bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of Cardiac Natriuretic Hormones (Atrial Natriuretic Peptide, Brain Natriuretic Peptide, and Related Peptides) in Clinical Practice: The Need for a New Generation of Immunoassay Methods
Authors: Clerico Aldo , Del Ry Silvia , Giannessi Daniela
Published: January 2020

Background: Cardiac natriuretic hormones (CNHs) are a family of related peptides, including atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and other peptides derived from the N-terminal portion of the proANP and proBNP peptide chains. Assays for cardiac natriuretic peptides have been proposed to help assess clinical conditions associated with expanded fluid volume. In particular, the assays can be useful for distinguishing healthy subjects from patients in different stages of heart failure. Measurements of these hormones have also been considered for prognostic indicators of long-term survival in patients with heart failure and/or after acute myocardial infarction. The different CNHs differ in their production/secretion patterns and have different clearance rates. Furthermore, there are numerous proposed assay configurations for each of these hormones, and it is not clear which assay provides the best pathophysiological and/or clinical information.

Approach: Here we review recent studies concerning the competitive (such as RIA, enzyme immunoassay, or luminescence immunoassay) and noncompetitive immunoassays (such as two-site IRMA, ELISA, or immunoluminometric assay) for the different cardiac natriuretic peptides to compare the analytical characteristics and clinical relevance of assays for the different CNHs and the different assay formats.

Content: Developing sensitive, precise, and accurate immunoassays for cardiac natriuretic peptides has been difficult because of their low concentrations (on average, ∼3–6 pmol/L) in healthy subjects and because of their structural, metabolic, and physiological characteristics. Competitive assays have historically suffered from lack of sensitivity and specificity for the biologically active peptides. These usually require tedious extraction procedures prior to analysis. Recently, immunometric assays have been developed that have improved sensitivity and specificity; it appears these will be the methods of choice.

Summary: To date, there is no consensus on the best assay procedure of cardiac natriuretic peptides. To facilitate widespread propagation of determination of these hormones in routine clinical practice, it will be necessary to study the new generation of noncompetitive immunometric methods that are less time-consuming and more sensitive and specific. Although several studies suggest that BNP exhibits better clinical utility than the other CNHs, more studies examining multiple CNHs in the same cohorts of patients will be necessary.
Genotypes and Phenotypes for Apolipoprotein E and Alzheimer Disease in the Honolulu-Asia Aging Study
Authors: Kardaun Jan W P F , White Lon , Resnick Helaine E , Petrovitch Helen , Marcovina Santica M , Saunders Ann M , Foley Dan J , Havlik Richard J
Published: January 2020

Background: The utility of apolipoprotein E (ApoE) type as an indicator of genetic susceptibility to Alzheimer disease (AD) depends on the reliability of typing. Although ApoE protein isoform phenotyping is generally assumed equivalent to genotyping from DNA, phenotype-genotype differences have been reported.

Methods: ApoE genotype and phenotype results were examined for 3564 older (ages 71–93 years) Japanese-American male participants of the Honolulu-Asia Aging Study, an ongoing population-based study of aging and dementia.

Results: Both methods demonstrated similar associations of ApoE type with AD: a direct association with ApoE4 and a less dramatic inverse association ApoE2. Advanced age did not appear to influence the ApoE4-AD association. The association with AD among ApoE4 homozygotes [odds ratio (OR) = 14.7] was higher than expected based on an observed OR of 2.0 in heterozygotes. Phenotype-genotype nonconcordance was more frequent for ApoE2 than for ApoE4. The ApoE2 phenotype occurred at a frequency of 7.9% vs a genotype frequency of 4.9%, corresponding to a probability of 56% that an individual with ApoE2 phenotype had the same genotype.

Conclusions: Whereas E4 and E2 phenotypes and genotypes were comparably associated with AD, neither method would be expected to substantially improve the efficiency of case finding in the context of population screening beyond prediction based on age and education. Nonconcordance of phenotype and genotype was substantial for E2 and modest for E4 in this population. The ApoE4-AD association was independent of age.
Plasma Nitric Oxide Concentrations and Nitric Oxide Synthase Gene Polymorphisms in Coronary Artery Disease
Authors: Yoon Yeomin , Song Junghan , Hong Seung H o , Kim Jin Q
Published: January 2020

Background: Plasma NOx (nitrate and nitrite) is a stable end product of the vasodilator NO. Several polymorphisms in the endothelial constitutive NO synthase (ecNOS) gene have been reported, including the 4a/4b VNTR polymorphism in intron 4, the E298D mutation in exon 7, and the G10-T polymorphism in intron 23. The aims of this study were to examine plasma NOx in patients with coronary artery disease (CAD) and to assess the association between plasma NOx concentrations and the three ecNOS gene polymorphisms.

Methods: Plasma NOx was measured in samples from 128 healthy controls and from 110 CAD patients at least 2 months after myocardial infarction. Three genetic polymorphisms that are known or have been suggested to be associated with plasma NOx concentration were also analyzed by PCR-restriction fragment length polymorphism.

Results: Median plasma NOx was significantly higher (P <0.001) in CAD patients (95.9 μmol/L) than in controls (73.8 μmol/L). Furthermore, the median plasma NOx was significantly higher (P <0.001) in hypertensive CAD patients (116.0 μmol/L) than in controls and normotensive CAD patients (86.0 μmol/L). The G-allele frequency of the G10-T polymorphism in intron 23 was significantly higher in CAD patients than in controls. Other polymorphisms showed no differences in allelic frequencies among the control and CAD groups. In controls, individuals with the E298D mutation in exon 7 (136.1 μmol/L) showed significantly higher (P = 0.001) median plasma NOx than those without this mutation (64.5 μmol/L).

