bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laboratory Investigation of Cerebrospinal Fluid Proteins
Authors: Thompson E J , Keir G 
Published: February 2014

Analysis of CSF proteins is useful in the diagnosis and management of neurological diseases in the following situations: In inflammatory conditions when there is breakdown of blood-CSF barrier integrity. Meningitis is a medical emergency, with CSF total protein measurement being only a screening test. In the detection of immune responses within the CNS. This is by far the most important application in a routine clinical setting, as it is now a firmly established criterion in the diagnosis of multiple sclerosis. Oligoclonal bands restricted to the CSF are the only reliable indicators of intrathecal immunoglobulin G synthesis and are practically always associated with inflammatory disease of the CNS. The method of choice for detecting oligoclonal bands is isoelectric focusing with immunofixation. Quantitative measurement of IgG in the CSF is of no value in diagnostic pathology. In destructive brain diseases when brain-specific proteins are released into the CSF, measurement of these proteins can give prognostic information.
The Role of Magnesium in Clinical Biochemistry: An Overview
Authors: Ryan Michael F 
Published: February 2014

Magnesium is the second most abundant intracellular cation. It is essential for a wide variety of metabolically important reactions, in particular those involving ATP. Hypomagnesaemia is surprisingly common in hospital populations but is sometimes either undetected or overlooked. Serum magnesium concentrations provide a guide to magnesium status but while hypomagnesaemia is a reliable indicator of magnesium deficiency, normomagnesaemia does not exclude magnesium depletion. A wide variety of conditions predispose to magnesium depiction. Clinical magnesium deficiency has potentially fatal consequences in vulnerable groups of patients and should be excluded in all such cases. Magnesium deficiency may result in hypokalemia, hypocalcaemia or other disturbances of electrolyte homeostasis, refractory cardiac arrhythmias, or increased sensitivity to digoxin. The capacity to measure serum and urine magnesium concentrations rapidly, regularly and reliably should be part of the repertoire of all clinical chemistry laboratories involved in the care of critically ill patients.
The Effect of Weight Correction on Risk Calculations for Down's Syndrome Screening
Authors: Reynolds T M , Penney M D , Hughes H , John R 
Published: February 2014

Recent advances in prenatal screening have led to the possibility that the risk of Down's syndrome associated pregnancy may be assessed by blood tests for maternal serum alphafetoprotein, human chorionic gonadotrophin (and possibly unconjugated oestriol) taken at 15–18 weeks of gestation. In neural tube defect screening correction of maternal serum alphafetoprotein for maternal weight has been recommended, although the precise method for weight correction is still under debate. We report an assessment of weight correction for maternal serum alphafetoprotein and human chorionic gonadotrophin based on 1408 singleton pregnancies and for unconjugated oestriol based on 197 singleton pregnancies. We demonstrate that weight correction of maternal serum alphafetoprotein and human chorionic gonadotrophin is statistically valid but that correction of unconjugated oestriol is not.
Triglyceride Fatty Acid Chain Length Influences the Post Prandial Rise in Serum Intestinal Alkaline Phosphatase Activity
Authors: Day A P , Feher M D , Chopra R , Mayne P D 
Published: February 2014

Intestinal alkaline phosphatase (IALP) activity rises following the ingestion of a fat-containing meal. Previous studies on intestinal fluid and lymph have shown that the magnitude of this response is dependent upon fatty acid chain length. To examine this relation in the serum of healthy humans, 10 subjects consumed two standardized fat meals. One meal contained predominantly long chain fatty acid triglycerides, the other contained predominantly medium chain fatty acid triglycerides. Serum IALP activity was measured in serial blood samples using a sensitive immunological assay. IALP activity was ABO blood group and secretor status dependent. The post-prandial rise in serum IALP activity was significantly greater following the long chain fatty acid meal than following the medium chain fatty acid meal. Previous observations of the fatty acid chain length dependency of the IALP response to fat ingestion, therefore, also apply in the serum of healthy humans under normal physiological conditions. Standardized fat meals provide the basis of a useful method for the investigation of the role of IALP in fat absorption.
Free Beta Human Choriogonadotropin in Down's Syndrome Screening: A Multicentre Study of its Role Compared with other Biochemical Markers
Authors: Spencer Kevin , Coombes Ed J , Mallard Angela S , Ward A Milford 
Published: February 2014

