Clinical Chemistry back issues from September 2007:
High-Throughput, Automated, and Accurate Biochemical Screening for Pheochromocytoma: Are We There Yet?
Sep 01, 2007; ... Biochemical testing for pheochromocytoma is a diagnostic challenge due both to the highly variable nature of this rare catecholamine-producing tumor and the technical demands required for accurate and reliable laboratory tests of catecholamine excess. In this issue of Clinical Chemistry, de Jong ...
Development of an Integrated Assay for Detection of BCR-ABL RNA
Sep 01, 2007; ... Background: Current practice guidelines for managing patients with chronic myelogenous leukemia (CML) call for monitoring BCR-ABL transcript concentrations with a quantitative reverse transcription-PCR (qRT-PCR) assay. Because the available laboratory-developed assays lack consensus on the ...
Molecular Diagnosis of Wilson Disease Using Prevalent Mutations and Informative Single-Nucleotide Polymorphism Markers
Sep 01, 2007; ... Background: Wilson disease (WD) is an autosomal recessive disorder caused by defects in the ATPase, Cu^sup 2+^ transporting, β-polypeptide gene (ATP7B) resulting in accumulation of copper in liver and brain. WD can be thwarted if detected at a presymptomatic stage, but occasional ...
Polymorphisms within the Protein Tyrosine Phosphatase 1B (PTPN1) Gene Promoter: Functional Characterization and Association with Type 2 Diabetes and Related Metabolic Traits
Sep 01, 2007; ... Background: Protein tyrosine phosphatase 1B (PTPN1) dephosphorylates insulin receptors and attenuates insulin signaling. Polymorphisms in the coding sequence of PTPN1 have been variably associated with type 2 diabetes (T2D). We hypothesized that variations within the PTPN1 promoter might ...
Specific Magnetic Bead-Based Capture of Genomic DNA from Clinical Samples: Application to the Detection of Group B Streptococci in Vaginal/Anal Swabs
Sep 01, 2007; ... Background: Group B streptococci (GBS) are a leading cause of sepsis and meningitis in newborns. We previously developed a rapid diagnostic system for GBS detection from vaginal/anal samples obtained from pregnant women during delivery. To facilitate the adaptation of this method for ...
Introducing Single-Nucleotide Polymorphism Markers in the Diagnosis of Wilson Disease
Sep 01, 2007; ... Wilson disease (WD) represents a monogenic disease resulting in copper accumulation within tissues. Incidence is estimated to be approximately 1:30 000. Symptoms include acute and chronic liver disease, hemolysis, and neurodegenerative and psychiatric symptoms (1). The first symptom may be acute ...
A Simple and Robust Quantitative PCR Assay to Determine CYP21A2 Gene Dose in the Diagnosis of 21-Hydroxylase Deficiency
Sep 01, 2007; ... Background: Correct diagnosis of 21-hydroxylase deficiency (21OHD) requires the identification of CYP21A2 gene deletions and CYP21A1P/CYP21A2 chimeric genes, which are disease-causing alleles, and gene duplications, which can lead to false-positive 21OHD allele results. Because lack of suitable ...
Protein:Creatinine Ratio in Random Urine Samples Is a Reliable Marker of Increased 24-Hour Protein Excretion in Hospitalized Women with Hypertensive Disorders of Pregnancy
Sep 01, 2007; ... Background: The protein:creatinine ratio in random, untimed urine samples correlates with 24-h protein excretion in pregnant women with and without hypertension. Nevertheless, whether this ratio is appropriate as a screening test for proteinuria is still unclear, in part because of the paucity ...
Laboratory Testing for Lupus Anticoagulants: A Review of Issues Affecting Results
Sep 01, 2007; ... Background: Lupus anticoagulants (LA) are a heterogeneous class of immunoglobulins. Persistent LA positivity is a risk factor for the occurrence and recurrence of venous/arterial thromboembolism and/or pregnancy morbidity and qualifies the patient for anticoagulation therapy. The laboratory ...
Characterization of Diabetic Nephropathy by Urinary Proteomic Analysis: Identification of a Processed Ubiquitin Form as a Differentially Excreted Protein in Diabetic Nephropathy Patients
Sep 01, 2007; ... Background: Identification of markers for prediction of the clinical course of diabetic nephropathy remains a major challenge in disease management. We established a proteomics approach for identification of diabetic nephropathy-related biomarkers in urine. Methods: We used SELDI-TOF ...
