Lidar quantification of bank erosion in Blue Earth County, Minnesota.

Sediment and phosphorus (P) transport from the Minnesota River Basin to Lake Pepin on the upper Mississippi River has garnered much attention in recent years. However, there is lack of data on the extent of sediment and P contributions from riverbanks vis-à-vis uplands and ravines. Using two light detection and ranging (lidar) data sets taken in 2005 and 2009, a study was undertaken to quantify sediment and associated P losses from riverbanks in Blue Earth County, Minnesota. Volume change in river valleys as a result of bank erosion amounted to 1.71 million m over 4 yr. Volume change closely followed the trend: the Blue Earth River > the Minnesota River at the county's northern edge > the Le Sueur River > the Maple River > the Watonwan River > the Big Cobb River > Perch Creek > Little Cobb River. Using fine sediment content (silt + clay) and bulk density of 37 bank samples representing three parent materials, we estimate bank erosion contributions of 48 to 79% of the measured total suspended solids at the mouth of the Blue Earth and the Le Sueur rivers. Corresponding soluble P and total P contributions ranged from 0.13 to 0.20% and 40 to 49%, respectively. Although tall banks (>3 m high) accounted for 33% of the total length and 63% of the total area, they accounted for 75% of the volume change in river valleys. We conclude that multitemporal lidar data sets are useful in estimating bank erosion and associated P contributions over large scales, and for riverbanks that are not readily accessible for conventional surveying equipment.

Multicentre evaluation of the diagnostic value of cardiac troponin T, CK-MB mass, and myoglobin for assessing patients with suspected acute coronary syndromes in routine clinical practice.

OBJECTIVE: To assess the diagnostic efficiency of the third generation cardiac troponin T assay in routine clinical practice. DESIGN: Prospective observational study of unselected consecutive admissions. SETTING: Multicentre study in 43 teaching and non-teaching hospitals in 13 countries. SUBJECTS: 1105 hospital admissions, median age 67 years (range 15-96 years, 63.7% male) with suspected acute coronary syndromes (72.3% of cases) or other non-specific symptoms where cardiac disease required exclusion (27.7%). INTERVENTIONS: Over the study period, myoglobin, creatine kinase MB isoenzyme (CK-MB), and cardiac troponin T where measured in parallel with conventional diagnostic tests. Final diagnostic classification involved standard ECG changes and CK-MB mass exceeding 5.0 microg/l. MAIN OUTCOME MEASURES: Diagnostic efficiency was assessed by receiver operator characteristic curve analysis including and excluding patients with unstable angina. RESULTS: Measurement of cardiac troponin T was diagnostically equivalent to CK-MB and both were better than myoglobin, with areas under the curve at 12 hours of 0.94, 0.99, and 0.80, respectively. Diagnostic criteria using CK-MB were inadequate and showed bias when patients with unstable angina were included. Elevations of cardiac troponin T did not occur when cardiac disease could be categorically excluded but were found in clinical conditions other than suspected acute coronary syndromes. CONCLUSIONS: CK-MB is unsuitable as a diagnostic gold standard even at the proposed lower threshold. A lower cut off for cardiac troponin T of 0.05 microg/l should be used for diagnosis of acute myocardial infarction. Diagnosis of acute myocardial infarction cannot be made solely on the basis of a cardiac troponin T result.

A multicentre evaluation of tumour marker determinations using the automatic Enzymun-Test Systems ES 300 and ES 600/700.

