corresponding to the amino acid residues 3-20 and 338-358 of p40 and 59-79 of p24 peptide of BDV. Using the ECLIA, we examined serum samples for the presence of anti-BDV antibodies in 20 rats (experimentally BDV-infected and uninfected) and 38 horses (13 US horses, experimentally infected and uninfected, and 25 Japanese horses, feral and domestic).

The ECLIA, performed in a double-blind manner, detected anti-BDV antibodies in rats with a history of BDV infection, giving results that were in agreement with indirect immunofluorescence assay and/or Western blot (WB) analysis. The ECLIA also correctly identified all three experimentally infected horses and four domestic American horses that were seropositive for BDV antibodies by WB. Among the Japanese horses, at least two out of 10 feral and six out of 15 domestic horses were seropositive for BDV. In most of these cases, the specificity of immunoreactivity was verified by blocking with soluble p40 and p24 peptides.
Monoclonal IgM: difficulties with correct measurement
Authors: Bossuyt X , Vranken G , Mariën G , Blanckaert N
Published: October 2002

We describe three monoclonal IgM paraproteins for which nephelometric IgM quantification generated inaccurate results.
Limitation of the VitrosTM dry-slide technique in measuring high concentrations of salicylate in plasma
Authors: Iversen S A , Walker A , Avades T Y , Wilson J F
Published: October 2002

The linearity of the VitrosTM dry-slide method for plasma salicylate was assessed in two ways: serial concentrations of sodium salicylate were added to fresh lithium heparin plasma, and the salicylate was determined both neat and in dilution. Vitros salicylate results submitted to the Heathcontrol External Quality Assessment Scheme were compared to the spike value. Similar loss of linearity was observed in both cases. Serious salicylate overdosage requiring specific clinical treatment may have been underestimated.
Bisphosphonates: an overview with special reference to alendronate
Authors: Vasikaran Samuel D
Published: October 2002

Bisphosphonates, analogues of pyrophosphate, are potent inhibitors of osteoclast-mediated bone resorption. They are used in the treatment of Paget's disease of bone, hypercalcaemia and osteolytic bone disease of malignancy, primary and secondary hyperparathyroidism, and in osteoporosis. Bisphosphonate treatment causes an early reduction in bone resorption followed by a later reduction in bone formation. The early inhibition of bone resorption induces a reduction in serum calcium which leads to increased parathyroid hormone (PTH), and subsequently an increase in 1,25-dihydroxyvitamin D. The secondary hyperparathyroidism of bisphosphonate treatment also leads to urinary calcium conservation and phosphaturia, and a reduction in serum phosphate. The increase in the PTH following bisphosphonate therapy is a response to the change in serum calcium and can occur even when there is hypercalcaemia, and this can cause confusion in the interpretation of PTH results. The hypocalcaemic response to bisphosphonates is occasionally severe, especially in patients with hypoparathyroidism. The recent elucidation of bisphosphonate action at the cellular level on the mevalonate pathway has led to interest in its effects on lipoprotein metabolism, which may prove to be of clinical significance. Newer and more potent bisphosphonates are currently undergoing clinical trials in malignant bone disease and osteoporosis, and will lead to further advances in the optimal management of these conditions.
Determination of plasma free carnitine by electrospray tandem mass spectrometry
Authors: Hardy David T , Preece Mary Anne , Green Anne
Published: October 2002

We have evaluated a tandem mass spectrometry method for determining free carnitine concentrations in plasma and have compared its performance with that of an existing radioenzymatic assay. In this method, plasma was mixed with an internal standard, carnitine-d3 (600 nmol/L), and butylated before analysis on a Quattro II tandem mass spectrometer.

The detection limit of the tandem mass spectrometric (MS) method was 4 µmol/L and carryover between samples was 2·2%. Precision of the method was 1·6-5·4% between injections and 4·0-5·6% between samples. Between-batch precision was 10-13%.

The method was linear up to a free carnitine concentration of 300 µmol/L and good agreement was found with the existing radioenzymatic assay.

We conclude that the tandem MS method is a precise and robust method for the determination of free carnitine concentrations in plasma that overcomes the disadvantages of the radiochemical method.
Molecular analysis of a Thai β-thalassaemia heterozygote with normal haemoglobin A2 level: implication for population screening
Authors: Fucharoen Supan , Fucharoen Goonnapa , Sanchaisuriya Kanokwan , Pengjam Yutthana
Published: October 2002