Standardization of ROC Curve Areas for Diagnostic Evaluation of Liver Fibrosis Markers Based on Prevalences of Fibrosis Stages
Sep 01, 2007; ... Background: The area under the ROC curve (AUC) is widely used as an estimate of the diagnostic value for fibrosis markers. Whether there is variability in the AUC related to the prevalence of fibrosis stages defining advanced and nonadvanced fibrosis is unknown. The aim of this study was to ...
Increased Concentrations of Antibody-Bound Circulatory Cell-Free DNA in Rheumatoid Arthritis
Sep 01, 2007; ... Background: Increased concentrations of cell-free DNA have been found in several disorders and have been interpreted as evidence of increased rates of cell death or turnover. Evidence from in vitro and animal experiments suggests that DNA may play a role in the pathogenesis of rheumatoid ...
A Novel Method to Capture Methylated Human DNA from Stool: Implications for Colorectal Cancer Screening
Sep 01, 2007; ... Background: Assay of methylated DNA markers in stool is a promising approach for colorectal cancer (CRC) screening. A method to capture hypermethylated CpG islands from stool would enrich target analyte and allow optimal assay sensitivity. Methods: Methyl-binding domain (MBD) protein was ...
Oxidative Stress Markers Are Associated with Persistent Atrial Fibrillation
Sep 01, 2007; ... Background: Atrial fibrillation (AF) has been associated with myocardial oxidative stress, and antioxidant agents have demonstrated antiarrhythmic benefit in humans. We compared serum markers of oxidation and associated inflammation in individuals with or without AF. Methods: Serum ...
Second-Trimester Reference Intervals for Thyroid Tests: The Role of Ethnicity
Sep 01, 2007; ... Background: Thyroid function changes during pregnancy, complicating the diagnosis of thyroid disorders. Maternal thyroid dysfunction has been associated with a variety of adverse outcomes. We evaluated thyroid function test results by ethnicity and week of gestation during the 2nd trimester of ...
Improving Healthcare Accessibility through Point-of-Care Technologies
Sep 01, 2007; ... Background: The NIH is committed to improving healthcare quality in the US and has set up initiatives to address problems such as the fragmented nature of healthcare provision. A hypothesis has been developed that testing closer to the point at which care is delivered may reduce fragmentation of ...
Quantification of Diphtheria Toxin-Mediated ADP-Ribosylation in a Solid-Phase Assay
Sep 01, 2007; ... Background: Because of reduced vaccination programs, the number of diphtheria infections has increased in the last decade. Diphtheria toxin (DT) is expressed by Corynebacterium diphtheriae and is responsible for the lethality of diphtheria. DT inhibits cellular protein synthesis by ...
Plasma Free Metanephrine Measurement Using Automated Online Solid-Phase Extraction HPLC-Tandem Mass Spectrometry
Sep 01, 2007; ... Background: Quantification of plasma free metanephrine (MN) and normetanephrine (NMN) is considered to be the most accurate test for the clinical chemical diagnosis of pheochromocytoma and follow-up of pheochromocytoma patients. Current methods involve laborious, time-consuming, offline sample ...
Certification of Creatinine in a Human Serum Reference Material by GC-MS and LC-MS
Sep 01, 2007; ... Background: To meet recommendations given by the Laboratory Working Group of the National Kidney Disease Education Program for improving serum creatinine measurements, NIST developed standard reference material (SRM) 967 Creatinine in Frozen Human Serum. SRM 967 is intended for use by ...
T-Cell Regulatory Gene CTLA-4 Polymorphism/Haplotype Association with Autoimmune Pancreatitis
Sep 01, 2007; ... Background: Autoimmune pancreatitis (AIP) is a distinct disease entity of chronic pancreatitis. Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is a key negative regulator of the T-cell immune response, and its gene is highly polymorphic. Many positive associations between cytotoxic ...