Conclusions: Plasma NOx was higher in hypertensive CAD patients than in normotensive CAD patients and controls. The E298D polymorphism of the ecNOS gene was associated with increased plasma NOx. Further study is needed to understand the gene expression and enzyme activity of ecNOS and their association with genotypes.
Comparison of Capillary Electrophoresis with HPLC for Diagnosis of Factitious Hypoglycemia
Authors: Paroni Rita , Comuzzi Barbara , Arcelloni Cinzia , Brocco Stefano , de Kreutzenberg Saula , Tiengo Antonio , Ciucci Alessandra , Beck-Peccoz Paolo , Genovese Stefano
Published: January 2020

Background: The diagnosis of “factitious hypoglycemia” is essentially based on the disclosure of hypoglycemic agents in blood or urine. The aim of this study was to evaluate the performance of capillary electrophoresis (CE) as a quantitative method for determination of chlorpropamide, tolbutamide, glipizide, gliclazide, and glibenclamide in serum.

Methods: Serum samples (1 mL), with internal standard added, were purified by solid-phase extraction on OASISTM HLB cartridges (Waters), dried under reduced pressure, and reconstituted with 30–60 μL of acetonitrile:H2O. Analysis was carried out by micellar electrokinetic capillary chromatography in 5 mmol/L borate, 5 mmol/L phosphate, 75 mmol/L sodium cholate, pH 8.5, containing 25 mL/L methanol. Separation was accomplished in a 20 cm × 50 μm (i.d.) silica capillary at 25 °C and a constant voltage of +10 kV. Pharmacokinetics of gliclazide (80-mg tablet) in a diabetic patient were assayed by both HPLC and CE. Two hypoglycemic patients positive by HPLC analysis for unreported gliclazide and tolbutamide overdose were also screened by CE.

Results: Separation of six drugs (including the internal standard) was accomplished in 5 min plus 5 min rinsing. The between-day CV of the ratio of the areas of the sulfonylurea drugs to internal standard was <1% (n = 10). Linearity (r2 ≥0.998) and recovery (≥80%) were good for all sulfonylurea drugs tested. Pharmacokinetic curves for gliclazide by CE and HPLC were superimposable. CE analysis confirmed the HPLC diagnosis of surreptitious abuse of gliclazide and tolbutamide.

Conclusion: CE is a useful tool in the clinical chemistry and toxicology laboratory for drug monitoring and pharmacokinetic investigations.
Agreement among Four Homocysteine Assays and Results in Patients with Coronary Atherosclerosis and Controls
Authors: Yu Harry H , Joubran Rana , Asmi Muhamad , Law Terence , Spencer Anthony , Jouma Muhidien , Rifai Nader
Published: January 2020

Background: Hyperhomocysteinemia has been associated with coronary atherosclerosis in many, but not all, prospective and retrospective studies. Some on these inconsistencies may be attributed to methodological variabilities.

Methods: In the present study, three newly commercially available assays and one in-house HPLC assay for total homocysteine (tHcy) were utilized in 99 subjects with angiographically documented atherosclerosis and in 91 community controls matched by age, gender, and smoking history. The in-house assay, a modified Fortin and Genest HPLC method, was compared with the Bio-Rad HPLC assay, the Abbott IMx® fluorescence polarization immunoassay, and a Bio-Rad enzyme-linked immunoassay (EIA) microtiter method.

Results: Correlation coefficient values between the in-house HPLC assay and the Bio-Rad HPLC, the Abbott IMx, and the Bio-Rad EIA assays were 0.95, 0.96 and 0.90, respectively. Although tHcy concentrations were higher in cases compared with controls by all four methods, the difference reached statistical significance only with the in-house HPLC procedure (median, 13.5 ± 6.7 μmol/L in cases vs 10.9 ± 4.8 μmol/L in controls; P <0.01, adjusting for covariates), where it was an independent predictor of case or control status, along with hypertension, total cholesterol, and triglycerides. The tHcy distributions in cases and controls demonstrated significant overlap. The number of atherosclerotic major coronary vessels was associated with significantly higher tHcy (P <0.01 for trend) in all four methods.

Conclusions: The three commercial assays for tHcy differed in analytical and clinical performance. Analytically, the Abbott IMx method showed the best comparability with the in-house assay, but clinically, the three commercial methods were similar and did not distinguish cases from controls.
History of Clinical Chemistry in a Children’s Hospital (1914–1964)
Authors: Meites Samuel
Published: January 2020

The historical development of a charitable children’s hospital and the evolution of its clinical laboratory are presented. With the appearance of practical quantitative blood chemistry tests in the period between the two World Wars, applications to pediatrics were hampered by the need for ultramicro procedures then unavailable and for improved skin-puncture blood sampling. World War II brought economic demands that forced the hospital to privatize its beds and to charge fee-for-services. In turn, this brought added income, allowing the hiring or subsidizing of a professional staff, including the clinical chemist. The development of ultramicro blood chemistry followed, along with improved skin-puncture technology.
The Costs of Disease
Authors: Young Donald S , Sachais Bruce S , Jefferies Leigh C
Published: January 2020

Background: To date there have been no studies identifying and comparing the component costs to treat a large number of diseases for hospitalized inpatients.

Methods: Hospital costs were analyzed for 486 diagnosis-related groups (DRGs) relating to >1.3 million patient discharges from 60 University Hospital members of the University HealthSystems Consortium. For each DRG, length of stay, total cost, and key cost components were analyzed, including accommodation, intensive care, and surgery.