To ascertain the value of maternal serum free β-human choriogonadotropin subunit measurement in Down's syndrome screening and to compare its effectiveness when screening with a variety of biochemical markers, we have evaluated maternal serum free β-human choriogonadotropin, total human choriogonadotropin, α-fetoprotein and unconjugated oestriol in a large multicentre study of over 2800 unaffected cases and 90 affected cases, the largest collection of Down's cases ever reported. Of all the markers identified to date, free β-human choriogonadotropin is the marker of choice for use in Down's syndrome screening. When used in early gestation (14–16 weeks) in combination with α-fetoprotein and maternal age, it will allow the detection of 77% of Down's cases. A side-by-side comparison with the performance of total human choriogonadotropin shows the superior detection efficiency of free β-human choriogonadotropin. Unconjugated oestriol adds nothing further to the detection rate compared with the use of α-fetoprotein and free β-human choriogonadotropin alone, and its use results in a 1% increase in false positive rate. We conclude that unconjugated oestriol has no value in Down's screening. The superior detection rate obtained using free β-human choriogonadotropin is a result of superior detection of Down's cases in women under 30 years old, where the free β-human choriogonadotropin combination detects 100% more cases than does the total human choriogonadotropin combination.
Audit of Automated Requesting of Serum Magnesium Measurement in Patients with Hypocalcaemia
Authors: Masters P W 
Published: February 2014

Laboratory computer records for 71 consecutive hypocalcaemic patients (albumin-adjusted calcium < 2 · 00 mmol/L) without chronic renal failure revealed that 50 (70%) did not have serum magnesium measured. A second review of computer records was carried out 6 months after the initiation of an automated requesting program. This identified 14 patients with hypomagnesaemia (serum magnesium < 0·70 mmol/L) who may otherwise have been undiagnosed. The direct cost to the laboratory was an additional 19 magnesium analyses per month. It is concluded that hypomagnesaemia is commonly associated with hypocalcaemia but is under-diagnosed. Automated requesting of serum magnesium measurement is a cost-effective way of identifying these patients. However, the fact that only half of these patients had follow-up magnesium requests suggests that there may be a need for further education of clinicians in the significance of hypomagnesaemia.
A Survey of Diagnoses in Patients with a Low Intact Parathyroid Hormone Concentration
Authors: Manning E M C , Fraser W D 
Published: February 2014

Intact parathyroid hormone (PTH) was analysed in 1107 samples over a 13 month period. Of these, 181 samples (16%) gave results of ≤ 1 pmol/L and the case notes of 169 of these 181 patients were examined. Eighty-two patients (48%) were hypercalcaemic at the time of the PTH assay. As expected, the most common diagnosis in this group was hypercalcaemia of malignancy but surprisingly this accounted for only 42 of the hypercalcaemic patients; an unexpectedly high proportion (20 patients) had chronic renal failure with hypercalcaemia due to excessive treatment with 1α-hydroxycholecalciferol; eight patients had transient unexplained hypercalcaemia and the remaining 12 patients were hypercalcaemic for a variety of causes including immobilization, bendrofluazide treatment and Paget's disease. Fifty-nine patients (35%) were normocalcaemic: 26 had osteoporosis, 10 had chronic renal failure and the remainder had a wide range of diagnoses. It is possible that the low intact PTH result in a proportion of the normocalcaemic group was caused by ingestion of calcium tablets prior to blood sampling for PTH. Twenty-eight patients (17%) were hypocalcaemic: 24 of these had hypoparathyroidism, two had chronic renal failure and two had transient unexplained hypocalcaemia.
Early Diagnosis of Acute Myocardial Infarction: CK-MB and Myoglobin Compared
Authors: Kilpatrick W S , Wosornu D , McGuinness J B , Glen A C A 
Published: February 2014