A multicentre evaluation of the determination of carcinoembryonic antigen (CEA), the cancer antigens CA 15-3, CA 19-9, CA 72-4 and CA 125 (II generation), the cytokeratin 19 marker Cyfra 21-1 and alpha-foetoprotein (AFP) using the Enzymun-Test System (ES 300 and ES 600/700) was performed in 23 laboratories. The tumour markers were measured in a total of 4266 human serum samples. The intra-assay precision was less than 5% in 80% of all serum samples investigated and in 95% of the serum samples at or above the cut-off level of the tumour markers. Inter-assay precision was less than 10% in 86% of the marker determinations. The interlaboratory survey also showed high reproducibility for the determination of all the tumour markers. In 3 laboratories the results of CA 15-3 in 283 serum samples were compared with the IRMA method of CIS bio international. The regression coefficient, r, was 0.967. In 4 laboratories the results of CEA in 312 samples were compared with the results obtained on the IMx analyser. The regression coefficient, r, was 0.967. In benign gynaecological diseases, CA 125 (II) was most frequently elevated in endometriosis. In gastrointestinal diseases it was proven that CEA is still the marker with the highest sensitivity as compared with CA 19-9 and CA 72-2 (59% with healthy controls as the reference group and 44% with patients having benign gastrointestinal disease as the control group). In pancreatic cancer CA 19-9 showed the highest sensitivity (78% and 62% respectively). In gastric cancer the three markers did not show statistically different results. When the gastric cancer patients were divided according to stage, CA 72-4 appeared to be more sensitive than CA 19-9 only in stage IV.

Multicentre evaluation of a new fully automated enzyme immunoassay for total prostate-specific antigen.

UNLABELLED: The evaluation is reported of a newly developed automated assay for measuring total prostate-specific antigen: Enzymun-Test PSA. Starting with a small field study, the study was extended to 74 laboratories in different countries. The median values for the intra-assay imprecision ranged from 5.0% (0.0-2.0 micrograms/l) to 2.5% (> 10.0 micrograms/l). For the inter-assay imprecision the results for the same ranges were 23.2 and 3.8%, respectively. The lower limit of detection, biological and functional sensitivity were 0.03, 0.1 and 0.25 micrograms/l, respectively. The linearity and dilution experiments showed acceptable data. The determined reference ranges (95% confidence intervals) were: men < 40 years: 0.1-1.3 micrograms/l, men 40-50 years: 0.2-2.0 micrograms/l, men 50-60 years: 0.2-3.0 and men > 60 years: 0.2-4.5 micrograms/l. Comparison of Enzymun-Test PSA with most present-day commercially available assays generally revealed very good correlations. IN CONCLUSION: the new Boehringer Mannheim Enzymun-Test PSA is compatible with the state-of-the-art for the measurement of total prostate-specific antigen.

Molecular analysis of the 3,6-dideoxyhexose pathway genes of Yersinia pseudotuberculosis serogroup IIA.

Salmonella enterica and Yersinia pseudotuberculosis are the only examples in nature known to use a variety of 3,6-dideoxyhexose derivatives as O antigen constituents. To allow a comparison of the responsible biosynthetic genes of the two organisms, we have sequenced a section of the Y. pseudotuberculosis serogroup IIA rfb region that contained the genes for the abequose biosynthetic pathway. Comparison of the identified genes with the rfb region of S. enterica LT2 showed that the two dideoxyhexose pathway gene clusters are related. The arrangement of the genes was largely conserved, and the G + C compositions of the two DNA regions were strikingly similar; however, the degree of conservation of nucleotide and protein sequences suggested that the two gene clusters have been evolving independently for considerable time. Hybridization experiments showed that the dideoxyhexose pathway genes are widespread throughout the various serogroups of Y. pseudotuberculosis.

Anomalous tumour marker concentrations in renal transplant patients.

Serial serum determinations of the tumour associated antigens carcinoembryonic antigen, tissue polypeptide antigen, CA 19-9, CA 15-3 and CA 125 were performed on 70 patients who were undergoing, or had undergone renal transplantation. The period of observation ranged from 4 days pre-operative to 708 days post-operative, although daily monitoring was usually carried out during the first 14-35 days post-operatively. With the exception of tissue polypeptide antigen, which was analysed with an immunoluminometric assay, all analytes were measured with the Enzymun-Test System ES-300 using immunoenzymometric assays with colorimetric determination. The interassay coefficients of variation were less than 5% for the immunoenzymometric assays and 8.7% for tissue polypeptide antigen, all values being derived from 20 consecutive assays. Only 8/70 patients with no complications showed normal concentrations for all five analytes. 6/79 patients showed parallel changes of at least three markers. 7/70 patients had transient elevations of at least one marker, whereas 25/70 patients had a continual elevation of CA 125, 9/70 CA 19-9 and 1/70 CA 15-3, although no patient showed evidence of disease. Two patients, each with 2 rejection episodes, showed daily fluctuations up to 100% for all markers, with the exception of carcinoembryonic antigen. There was no correlation between elevated tumour markers and cytomegalovirus infection.