Results: In general, total costs of diseases classified as surgical exceeded those classified as medical. Diseases involving organ transplantation typically cost more than other diseases. However, within the studied population, the two DRGs accounting for most total healthcare dollars were percutaneous cardiovascular procedures and management of neonates with immaturity or respiratory failure.

Conclusions: Considering six key cost components, as well as disease complexity and length of stay, the best predictors of total costs for medical conditions were the length of stay and accommodation (housing, meals, nursing services) costs, whereas for surgical conditions, the best predictor of total costs was laboratory costs. This analysis may be used within an individual institution to identify surgical or medical diagnoses with total or component costs at variance with the group mean. A hospital may focus its cost reduction efforts to make decisions to expand, alter, or eliminate particular clinical programs based on comparison of its own total and component costs with those from other hospitals in the database.
Vitamin E and Coronary Heart Disease in Tunisians
Authors: Feki Moncef , Souissi Malek , Mokhtar Elyes , Hsairi Mohamed , Kaabachi Naziha , Antebi Helena , Alcindor Louis Gérald , Mechmeche Rachid , Mebazaa Abderraouf
Published: January 2020

Background: Vitamin E (VE) is thought to be effective in preventing atherosclerosis. However, to date no consistent relationship has been identified between VE and coronary heart disease (CHD). This study was designed to assess the degree of association between VE and CHD in a sample of the Tunisian population.

Methods: Sixty-two angiographically confirmed coronary atherosclerotic patients and 65 age- and sex-matched controls were included. VE was measured in plasma and in the LDL fraction by HPLC. Cholesterol, triglycerides, and phospholipids were measured by enzymatic methods.

Results: A trend toward a meaningful decrease of plasma VE was observed in affected patients compared with controls (P = 0.06). VE concentrations standardized for cholesterol and lipid concentrations were significantly lower (P <0.02) in coronary patients than in controls (4.35 ± 1.03 vs 4.82 ± 1.23 mmol/mol for cholesterol-adjusted VE and 2.35 ± 0.56 vs 2.66 ± 0.65 mmol/mol for lipid-adjusted VE, respectively). In the LDL fraction, only cholesterol-standardized VE was significantly lower in cases than controls (3.84 ± 1.13 vs 4.41 ± 1.16 mmol/mol). This association between VE and CHD remained unchanged independent of age, sex, smoking habit, hypertension, and diabetes. In CHD patients, lower lipid-adjusted VE was associated with enhanced LDL susceptibility to oxidation but without alteration of the serum fatty acid profile.

Conclusions: These results support the hypothesis that VE plays a role in preventing atherosclerosis.
Computer-supported Detection of M-Components and Evaluation of Immunoglobulins after Capillary Electrophoresis
Authors: Jonsson Magnus , Carlson Joyce , Jeppsson Jan-Olof , Simonsson Per
Published: January 2020

Background: Electrophoresis of serum samples allows detection of monoclonal gammopathies indicative of multiple myeloma, Waldenström macroglobulinemia, monoclonal gammopathy of undetermined significance, and amyloidosis. Present methods of high-resolution agarose gel electrophoresis (HRAGE) and immunofixation electrophoresis (IFE) are manual and labor-intensive. Capillary zone electrophoresis (CZE) allows rapid automated protein separation and produces digital absorbance data, appropriate as input for a computerized decision support system.

Methods: Using the Beckman Paragon CZE 2000 instrument, we analyzed 711 routine clinical samples, including 95 monoclonal components (MCs) and 9 cases of Bence Jones myeloma, in both the CZE and HRAGE systems. Mathematical algorithms developed for the detection of monoclonal immunoglobulins (MCs) in the γ- and β-regions of the electropherogram were tested on the entire material. Additional algorithms evaluating oligoclonality and polyclonal concentrations of immunoglobulins were also tested.

Results: CZE electropherograms corresponded well with HRAGE. Only one IgG MC of 1 g/L, visible on HRAGE, was not visible after CZE. Algorithms detected 94 of 95 MCs (98.9%) and 100% of those visible after CZE. Of 607 samples lacking an MC on HRAGE, only 3 were identified by the algorithms (specificity, 99%). Algorithms evaluating total gammaglobulinemia and oligoclonality also identified several cases of Bence Jones myeloma.

Conclusions: The use of capillary electrophoresis provides a modern, rapid, and cost-effective method of analyzing serum proteins. The additional option of computerized decision support, which provides rapid and standardized interpretations, should increase the clinical availability and usefulness of protein analyses in the future.
Microvolume Blood-Sampling Device with Low Hemolysis and High Consistent Yield of Serum Components
Authors: Tanaka Yoshiyuki , Noda Yuichiro , Kobayashi Mayumi , Yamada Yasuko , Hirao Konomu
Published: January 2020

Background: Blood sampling by finger puncture is convenient, but the need for centrifugation and the problem of hemolysis remain, as does instability when samples must be shipped for analysis. We aimed to develop a blood-sampling device that provided high yields of serum with limited hemolysis and enabled preservation of serum components for at least 7 days at room temperature.

Methods: For separation of blood cells, we devised a grooved, asymmetric, polysulfonate membrane impregnated with sucrose. We evaluated hemoglobin (Hb) concentrations in the serum, assay values for 15 frequently measured serum components (including glucose), and the stability of analytes in the device.

Results: In sera from the new device, the Hb concentration was ≤0.43 mg/L. Recovered serum contained 65.0% ± 4.2% (mean ± SD; n = 41) of each of the serum components obtained by centrifugation. Serum components were stable in the device for 10 days at room temperature (25 °C).