We have measured changes in plasma concentration of creatine kinase MB (CK-MB) and myoglobin in 50 patients admitted to the Coronary Care Unit with chest pain of presumed cardiac origin. Eight serial blood samples were obtained in the 6 h period following admission and both CK-MB and myoglobin concentrations were measured. We compared the performance of single values of both tests. Myoglobin concentration, in the coronary care population studied, proved to be as specific as CK-MB concentration (92–6% in both cases) but with sensitivity of 100% being achieved 1 · 5 h post admission rather than 4 h post admission in the case of CK-MB. On this evidence, measurement of plasma myoglobin could prove useful in the rapid diagnosis of myocardial infarction with consequent effects on optimal Coronary Care utilisation and selection of patients for thrombolytic therapy.
Expression of Gonadotropin-Releasing Hormone Receptor in Human Epithelial Ovarian Carcinoma
Authors: Imai Atsushi , Ohno Tsukasa , Ohsuye Kazuhiro , Tamaya Teruhiko 
Published: February 2014

We have previously demonstrated the presence of gonadotropin-releasing hormone (Gn-RH) messenger ribonucleic acid (mRNA) in epithelial ovarian carcinoma. In this study, the expression of Gn-RH receptor (Gn-RHR) was investigated in human ovarian carcinoma and human ovarian carcinoma cell line. Gn-RHR was determined by [3H] Gn-RH binding assay. Gn-RHR mRNA was determined by reverse transcription-polymerase chain reaction using oligonucleotide primers synthesized based on published human Gn-RHR sequence. Specific Gn-RH binding sites were shown to be present in plasma membrane isolated from five ovarian mucinous cystadenocarcinoma samples and one serous cystadenocarcinoma ( Kd = 15·3 ± 8·08 nmol/L). Gn-RHR mRNA was detected in four mucinous cystadenocarcinoma specimens, one serous cystadenocarcinoma, and SK-OV-3 cells, but not in white blood cells. These results suggest that Gn-RH may play an autocrine regulatory role in the growth of ovarian carcinoma.
Determination of Total and Herpes Simplex Virus Specific Monomeric and Dimeric IgA in Serum and Cerebrospinal Fluid by Ultracentrifugation
Authors: Öhman Sten , Ernerudh Jan , Roberg Magnus , Forsberg Pia 
Published: February 2014

An improved method is described for differentiating between monomeric and dimeric total and herpes simplex virus (HSV) specific IgA by ultracentrifugation in sucrose gradient, using recovery and quantitative analysis of the fractions obtained. Calculation of monomeric and dimeric IgA was based on IgG as an internal standard. Intrathecally produced monomeric and dimeric IgA were judged by calculating IgA indices for each form. A new type of formula indicating relative over-production of dimeric compared with monomeric IgA (IgA dimeric-monomeric index) is suggested. The method was applied to serum and cerebrospinal fluid (CSF) from three patients with HSV encephalitis. The index for monomeric as well as dimeric IgA was high during the acute phase of the disease, indicating intrathecal synthesis of both molecular forms. One year after onset, there was no detectable HSV-specific IgA in CSF: Both molecular forms, however, remained in serum. The amount of dimeric compared with monomeric IgA was high during the acute phase, and subsequently decreased after successful treatment. A new finding was the detection of HSV-specific IgA heavier than dimeric IgA in serum one year after onset of the disease. These components may be tetrameric IgA, or immune complexes containing IgA.
A Comparative Study of Six Commercial Lipoprotein(a) Assays in Seventeen Laboratories within the British Isles
Authors: Mackness Michael I , Bhatnagar Deepak , Weiringa Gilbert , MBewu Anthony , Haynes Barbara , Durrington Paul N 
Published: February 2014