HPLC Method for Plasma Vitamin K^sub 1^: Effect of Plasma Triglyceride and Acute-Phase Response on Circulating Concentrations
Sep 01, 2007; ... Background: The plasma concentration of vitamin K^sub 1^ (phylloquinone) is the most reliable index for assessing vitamin K status. Our aim was to analytically validate an HPLC method for quantifying phylloquinone in plasma and to examine the effect of plasma triglyceride concentration on the ...
Spurious Conclusions on Analog Free Thyroxine Assay Performance
Sep 01, 2007; ... To the Editor: I read with misgivings the recent communication by Fritz et al. (1) alleging that because under some circumstances an analog free thyroxine (FT^sub 4^) immunoassay correlates total T^sub 4^ and FT^sub 4^ values, it does not measure FT^sub 4^ but something akin to T^sub 4^ ....
Presence of the Hemochromatosis S65C Mutation Leads to Failure of Amplification in a Multiplex C282Y/H63D PCR
Sep 01, 2007; ... To the Editor: Hemochromatosis is an autosomal recessive disorder of iron metabolism affecting 0.2%-0.5% of white populations. Approximately 90% of affected individuals are homozygous for the C282Y mutation, but the H63D and S65C mutations are also of interest. Various molecular ...
A Recommended Improvement for Specifying and Estimating Serum Creatinine Performance/The authors of the article cited above respond
Sep 01, 2007; ... To the Editor: Myers et al. (1) discuss the importance of creatinine analytical performance in the estimation of the glomerular filtration rate. They correctly specify a model of assay performance but subsequently do not seem to use that model. I suggest a variation of their model that ...
Measurements of Free Hemoglobin and Hemolysis Index: EDTA- or Lithium-Heparinate Plasma?
Sep 01, 2007; ... There is no agreement as to the optimal sample type to be used for measurements of free hemoglobin (fHb) in plasma. (Because fHb is increased during clotting, serum is not recommended.) Several publications have recommended the use of EDTA as an anticoagulant (2 ), but another author reported ...
Comparison of the Diagnostic Accuracy of BNP and NT-proBNP in Acute and Chronic Heart Failure/The authors of the article cited above respond
Sep 01, 2007; ... To the Editor: I read with great interest the paper by Clerico et al. (1), which described a comparable diagnostic accuracy of brain natriuretic peptide (BNP) and the N-terminal part of the propeptide of BNP (NT-proBNP) in patients with heart failure. The authors are to be congratulated ...
Genetic Factors for Warfarin Dose Prediction
Sep 01, 2007; ... To the Editor: Warfarin, a commonly prescribed anticoagulant drug used to prevent thrombosis, has a narrow therapeutic range, and small dose variations may result in hemorrhagic or thrombotic complications. The 2 key enzymes in the metabolism of warfarin are cytochrome P450 (CYP) 2C9 ...
Evaluation of Analytical Performance of the Siemens ADVIA TnI Ultra Immunoassay
Sep 01, 2007; ... To the Editor: In light of recommendations on the quality (1) and clinical use (2) of troponin assays, we evaluated the analytical performance of the ADVIA Centaur and ADVIA CP® platforms (Tnl-Ultra, Siemens Medical Solutions Diagnostics SrL) for measurement of cardiac troponin I (cTnl) ....
Midtrimester Amniotic Fluid Adiponectin in Normal Pregnancy
Sep 01, 2007; ... To the Editor: Adiponectin is an adipose tissue-derived protein with important metabolic effects and a strong correlation with insulin sensitivity. In pregnancy there is a progressive increase of insulin resistance, whereas plasma adiponectin concentrations decrease in the 2nd half of ...
Correction
Sep 01, 2007; ... In the article entitled "Diagnosis of a-1-Antitrypsin Deficiency: An Algorithm of Genotyping, Phenotyping, and Quantitation" by Melissa R. Snyder, Jerry A. Katzmann, Malinda L. Butz, Ping Yang, D. Brian Dawson, Kevin C. Hailing, W. Edward Highsmith, and Stephen N. Thibodeau (Clin Chem ...
Hemoglobin Hagley Park: A Novel ([alpha]82Ala[arrow right]Thr) Substitution Identified in an Infant with Severe Hemolytic Anemia
Sep 01, 2007; ... To the Editor: The identification of new hemoglobin mutations and the correlation of structural changes with potential pathology continue to provide insights into how normal structure and function are preserved in the tetrameric molecule. Hematological investigation of a ...