Conclusions: The newly developed device allows recovery of 60% of serum components from microvolumes of blood by finger puncture with neither degradation of analytes at room temperature nor hemolysis.
Detection of Acetylcodeine in Urine as an Indicator of Illicit Heroin Use: Method Validation and Results of a Pilot Study
Authors: Staub Christian , Marset Miguel , Mino Annie , Mangin Patrice
Published: January 2020

Background: Acetylcodeine (AC), an impurity of illicit heroin synthesis, has been suggested as an interesting biomarker of illicit heroin use.

Methods: Procedures were developed for quantification of (a) morphine, 6-monoacetylmorphine (6-AM), and codeine in urine and (b) diacetylmorphine and AC in urine. Solid-phase extraction of the analytes was performed, and the extracted analytes were analyzed by selected-ion monitoring with gas chromatography–mass spectrometry. This procedure required prior derivatization with propionic anhydride.

Results: Different validation parameters were determined, such as linearity, reproducibility, extraction recoveries, and cutoffs. Seventy-one urine specimens of illicit heroin abusers and 44 urine specimens of subjects in a heroin maintenance program were analyzed. AC was detected in 85.9% of the samples of the first group but not in any of the samples from subjects taking medical heroin. In the two groups, there were 94.4% and 84.1% 6-AM positive urine specimens, respectively. Detection times were determined for AC and codeine by parallel administration of heroin containing various percentages of AC to four voluntary patients in a heroin maintenance program. The measured detection times were 8 and 23 h for AC and codeine, respectively.

Conclusions: These results indicate that, together with detection of 6-AM in urine, AC is a suitable marker of illicit heroin use.
Compound Heterozygous Familial Hypercholesterolemia and Familial Defective Apolipoprotein B-100 Produce Exaggerated Hypercholesterolemia
Authors: Tai E Shyong , Koay Evelyn S C , Chan Edmund , Seng Tzer Jing , Loh Lih Ming , Sethi Sunil K , Tan Chee Eng
Published: January 2020

Background: Familial hypercholesterolemia (FH) and familial defective apolipoprotein B-100 (FDB) represent ligand-receptor disorders that are complementary. Individuals with both FH and FDB are unusual. We report a family with both disorders and the impact of the mutations on the phenotypes of the family members.

Methods: We used single strand conformation polymorphism (SSCP) and denaturing gradient gel electrophoresis (DGGE) for genetic analysis of all 18 exons and the promoter region of the LDL receptor and DGGE for genetic analysis of the apolipoprotein B-100 (apo B-100) gene. The functional significance of the apo B-100 mutation was studied using a U937 cell proliferation assay. Fasting serum lipid profiles were determined for the index case and seven first-degree relatives.

Results: One of the patient’s sisters had a missense mutation (Asp407→Lys) in exon 9 of the LDL receptor and a serum LDL-cholesterol concentration of 4.07 mmol/L. Four other first-degree relatives had hyperlipidemia but no LDL-receptor mutation. However, these subjects had a mutation of the apo B-100 gene (Arg3500→Trp). The cell proliferation rate of U937 cells fed with LDL from other subjects with the same mutation was fourfold less than that of controls. The index case had both FH- and FDB-related mutations. Her serum LDL-cholesterol (9.47 mmol/L) was higher than all other relatives tested.

Conclusions: Existence of both FH and FDB should be considered in families with LDL-receptor mutations in some but not all individuals with hypercholesterolemia or when some individuals in families with FH exhibit exaggerated hypercholesterolemia.
Rapid Determination of Transferrin Isoforms by Immunoaffinity Liquid Chromatography and Electrospray Mass Spectrometry
Authors: Lacey Jean M , Bergen H Robert , Magera Mark J , Naylor Stephen , O’Brien John F
Published: January 2020

Background: Congenital disorders of glycosylation (CDG) are autosomal recessive disorders that produce increased serum carbohydrate-deficient transferrin (CDT) isoforms. Methods to resolve CDT from fully glycosylated transferrin (Trf) have been based on a neutral shift in the isoelectric focusing (IEF) pattern or on a reduction in the negative charge, allowing resolution by anion-exchange chromatography. Our purpose was to develop a method of resolution and relative quantification of Trf isoforms using online immunoaffinity liquid chromatography–mass spectrometry (LC-MS).

Methods: Serum (25 μL) was diluted with 100 μL of water before application to an immunoaffinity column that sequestered Trf isoforms. Trf isoforms were eluted from the immunoaffinity column, concentrated on a C4 column, eluted from the C4 column, and introduced into the mass spectrometer. Analysis of the Trf isoforms was entirely automated and completed in <10 min per sample.

Results: The LC-MS method demonstrated that the major abnormal Trf isoforms in CDG lack one complete oligosaccharide structure (mono-oligosaccharide) or both oligosaccharide structures (a-oligosaccharide), but not the sialic acids, as presumed on the basis of IEF methods. Calculation of relative ratios among three possible species (mono-/di-oligosaccharide and a-/di-oligosaccharide) is reproducible [mean intra- and interassay CVs were 9.3% (n = 10) and 10% (n = 5), respectively]. A reference range for patients <18 years was determined by analysis of 209 samples (for mono-/di-oligosaccharide, the median was 0.041 and the range was 0.018–0.083; for a-/di-oligosaccharide, the median was 0.007 and the range was 0.002–0.036). Comparison of data obtained with an affinity chromatography-IEF method and the LC-MS method demonstrated equivalence in the interpreted results (n = 170).