Multicenter technical and clinical evaluation of a fully automated enzyme immunoassay for CA 125.

The technical performance and clinical usefulness of the newly developed Enzymun-Test CA 125 (Boehringer Mannheim) was evaluated in a multicenter study. Sera tested were obtained from healthy control subjects (n = 1003) and from patients with benign conditions (379), ovarian cancer (518), or other malignancies (479). Intra- and interassay variability was low at CA 125 concentrations greater than 100 units/mL. Intra- and interassay CVs were respectively less than or equal to 36% and 23% for the low CA 125 concentrations (less than or equal to 35 units/mL) and less than or equal to 15% and 14% for the medium CA 125 concentrations (36- less than or equal to 100 units/mL). Interlaboratory reproducibility of the Enzymun-Test CA 125 was excellent. A strong linear correlation was observed between Enzymun-Test CA 125 and three of four other commercially available assays of CA 125 in serum. Cutoff values of 35 units/mL in three of these other tests corresponded to Enzymun-Test CA 125 values ranging from 27.0 to 42.1 units/mL. In the fourth test, an enzyme immunoassay, a cutoff of 35 units/mL corresponded to Enzymun-Test values ranging from 64.1 to 77.0 units/mL. Discordant, as yet unexplained, results in which Enzymun-Test values were greater than 65 units/mL and Centocor CA 125 immunoradiometric assay results were less than 35 units/mL were found in 15 of 1003 samples (1.5%) of apparently healthy control subjects. Sensitivity and performance of the Enzymun-Test were very similar to those of the Centocor assay for sera from the patients with various benign disorders or malignant diseases. Given its excellent automated technical performance, this new CA 125 serum assay is feasible for monitoring ovarian cancer patients. Test results are interchangeable with those from other laboratories and, in general, with those obtained by most other CA 125 tests.

Molecular cloning and genetic characterization of the rfb region from Yersinia pseudotuberculosis serogroup IIA, which determines the formation of the 3,6-dideoxyhexose abequose.

The rfb region of Yersinia pseudotuberculosis serogroup IIA has been cloned and expression of O antigen in Escherichia coli K12 was demonstrated. Transposon mutagenesis analysis confined the DNA region required for O antigen expression to a 19.3 kb fragment, and the O antigen expressed was visualized by SDS-PAGE and silver staining. Southern hybridization analysis demonstrated significant levels of similarity between the Yersinia rfb region and the 3,6-dideoxyhexose pathway genes rfbF and rfbG, previously isolated from Salmonella enterica LT2, but no similarity to the abequose synthase gene rfbJ of the same strain or the paratose synthase gene rfbS isolated from S. enterica Ty2. The evolutionary relationship between the abequose biosynthetic genes of the two species of Salmonella and Yersinia is discussed.

Multicenter evaluation of new enzyme-linked immunoassays of follitropin and lutropin in serum or plasma.

Results from a multicenter evaluation of two new enzyme-linked immunosorbent assays [Enzymun-Test for follitropin (FSH) and lutropin (LH)] are presented and compared with results from 11 other commercial immunoassays, radioactive as well as nonradioactive. Enzymun-Test FSH and LH assays are suitable for automated systems and manual applications. The tests were reproducible (CV less than 5%), highly specific, and sensitive enough (less than 0.5 int. unit/L) to measure the hormones directly in almost all patients' samples, except for LH measurements in prepubertal children. We did not find interference by heterophilic antibodies or other factors. A comparison of assays for FSH found very good agreement among all modern two-site assays; competitive immunoassays almost invariably yielded systematically lower results for FSH, probably because of the heterogeneity of the International Reference Preparation (2nd IRP FSH, 78/549). For LH also we found good agreement, with no systematic differences among the various reagents. Guidelines for reference values with the new reagents are given.