Background This study aimed to characterize the molecular basis of a β-thalassaemia heterozygote who had a normal haemoglobin A2 level. Methods Using haematological and molecular analyses, the -α and β-globin genotypes in a Thai woman with normal haemoglobin A2 level, who was identified in a thalassaemia and haemoglobinopathy screening programme, were examined. Results The patient was positive for a 0·36% one-tube osmotic fragility test but negative for the dichlorophenolindophenol dye test for haemoglobin E. Haemoglobin A and A2 were observed on cellulose acetate electrophoresis with the haemoglobin A2 of 2·0%, compatible with an α-thalassaemia 1 carrier. Polymerase chain reaction analysis failed to detect α-thalassaemia 1 (South East Asian deletion). β-globin gene analysis detected a severe βo-thalassaemia allele with the 4 bp (-CTTT) deletion at codons 41/42. Further analysis of the-globin gene identified the homozygosity of the 3·7 kb deletion α-thalassaemia 2. Conclusions The patient was found to be an unusual case: a βo-thalassaemia carrier with a low haemoglobin A2 concentration, in combination with a homozygosity for the 3·7 kb α-thalassaemia 2 deletion. The approach used to characterize the patient and the result obtained in this report will prove useful for population screening of thalassaemia in regions where both α- and β-thalassaemias are common.
Interpretation of plasma brain natriuretic peptide concentrations may require adjustment for patient's age
Authors: Nageh Thuraia , Chin Derek , Cooke Jennifer C , Meehan Noreen , Monaghan Mark J , Sherwood Roy A
Published: October 2002

Background: Brain natriuretic peptide (BNP) is increasingly recognized as a practical, reliable and accurate indicator of left ventricular function and may have an important prognostic role in determining outcome following myocardial infarction and heart failure. Methods and Results: We studied a total of 60 patients referred for dobutamine-stress echocardiography to evaluate possible reversible myocardial ischaemia. There was no echocardiographic evidence of structural or functional heart disease in any of the patients included in the study. Blood was sampled for BNP at rest, prior to dobutamine-stress. We found a significant linear correlation between BNP concentrations and patients' age, in the absence of structural or functional heart disease ( rs=0.53, 95%CI 0.25-0.73, P<0.0001). Conclusion: Our observations suggest the need for consideration of patient's age when interpreting BNP concentrations in the population.
Diurnal variation in lipoprotein lipase activity
Authors: Arasaradnam MP , Morgan L , Wright J , Gama R
Published: October 2002

Background: We investigated whether variations in lipoprotein lipase activity, a key post-prandial enzyme involved in the removal of circulating dietary triglycerides, could contribute to the previously described nocturnal lipid intolerance. Methods: We studied lipoprotein lipase activity in 12 healthy volunteers (five women, seven men) at 11.30 h and 23.30 h on two separate occasions. Subjects consumed a high-fat mixed meal at 07.30 h for the morning study or 19.30 h for the evening study. Then, after a 4-h fast, subjects were given an intravenous bolus of 7500 U heparin. Blood samples were collected before and 15 min after heparin administration for measurement of lipoprotein lipase, hepatic lipase, triglycerides and non-esterified fatty acids concentrations. Results: Post-prandial post-heparin lipoprotein lipase activity was greater in the morning than in the evening (16.5±1.4 versus 14.4±1.0 µmol oleate/mL/h; P<0.05). Post-prandial post-heparin hepatic lipase activity was also greater in the morning than in the evening (8.7±1.5 versus 8.1±1.6 µmol oleate/mL/h; P=0.002). There were no other significant diurnal differences. Conclusion: We report a diurnal variation in post-prandial lipoprotein lipase activity. This is consistent with the notion that decreased nocturnal insulin sensitivity extends to insulin's actions on lipoprotein lipase and provides a possible explanation for nocturnal lipid intolerance.
Effect of ageing on plasma lipoprotein(a) levels
Authors: Akita Harukuni , Matsubara Miyao , Shibuya Hitoshi , Fuda Hirotoshi , Chiba Hitoshi
Published: October 2002

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.
LDL-cholesterol and HDL-cholesterol concentrations decrease during the day
Authors: Miida Takashi , Nakamura Yuichi , Mezaki Toru , Hanyu Osamu , Maruyama Seitaro , Horikawa Yoshinori , Izawa Sachiko , Yamada Yukio , Matsui Hiroshi , Okada Masahiko
Published: October 2002

Background Homogenous assays for LDL-cholesterol (LDL-C) and HDL-cholesterol (HDL-C) are highly accurate, with little interference from triglyceride. Using these methods, we measured postprandial LDL-C and HDL-C. Earlier studies suggested a postprandial decrease in LDL-C. Methods To elucidate whether LDL-C and HDL-C decrease significantly during the day, we determined daily profiles of LDL-C and HDL-C using homogeneous assays in subjects with normal coronary arteries (N; n = 10), and subjects with coronary artery disease (CAD; n = 23). Results In both groups, LDL-C and HDL-C were significantly lower from after breakfast until midnight than they were before breakfast. The next morning, they returned to baseline levels. The mean reduction in LDL-C was 0·09--0·13 mmol/L in N and 0·05--0·20 mmol/L in CAD, while that in HDL-C was 0·02--0·06 mmol/L in N and 0·00--0·05 mmol/L in CAD. Conclusion LDL-C and HDL-C decrease significantly over the course of the day.
Application of computer simulation analysis to assess the effects of relocating a hospital phlebotomy department
Authors: Groothuis Siebren , Goldschmidt Henk MJ , Drupsteen Esther J , de Vries Jules CM , Hasman Arie , van Merode Godefridus G
Published: October 2002