Conclusions: Advantages of the LC-MS method include improved sensitivity, minimal sample preparation, and an analysis time of <10 min. The method was automated, which allowed high throughput, with >100 samples analyzed in a single day. Moreover, the nature of the oligosaccharide defect in CDG is accurately reflected by mass resolution, and subtle oligosaccharide truncations may also be detected by this method.
Plasma Protein Contents Determined by Fourier-Transform Infrared Spectrometry
Authors: Petibois Cyril , Cazorla Georges , Cassaigne André , Déléris Gérard
Published: January 2020

Background: Fourier-transform infrared (FT-IR) spectrometry has been used to measure small molecules in plasma. We wished to extend this use to measurement of plasma proteins.

Methods: We analyzed plasma proteins, glucose, lactate, and urea in 49 blood samples from 35 healthy subjects and 14 patients. For determining the concentration of each biomolecule, the method used the following steps: (a) The biomolecule was sought for which the correlation between spectral range areas of plasma FT-IR spectra and concentrations determined by comparison method was greatest. (b) The IR absorption of the biomolecule at the most characteristic spectral range was calculated by analyzing pure samples of known concentrations. (c) The plasma concentration of the biomolecule was determined using the FT-IR absorption of the pure compound and the integration value obtained for the plasma FT-IR spectra. (d) The spectral contribution of the biomolecule was subtracted from the plasma FT-IR spectra, and the resulting spectra were saved for further analyses. (e) The same method was then applied to determining the concentrations of other biomolecules by sequentially comparing the resulting FT-IR spectra.

Results: Results agreed with those obtained by clinical methods for the following biomolecules when analyzed in the following order: albumin, glucose, fibrinogen, IgG2, lactate, IgG1, α1-antitrypsin, α2-macroglobulin, transferrin, apolipoprotein (Apo)-A1, urea, Apo-B, IgM, Apo-C3, IgA, IgG4, IgG3, IgD, haptoglobin, and α1-acid glycoprotein.

Conclusion: FT-IR spectrometry is a useful tool for determining concentrations of several plasma biomolecules.
Evaluation of the TAS Analyzer and the Low-Range Heparin Management Test in Patients Undergoing Extracorporeal Membrane Oxygenation
Authors: Ambrose Theresa M , Parvin Curtis A , Mendeloff Eric , Luchtman-Jones Lori
Published: January 2020

Background: The new Low-Range Heparin Management Test (LHMT), a method for point-of-care testing (POCT) of heparinization, has been designed to function at the low to moderate heparin concentrations typically found in patients undergoing extracorporeal membrane oxygenation (ECMO). In this study, the new method is compared with two POCT methods and a laboratory-based anti-Xa assay.

Methods: We obtained 760 whole blood samples from 13 patients undergoing ECMO. All samples were tested immediately by the LHMT, the Activated Clotting Time (ACT) test, and its low-range counterpart (ACT-LR). Aliquots from the same blood draw were frozen for later anti-Xa analysis using the Diagnostica Stago method on the Roche Cobas Fara-II.

Results: The precision was best for duplicate citrated LHMT samples (CV = 3.1%). LHMT clotting times (overall median, 162 s) were typically shorter than ACT or ACT-LR times (247 and 235 s, respectively). The relationship between the LHMT and the other POCT methods differed significantly from patient to patient (P <0.0001), and a meaningful single relationship between the methods could not be obtained. The overall correlation coefficient between clotting time values and actual heparin concentrations was ≤0.48 for each of the instruments tested, although time plots of each analyzer’s data suggested that they detected heparin dosage changes within single patients.

Conclusions: The performance of the LHMT on the TAS Analyzer is equivalent to that of currently commercially available POCT methods. The lack of agreement between absolute clotting time values and heparin concentrations suggests the need for reexamination of current ECMO patient management strategy.
Hereditary Hemochromatosis Since Discovery of the HFE Gene
Authors: Lyon Elaine , Frank Elizabeth L
Published: January 2020

Background: Hereditary hemochromatosis is an inherited disorder of iron metabolism that is characterized by excessive iron deposition in major organs of the body. Chronic increased iron absorption leads to multiorgan dysfunction. Since the discovery of the gene responsible for the majority of cases, research has progressed rapidly to identify the gene product, the effects of mutations, and the implications for different populations. The protein product of the HFE gene is a transmembrane glycoprotein, termed HFE, that modulates iron uptake. Mutations in the HFE protein compromise its function and produce disease symptoms. Two mutations, C282Y and H63D, have been linked to the majority of disease cases.

Approach: We reviewed the recent literature for the molecular basis of hereditary hemochromatosis. Genotypic information was combined with biochemical and clinical phenotypic information to achieve a better understanding of the disease mechanism.

Content: This review provides a comprehensive discussion of known mutations in the HFE gene and their phenotypic expression. Diagnostic criteria using molecular genetic techniques in conjunction with traditional biochemical tests are provided. Current methods and limitations of molecular testing are examined in detail. A strategy for population screening and an algorithm for diagnosis that incorporates molecular testing are presented. Treatment by therapeutic phlebotomy and the use of blood obtained from hemochromatosis patients are discussed.

Summary: Although the disease mechanism has not been completely elucidated, phenotypic and penetrance data are becoming available. Controversy still exists concerning the role of genetic testing in diagnosis and population screening.
Infrared Analysis of Urinary Calculi by a Single Reflection Accessory and a Neural Network Interpretation Algorithm
Authors: Volmer Marcel , de Vries Jules C M , Goldschmidt Henk M J
Published: January 2020

Background: Preparation of KBr tablets, used for Fourier transform infrared (FT-IR) analysis of urinary calculus composition, is time-consuming and often hampered by pellet breakage. We developed a new FT-IR method for urinary calculus analysis. This method makes use of a Golden Gate Single Refection Diamond Attenuated Total Reflection sample holder, a computer library, and an artificial neural network (ANN) for spectral interpretation.