Seventeen laboratories in the British Isles participated in a study to compare six different commercially available immunoassays for serum lipoprotein(a) (Lp(a)) and to establish reasons for the variations in the measurement of serum Lp(a) concentrations. Pooled serum was distributed neat and after dilution at a central laboratory. In addition, the central laboratory sent unpooled serum sampled monthly from six healthy volunteers to each of the participating laboratories for 12 months. The assays all gave linear dilution curves which were parallel, although the reported values varied twofold. There were major differences in the values assigned to different manufacturers' calibrants which was not explained by whether the units employed were whole Lp(a), the protein moiety of Lp(a) or simply apolipoprotein(a). The coefficient of variation for the reported value of Lp(a) over 12 months was 33%. The component variation was 10% after adjustment for inter-laboratory and intra-laboratory variation. Some individuals clearly had a greater tendency to variable serum Lp(a) concentrations than others, but all the assays responded to this in the same way. Thus, the assays tested probably measured the same analyte. The problem of calibration could largely be addressed if agreement were reached by the manufacturers. Even with improvements in analytical precision it should be realized that multiple measurements of serum Lp(a) levels are necessary if the true mean value is to be appreciated. Individuals showing wide variation in serum Lp(a) may reward further study if its role is to be established.
Cardiac Troponin T Release into Plasma after Acute Myocardial Infarction: Only Fractional Recovery Compared with Enzymes
Authors: Kragten Johannes A , Hermens Wim Th , van Dieijen-Visser Marja P 
Published: February 2014

After acute myocardial infarction (AMI) cardiac enzymes and proteins are released into plasma and are used as biochemical markers of cardiac muscle injury. We studied the completeness of the release of troponin T, a cardiac protein that is largely bound to myofibrillar structures and compared it with the release of cytoplasmic cardiac enzymes in 22 patients with AMI, who were treated with thrombolytic therapy. Creatine kinase (CK; EC 2.7.3.2), hydroxybutyrate dehydrogenase (HBDH), lactate dehydrogenase (LDH; EC 1.1.1.27) and troponin T were assayed serially in plasma samples obtained frequently and for at least 168 h after the start of thrombolytic therapy. Cumulative release of enzymes and troponin T in plasma were calculated by using a two-compartment model for circulating proteins. In order to express the cumulative plasma releases in gram equivalents (g-eq) healthy myocardium per litre plasma (infarct size), we determined HBDH, LDH and total troponin T contents per gram net weight of tissue in 17 human hearts obtained post-mortem from patients who died from non-cardiac causes. Mean (SD) tissue contents per gram wet weight of, respectively, 156 ± 25 U/g, 385 ± 59 U/g and 234 ± 65 μg/g were found. For the cardiac enzymes CK, HBDH and LDH the mean (SEM, n = 22) total release over 72 h, was, respectively, 5·9 ± 1·5, 5·9 ± 1·6 and 6·1 ± 1·7 g-eq/L. There was no further increase after 72 h and the differences between enzymes were not significant. The mean (SEM) cumulative troponin T release, expressed in gram equivalents of myocardium per litre of plasma was only 0·30 ± 0·09 g-eq/L after 72 h and 0·51 ± 0·61 g-eq/L after 168 h. After 72 h total recovery of troponin T in g-eq/L was only 5% and after 168 h only 8·5% of the total recovery of cytoplasmic cardiac enzymes after 72 h. Cumulative troponin T release after 72 h and after 168 h correlates well with infarct size, estimated from cumulative cytoplasmic enzyme release. However, quantification of infarct size should preferably be performed from plasma release curves of cytoplasmic cardiac enzymes or proteins in order to prevent underestimation of infarct size, caused by incomplete release of the non-cytoplasmic proteins.
β-Hexosaminidase Isoenzymes A and B in Middle-Aged and Elderly Subjects: Determinants of Plasma Levels and Relation to Vascular Disease
Authors: Hultberg B , Isaksson A , Lindgren A , Israelsson B , Brattström L 
Published: February 2014