Background This study describes a systematic approach to assess the effects of relocating a hospital department. Methods Using the phlebotomy service as an example, computer simulation was applied to predict changes in performance indicators, such as patient turn-around time (TAT), when planning a procedural and/or architectural redesign. Results Average patient TAT fell from 12 to 8 min, enabling the department to cope with any increase in numbers of patients. Conclusion This type of study can provide useful information in assessing the consequences of future changes in the location of a hospital department.
Determination of the isoflavonoids genistein and daidzein in biological samples by gas chromatography-mass spectrometry
Authors: Pumford Sara L , Morton Michael M , Turkes Atilla , Griffiths Keith
Published: October 2002

Background The marked differences in the incidences of both breast and prostate cancer between the East and the West have been attributed to habitual diet. Traditionally, Japanese and Far Eastern people in general consume large quantities of soya and soya-derived foodstuffs. Diphenolic soya phytoestrogens have weak oestrogenic and anti-oestrogenic properties and have been implicated in preventing or limiting the early processes associated with breast and prostate carcinogenesis. Methods We have developed a gas chromatography-mass spectrometry procedure that is suitable for measurement of the phytoestrogens daidzein and genistein in serum, urine and tissue samples. Results In serum samples of Japanese subjects mean (standard deviation) concentrations of daidzein [men, 281 (375·5) nmol/L; women, 246 (369·4) nmol/L] and genistein (men, 493 (604·4) nmol/L; women, 502 (717·6) nmol/L] were approximately 15 times higher than the mean levels achieved in British men [daidzein, 18·2 (20·4) nmol/L; genistein, 34·1 (27·2) nmol/L] and women [daidzein, 13·5 (11·6) nmol/L; genistein, 30·1 (31·2) nmol/L]. In pharmacokinetic studies of British subjects, maximum levels of daidzein and genistein were achieved within 6-8 h after the consumption of a cereal bar containing 20 mg of soya isoflavonoids; these levels were very similar to the mean levels achieved in normal Japanese subjects. Unlike serum, the mean daidzein concentration in urine from British subjects was higher than the mean genistein concentration (1·66 and 0·72 μmol per 24 h, respectively); following soy supplementation, urinary isoflavonoid levels were increased at least 10-fold. Conclusions Serum daidzein and genistein concentrations are lower in British subjects than in Japanese subjects; this may be due to dietary differences.
Monitoring mycophenolic acid
Authors: Holt David W
Published: October 2002

The immunosuppressive agent mycophenolate mofetil is a prodrug for the active compound mycophenolic acid. Following organ transplantation, it is used mostly in combination with other immunosuppressive drugs, but it has also been used as primary therapy. Although in the pivotal clinical studies the drug was given in fixed doses, there has been substantial interest in the measurement of mycophenolic acid in plasma as a guide to optimizing therapy. Data have emerged which indicate that the metabolism of the compound is more complex than was originally thought and that variability in exposure to the drug, assessed by area under the time-concentration curve, is an important determinant of efficacy. This article highlights basic pharmacokinetic and pharmacodynamic data for mycophenolic acid, which underlie the rationale for its measurement. These data are then set in the context of providing a routine service for the measurement of the drug with either of the analytical techniques currently available - immunoassay or high performance liquid chromatography. There are a number of issues regarding the clinical interpretation of mycophenolic acid measurements which are yet to be resolved. Centres contemplating the introduction of such a service will need to keep abreast of a rapidly evolving literature.
Can we measure serum thyroglobulin?
Authors: Clark PM , Beckett G
Published: October 2002

Measurement of serum thyroglobulin (Tg) by immunoassay is used to monitor the treatment of differentiated thyroid cancer. An understanding of the disease process and the biochemistry of Tg allows the laboratory to determine the characteristics of suitable Tg assays. There are a number of key analytical issues: standardization, long-term assay stability, minimum detection limit, working range and the effect of endogenous Tg antibodies (TgAb). There are significant limitations to the methods used to determine TgAb interference. Clinicians should be aware of the limitations of immunoassays for this tumour marker.
Serum transferrin receptor assays and their application
Authors: Worwood Mark
Published: October 2002