Methods: The library was prepared from 25 pure components and 236 binary and ternary mixtures of the 8 most commonly occurring components. The ANN was trained and validated with 248 similar mixtures and tested with 92 patient samples, respectively.

Results: The optimum ANN model yielded root mean square errors of 1.5% and 2.3% for the training and validation sets, respectively. Fourteen simple expert rules were added to correct systematic network inaccuracies. Results of 92 consecutive patient samples were compared with those of a FT-IR method with KBr tablets, based on an initial computerized library search followed by visual inspection. The bias was significantly different from zero for brushite (−0.8%) and the concomitantly occurring whewellite (−2.8%) and weddellite (3.8%), but not for ammonium hydrogen urate (−0.1%), carbonate apatite (0.5%), cystine (0.0%), struvite (0.4%), and uric acid (−0.1%). The 95% level of agreement of all results was 9%.

Conclusions: The new Golden Gate method is superior because of its smaller sample size, user-friendliness, robustness, and speed. Expert knowledge for spectral interpretation is minimized by the combination of a library search and ANN prediction, but visual inspection remains necessary.
Simultaneous Multianalyte ELISA Performed on a Microarray Platform
Authors: Wiese Rick , Belosludtsev Yuri , Powdrill Tom , Thompson Patricia , Hogan Mike
Published: January 2020

Background: A logical progression of the widely used microtiter plate ELISA is toward a protein array format that allows simultaneous detection of multiple analytes at multiple array addresses within a single well. Here we describe the construction and use of such a multiplex ELISA to measure prostate-specific antigen (PSA), α1-antichymotrypsin-bound PSA (PSA-ACT), and interleukin-6 (IL-6).

Methods: We silanized glass plates and printed the appropriate capture antibodies to allow for the construction of “sandwich” ELISA quantification assays. We examined specificity of the assay for appropriate antigen, assembled calibration curves, and obtained PSA concentrations for 14 human serum samples. We compared the serum PSA concentrations derived through the use of our array with values obtained independently using a standard ELISA method.

Results: R 2 values generated by our microarray for the PSA and PSA-ACT calibration curves were 0.989 and 0.979, respectively. Analyte concentrations used for the construction of these curves were 0.31–20 μg of protein/L of diluent. IL-6 calibration curve concentrations were 4.9–300 ng of IL-6/L of diluent. The R2 value for the IL-6 calibration curve was 0.983. The 14 human serum samples screened by this micro-ELISA technique for PSA concentrations generated a regression equation (linear) with a slope of 0.83 ± 0.10 and intercept of 0.74 ± 0.70 (R2 = 0.88).

Conclusions: Multiplexed ELISA arrays are a feasible option for analyte quantification in complex biologic samples.
Quantitative Measurement of Porphobilinogen in Urine by Stable-Isotope Dilution Liquid Chromatography-Tandem Mass Spectrometry
Authors: Ford Roddey E , Magera Mark J , Kloke Karen M , Chezick Paul A , Fauq Abdul , McConnell Joseph P
Published: January 2020

Background: Measurement of porphobilinogen (PBG) is useful in the diagnosis of the acute neurologic porphyrias. Currently used colorimetric assays lack analytical and clinical sensitivity and specificity.

Methods: We developed a liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) method for the measurement of PBG in 1 mL of urine, using 5-(aminoethyl)-4-(carboxymethyl) 1H-2,4-[13C]pyrolle-3-propanoic acid ([2,4-13C]PBG; 2.75 μg) as internal standard. After solid-phase extraction, LC-MS/MS analysis was performed in the selected-reaction monitoring (SRM) mode. PBG and [2,4-13C]PBG were monitored through their own precursor and product ion settings (m/z 227 to 210 and m/z 229 to 212, respectively). The retention time of PBG and [2,4-13C]PBG was 1.0 min in a 2.3-min analysis.

Results: Daily calibrations (n = 6) between 0.1 and 2.0 mg/L were linear and reproducible. Inter- and intraassay CVs were 3.2–3.5% and 2.6–3.1%, respectively, at mean concentrations of 0.24, 1.18, and 2.15 mg/L. The regression equation for the comparison between an anion-exchange column method (y) and the LC-MS/MS method (x) was: y = 0.84x + 0.74 (Sy|x = 5.8 mg/24 h; r = 0.85; n = 100). In 47 volunteers, PBG excretion was 0.02–0.42 mg/24 h, lower than reported reference intervals (up to 2.0 mg/24 h) based on colorimetric methods. In 85 samples with PBG ≤0.5 by LC-MS/MS, 8 (9.4%) had values ≥2.0 mg/24 h by the anion-exchange method (mean ± SD, 4.3 ± 1.8 mg/24 h). In 11 patients with confirmed diagnoses of acute porphyria and increased PBG by LC-MS/MS, 2 had values within the reported reference intervals by a quantitative anion-exchange method.