Plasma/serum β-hexosaminidase (Hex) activity is known to be increased in chronic alcoholism, liver disorders, pregnancy and diabetes mellitus. Hex activity also shows an association with risk factors for vascular disease and heredity for arteriosclerosis. There are several isoenzymes of Hex. Using an enzyme immunoassay for Hex isoenzymes (Hex A and Hex B) we studied possible determinants of Hex isoenzymes and their relation to vascular disease in randomly invited ( n = 244) 35–95-year-old men and women. In both sexes there were significant age-related increases in Hex activities and men exhibited higher activity of both isoenzymes. Both Hex isoenzymes correlated with age, systolic blood pressure, serum triglycerides and liver enzymes, whereas Hex A was distinguished from Hex B by its stronger correlation with blood glucose. In multiple linear regression analysis Hex A was explained to 20·7% by blood glucose, age, serum aspartate aminotransferase and glutamyl transpeptidase. Hex B was explained to 14% by age, serum glutamyl transpeptidase and serum triglycerides. There was no significant increase in Hex isoenzymes in subjects with hypertension, diabetes mellitus or myocardial disease, nor did current smokers exhibit any increase of these enzymes compared to non-smokers. The main conclusion is that liver function, as reflected by the level of liver enzymes and glucose metabolism, is the major determinant for Hex isoenzymes in plasma.
Sex Steroids Regulate the Expression of Plasminogen Activator Inhibitor-1 and its mRNA in Fibroblasts Derived from Uterine Endometrium
Authors: Fujimoto Jiro , Hori Masashi , Ichigo Satoshi , Tamaya Teruhiko 
Published: February 2014

In order to clarify a role of stromal cells in sex steroidal neovascularization, plasminogen activator inhibitor (PAI)-1 [an inhibitor of tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA)] and its messenger ribonucleic acid (mRNA) were analysed in fibroblasts derived from uterine endometrium as a model for endometrial stromal cells under the influence of sex steroids. The determinations were carried out by an enzyme-linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction-Southern blotting, respectively. In the fibroblasts, either estradiol or progestogens (progesterone, medroxy progesterone acetate or 17α-hydroxyprogesterone) induced expressions of PAI-1 and its mRNA, and their combination further increased their expression by approximately twofold. PAI-1 from endometrial stromal cells under the influence of sex steroids might contribute to endometrial neovascularization through its effect on endothelial cells in endometrial vessels.
Comparison of the Bio-Rad Porphyrin Column Test with a Simple Spectrophotometric Test for Total Urine Porphyrin Concentration
Authors: Zuijderhoudt F M J , Bok J Dorresteijn-de 
Published: February 2014

We compared two screening methods for increased urine porphyrin concentration and compared the results with a high-performance liquid chromatography (HPLC) method. The screening methods were the Bio-Rad (Porphyrin) Column Test and a simple spectrophotometric method. Results were obtained for urines with three different porphyrin patterns. Both screening methods were easy to perform. The accuracy and precision of the spectrophotometric method were both slightly better than that of the Bio-Rad Column Test. Recovery measurements in samples with different porphyrin patterns varied between 73% and 59% ( n = 12) for the spectrophotometric method and between 82% and 116% ( n = 12) for the Bio-Rad Column Test as compared to HPLC. Between batch precision measurements revealed coefficients of variation for spectrophotometric and Bio-Rad methods for 2%–4% and 4%–10%, respectively. The recovery of the porphyrins illustrates the Bio-Rad Column Test to be more susceptible to variation in urine porphyrin composition. Both methods will show satisfactory results in cases of overt porphyria because of the high urine porphyrin concentration.
Evaluation of Five Different High-Density Lipoprotein Cholesterol Assays: The Most Precise are Not the Most Accurate
Authors: de Keijzer Marinus H , Elbers Dion , Baadenhuijsen Henk , Demacker Pierre N M 
Published: February 2014

We evaluated the accuracy and performance of four different test kits for the direct determination of high-density lipoprotein (HDL)-cholesterol and compared them with the phosphotungstic acid/MgCl2 assay. All four homogeneous assays were precise (within-run CV of <2·0% and between-run CV of <6·4%); both assays based on immuno-inhibition had the lowest CVs (within-run 1·3% and 0·9%; between-run 2·3% and 2·2%). Interference from haemolysis was negligible, but triglyceride concentrations gave a negative interference. The effects of conjugated and unconjugated bilirubin were opposite: conjugated bilirubin showed a negative interference of up to 40%; unconjugated bilirubin interfered positively up to 50%. Using the recently validated indirect phosphotungstic acid/MgCl2 method as a comparison, all four homogeneous assays did not fulfil the National Cholesterol Education Program total error standard, mainly due to the positive biases of 12 to 42%, apparently associated with improper calibrators. Both assays involving immuno-inhibition showed a concentration-dependent bias.