Most cells acquire iron from plasma transferrin and it is the transferrin receptor that is responsible for the internalization of transferrin-bound iron and its subsequent intracellular release. Plasma concentrations of the receptor reflect cellular receptor numbers and may be determined by enzyme immunoassay on automated analysers. Although determination of receptor concentrations may provide little additional value to existing measures of iron status, particular circumstances may dictate the use of these assays. This review summarizes transferrin receptor physiology and biochemistry, the limitations of the methodology that is currently available and the clinical application of assays (a) in monitoring changes in the rate of erythropoiesis, (b) as an indicator of developing iron deficiency and (c) in identifying iron deficiency in patients with anaemia of chronic disease.
Clinical governance: implications for point-of-care testing
Authors: Freedman Danielle B
Published: October 2002

With the introduction of clinical governance in the UK during 1997 and the shift in focus from a purely financial perspective to one of quality, it has become even more important that laboratories become involved with in vitro diagnostic devices (IVDs) used outside the laboratories by non-laboratory personnel, namely, point-of-care testing (POCT). The demand for POCT is increasing and its growth will continue with advances in technology, increasing pressure to shorten patient length of stay and requirements to decrease turnaround times, alongside the national initiatives to consolidate laboratories. However, clinical governance is about practising evidence-based medicine, and both the clinical and cost-effectiveness of POCT continue to be debated. Accountability and leadership are pivotal in the implementation of clinical governance. Thus, the onus is on laboratories to take the lead for POCT and ensure that there is a robust risk management strategy to protect not only the staff, but, importantly, the patient. A rigorous POCT policy and national guidance must be adhered to. For a high quality POCT service to be delivered, fulfilling the requirements of clinical governance, a multidisciplinary local group must be established with recognized accountability, appropriate resources and, importantly, management support.
Pregnancy and inherited metabolic disorders: maternal and fetal complications
Authors: Preece Mary Anne , Green Anne
Published: October 2002

Some inherited metabolic disorders (IMDs) can cause significant complications during pregnancy, affecting the mother and/or the fetus. Although it appears that only a minority of IMDs have these effects, experience is still being acquired. For some disorders, patients will not have reached child-bearing age. Pregnancies in this group of patients will increase as the management of IMDs in childhood and adolescence improves. Clinicians should be aware of potential complications and consider carefully how best to manage these conditions. Ideally, patients should be followed up in adult life by a specialized clinical team, which can implement a planned approach to conception and pregnancy, but often this is not possible. For disorders where the risk of complications is well established (e.g. phenyl-ketonuria), optimal treatment may lead to a good fetal and maternal outcome. It is important also to consider the possibility of an IMD being present in fetuses of pregnancies that are affected by non-immune hydrops, maternal HELLP syndrome (haemolysis, elevated liver enzymes and low platelets) or acute fatty liver of pregnancy.
Near-patient testing of blood glucose using the Bayer Rapidlab 860 analyser in a regional neonatal unit
Authors: Peet Andrew C , Kennedy David M , Hocking Michael D , Ewer Andrew K
Published: October 2002

Background: We evaluated the use of the glucose biosensor on the Bayer Rapidlab 860 (BR 860) blood gas analyser for neonates and compared it with two laboratory-based methods for measuring blood glucose using the Yellow Springs Instruments 2300 STAT PLUS (YSI) analyser and the Vitros 750 XRC (Vitros) analyser.

Methods: Arterial, capillary and venous blood samples were taken from 50 neonates, and blood glucose was measured using all three instruments. Blood pH, PO2, haematocrit and plasma albumin data were also recorded. The effect of varying the degree of haemolysis and the haematocrit was examined using cord blood samples prepared in vitro.

Results: Day-to-day imprecision of the BR 860 was 4·90% at a mean glucose concentration of 2·55 mmol/L ( n=60), compared with 3·03% at 2·33 mmol/L ( n=34) for the YSI and 2·64% at 3·52 mmol/L for the Vitros ( n=59). Using Deming regression, the BR 860 results correlated well with results produced on both the YSI ( r=0·962, n=47, P<0·001) and Vitros ( r=0·980, n=46, P<0·001) analysers. Bland-Altman difference plots showed that the BR 860 had a mean of the differences of 0·30 mmol/L compared with the YSI and 0·09 mmol/L compared with the Vitros. The Bland-Altman standard deviation of the differences was 0·46 mmol/L when the BR 860 was compared with the YSI and 0·31 mmol/L when the BR 860 was compared with the Vitros. No significant correlation was found between the BR 860 glucose measurements and haematocrit, degree of sample haemolysis, plasma albumin, blood pH or PO2.

Conclusions: The BR 860 analyser provides neonatal blood glucose measurements in the clinical setting of a neonatal unit that compare well with results obtained using laboratory-based methods.