Conclusions: The quantitative LC-MS/MS method for PBG measurement exhibits greater analytical specificity and improved clinical sensitivity and specificity than currently available methods.
Multicenter Evaluation of an Artificial Neural Network to Increase the Prostate Cancer Detection Rate and Reduce Unnecessary Biopsies
Authors: Stephan Carsten , Cammann Henning , Semjonow Axel , Diamandis Eleftherios P , Wymenga Leon FA , Lein Michael , Sinha Pranav , Loening Stefan A , Jung Klaus
Published: January 2020

Background: The percentage of free prostate-specific antigen (%fPSA) has been shown to improve specificity for the diagnosis of prostate cancer (PCa) over total PSA (tPSA). A multicenter study was performed to evaluate the diagnostic value of a %fPSA-based artificial neural network (ANN) in men with tPSA concentrations between 2 and 20 μg/L for detecting patients with increased risk of a positive prostate biopsy for cancer.

Methods: We enrolled 1188 men from six different hospitals with PCa or benign prostates between 1996 and 2001. We used a newly developed ANN with input data of tPSA, %fPSA, patient age, prostate volume, and digital rectal examination (DRE) status to calculate the risk for the presence of PCa within different tPSA ranges (2–4, 4.1–10, 2–10, 10.1–20, and 2–20 μg/L) at the 90% and 95% specificity or sensitivity cutoffs, depending on the tPSA concentration. ROC analysis and cutoff calculations were used to estimate the diagnostic improvement of the ANN compared with %fPSA alone.

Results: In the low tPSA range (2–4 μg/L), the ANN detected 72% and 65% of cancers at specificities of 90% or 95%, respectively. At 4–10 μg/L tPSA, the ANN detected 90% and 95% of cancers with specificities of 62% and 41%, respectively. Use of the ANN with 2–10 μg/L tPSA enhanced the specificity of %fPSA by 20–22%, thus reducing the number of unnecessary biopsies.

Conclusions: Enhanced accuracy of PCa detection over that obtained using %fPSA alone can be achieved with a %fPSA-based ANN that also includes clinical information from DRE and prostate volume measurements.
Structure Fault Tolerance of Recursive Interconnection Networks
Authors: Sabir Eminjan , Meng Jixiang
Published: January 2020

Motivated by effects caused by structure link faults in networks, we study the following graph theoretical problem. Let $T$ be a connected subgraph of a graph $G$ except for $K_{1}$. The $T$-structure edge-connectivity $\lambda (G;T)$ (resp. $T$-substructure edge-connectivity $\lambda ^s(G;T)$) of $G$ is the minimum cardinality of a set of edge-disjoint subgraphs $\mathcal{F}=\{T_{1},T_{2},\ldots ,T_{m}\}$ (resp. $\mathcal{F}=\{T_{1}^{^{\prime}},T_{2}^{^{\prime}},\ldots ,T_{m}^{^{\prime}}\}$) such that $T_{i}$ is isomorphic to $T$ (resp. $T_{i}^{^{\prime}}$ is a connected subgraph of $T$) for every $1 \le i \le m$, and $E(\mathcal{F})$’s removal leaves the remaining graph disconnected. In this paper, we determine both $\lambda (G;T)$ and $\lambda ^{s}(G;T)$ for $(1)$ the hypercube $Q_{n}$ and $T\in \{K_{1,1},K_{1,2},K_{1,3},P_{4},Q_{1},Q_{2},Q_{3}\}$; $(2)$ the $k$-ary $n$-cube $Q^{k}_{n}$  $(k\ge 3)$ and $T\in \{K_{1,1},K_{1,2},K_{1,3},Q^{3}_{1},Q^{4}_{1}\}$; $(3)$ the balanced hypercube $BH_{n}$ and $T\in \{K_{1,1},K_{1,2},BH_{1}\}$. We also extend some known results.
Spatiotemporal Clustering and Analysis of Road Accident Hotspots by Exploiting GIS Technology and Kernel Density Estimation
Authors: Kazmi Syed Saqib Ali , Ahmed Mehreen , Mumtaz Rafia , Anwar Zahid
Published: January 2020

Traffic accidents are a common problem in any transportation network. Road traffic accidents are predicted to be the seventh leading cause of deaths by the year 2030. Recently research in the integration of geographical information systems (GIS) for analyzing accidents, road design and safety management has increased considerably. The perpetual use of GIS tools, lead this study to propose the identification of accident hotspots by exploiting GIS technology coupled with kernel density estimation (KDE). This paper proposes the use of KDE technique and GIS technology to automatically identify the accident hotspots using UK as the study area. Analysis shows that most of the accidents occur when there is a 30 mph speed limit, a weekend, in the evening time, during the months of October and November, on the single carriageway, where there is ‘T’ or staggered junction and on ‘A’ road class. Moreover, this study also proposed techniques to classify the accident severity that is classified as either fatal, serious or slight. The driver behavior and environmental features achieved an accuracy up to 85% on the severity classification with Bagging technique. Further, the shortcomings, limitations and recommendations for future work are also identified.
Prevalence, distribution, and age at clinical detection of missing permanent incisors
Authors: Beltrami Fara , Antonarakis Gregory S , Kiliaridis Stavros
Published: January 2020

Objectives

To determine the prevalence and distribution of clinically missing permanent incisors, and the age at which they are detected, in school-aged children.

Methods

A total of 2573 children aged 4–13 underwent oral health screening on at least one occasion between 2001 and 2017. In order to define a threshold age, after which permanent incisor agenesis could be suspected clinically with reasonable certainty, children who had been seen for at least three consecutive years, with any clinically missing permanent incisor were selected (n = 19). The maximum age of detection among these children was chosen as the threshold age. Based on this, a total of 766 children at or above the threshold age were screened for a cross-sectional epidemiological survey. Chi-squared tests were used to compare the prevalence of clinically missing permanent incisors among boys and girls, comparing unilateral versus bilateral, and right- versus left-sided missing teeth.

Results

Roughly 2% of the sample presented with at least one clinically missing maxillary lateral incisor. This was bilateral in half of cases. Clinically missing mandibular incisors were found in 0.5% of children. Finally, the threshold age for clinical suspicion of maxillary lateral incisor agenesis was set at 11.5 years. Agenesis was confirmed in all of the children attending a follow-up radiographic visit.

Conclusions

Approximately 1 in 50 children present with a clinically missing maxillary lateral incisor. The age at suspicion of maxillary lateral incisor agenesis can sometimes be several years after its expected eruption, perhaps due to significant variation in eruption times.
Providers’ perceptions of disrespect and abuse during childbirth: a mixed-methods study in Kenya
Authors: Afulani Patience A , Kelly Ann Marie , Buback Laura , Asunka Joseph , Kirumbi Leah , Lyndon Audrey
Published: January 2020

Disrespect and abuse during childbirth are violations of women’s human rights and an indicator of poor-quality care. Disrespect and abuse during childbirth are widespread, yet data on providers’ perspectives on the topic are limited. We examined providers’ perspectives on the frequency and drivers of disrespect and abuse during facility-based childbirth in a rural county in Kenya. We used data from a mixed-methods study in a rural county in Western Kenya with 49 maternity providers (32 clinical and 17 non-clinical) in 2016. Providers were asked structured questions on disrespect and abuse, followed by open-ended questions on why certain behaviours were exhibited (or not). Most providers reported that women were often treated with dignity and respect. However, 53% of providers reported ever observing other providers verbally abuse women and 45% reported doing so themselves. Observation of physical abuse was reported by 37% of providers while 35% reported doing so themselves. Drivers of disrespect and abuse included perceptions of women being difficult, stress and burnout, facility culture and lack of accountability, poor facility infrastructure and lack of medicines and supplies, and provider attitudes. Provider bias, training and women’s empowerment influenced how different women were treated. We conclude that disrespect and abuse are driven by difficult situations in a health system coupled with a facilitating sociocultural environment. Providers resorted to disrespect and abuse as a means of gaining compliance when they were stressed and feeling helpless. Interventions to address disrespect and abuse need to tackle the multiplicity of contributing factors. These should include empowering providers to deal with difficult situations, develop positive coping mechanisms for stress and address their biases. We also need to change the culture in facilities and strengthen the health systems to address the system-level stressors.
Does improving appropriate use of malaria medicines change population beliefs in testing and treatment? Evidence from a randomized controlled trial
Authors: Maffioli Elisa M , Mohanan Manoj , Saran Indrani , O’Meara Wendy Prudhomme
Published: January 2020

A major puzzle in malaria treatment remains the dual problem of underuse and overuse of malaria medications, which deplete scarce public resources used for subsidies and lead to drug resistance. One explanation is that health behaviour, especially in the context of incomplete information, could be driven by beliefs, pivotal to the success of health interventions. The objective of this study is to investigate how population beliefs change in response to an experimental intervention which was shown to improve access to rapid diagnostic testing (RDT) through community health workers (CHWs) and to increase appropriate use of anti-malaria medications. By collecting data on individuals’ beliefs on malaria testing and treatment 12 and 18 months after the experimental intervention started, we find that the intervention increases the belief that a negative test result is correct, and the belief that the first-line anti-malaria drugs (artemisinin-based combination therapies or ACTs) are effective. Using mediation analysis, we also explore some possible mechanisms through which the changes happen. We find that the experience and knowledge about RDT and experience with CHWs explain 62.4% of the relationship between the intervention and the belief that a negative test result is correct. Similarly, the targeted use of ACTs and taking the correct dose—in addition to experience with RDT—explain 96.8% of the relationship between the intervention and the belief that the ACT taken is effective. As beliefs are important determinants of economic behaviour and might guide individuals’ future decisions, understanding how they change after a health intervention has important implications for long-term changes in population behaviour.
P062 A SYSTEMATIC REVIEW ON POWER ESTIMATION TO SUPPORT SAMPLE SIZE CALCULATION FOR RANDOMISED TRIALS IN INFLAMMATORY BOWEL DISEASE
Authors: Lakunina Svetlana , Iheozor-Ejiofor Zipporah , Gordon Morris , Akintelure Daniel , Sinopoulou Vassiliki
Published: January 2020

Inflammatory bowel disease is a collection of disorders of the gastrointestinal tract, characterised by relapsing and remitting inflammation. Studies have reported several pharmacological or non-pharmacological interventions being effective in the management of the disease. Sample size estimation with power calculation is necessary for a trial to detect the effect of an intervention. This project critically evaluates the sample size estimation and power calculation reported by randomised controlled studies of inflammatory bowel disease management to effectively conclude appropriateness of the studies results.

We conducted a literature search in the Cochrane database to identify systematic literature reviews. Their reference lists were screened, and studies were selected if they met the inclusion criteria. The data was extracted based on power calculation parameters and outcomes, results were analysed and summarised in percentages, means and graphs.

We screened almost all trials about the management of inflammatory bowel disease published in the past 25 years. 232 studies were analysed, of which 167 reported power calculation. Less than half (48%) of these studies achieved their target sample size, needed for them to accurately conclude that the interventions were effective. Moreover, the average minimal difference those studies were aimed to detect was 30%, which could be not enough to prove the effect of an intervention.

To conclude inaccurate power calculations and failure to achieve the target sample sizes can lead to errors in the results on how effective an intervention is in the management of inflammatory bowel disease.