One-step sandwich enzyme immunoassay for insulin using monoclonal antibodies.

An enzyme-linked immunosorbent assay for the measurement of insulin in human serum has been developed. The test is based on the sandwich technique with two monoclonal antibodies directed against two different epitopes of insulin using coated plastic tubes as the solid phase and horse radish peroxidase as the label. The immunoreactions are completed in one step within 2 h. The horse radish peroxidase activity bound to the tube wall is measured photometrically after an additional 1-h incubation with the substrate. The standards used cover the range from 0 to 260 mU insulin/L. Employing the Enzymun-Test System ES 22 modular batch analyzer, the detection limit was found to be 3.7 mU insulin/L. Coefficients of variation (CV's) between 1.4-7.8% for intraassay precision and 5.6-10% for interassay precision were obtained over the concentration range of 17-107 mU Insulin/L. The correlation between the procedure described here (y) and a commercially available double antibody radioimmunoassay (x) is expressed by the following equation: y = 1.07x + 1.14 mU insulin/L.

Multicentre study of a new test for TSH-screening in blood spots.

A multicentre study for the detection of congenital hypothyroidism by enzyme-immunoassay of thyrotropin in filter paper blood spots is described. The method is accurate, with good precision and adequate sensitivity. No interference due to common blood constituents has been observed. Moreover, the TSH determination can easily be performed by photometric measurement of enzyme activity. Large series of samples can be processed by automation using common laboratory analysers. Values show good agreement with those obtained by RIA methods. We present a method for screening for congenital hypothyroidism which can be performed in all clinical laboratories.

Serum TSH measurements by a sensitive enzyme immunoassay discriminate euthyroid from hyperthyroid subjects and avoid the need for TRH test during suppressive therapy with L-thyroxine.

Serum TSH was determined photometrically by a recently developed enzyme immunoassay (EIA) based on the use of a monoclonal antihuman TSH-beta antibody and a polyclonal antiTSH antibody coupled to horseradish peroxidase. The results obtained in patients with various thyroid disorders and in normal controls were compared with those achieved by conventional double antibody radioimmunoassay (RIA). In normal subjects, serum TSH was detectable in all cases by EIA (values ranging from 0.27 to 5.1 mU/L), but only in 76% by RIA. Ninety-two percent of hyperthyroids had undetectable serum TSH by EIA and the remaining 8% had values between 0.2 and 0.4 mU/L. In clinically euthyroid patients with nontoxic goiter, 9% had undetectable serum TSH by EIA, suggesting the presence of autonomously functioning areas within the thyroid. Serum TSH under basal conditions and after TRH stimulation was measured in 45 patients on L-thyroxine suppressive therapy. Undetectable basal serum TSH by EIA was associated with a lack of TSH response to TRH in 95% of cases. Conversely, 37.5% of patients with undetectable basal serum TSH by RIA had a normal or blunted response to TRH. Detectable basal values were predictive of a normal response to TRH by both methods. These data indicate that basal serum TSH measurement by EIA allows an almost complete differentiation of normal from thyrotoxic patients and can avoid the need of the TRH stimulation test.

Multi-centre study of a new CEA enzyme immunoassay using monoclonal antibodies.

The use of a new monoclonal enzyme immunoassay (EIA) for the carcinoembryonic antigen (CEA) (Enzymun-Test CEA) was evaluated in a multi-centre study. Fifteen different laboratories [participated in the study. Data from the investigation were analysed in terms of precision, sensitivity, specificity and correlation with other test methods. The intra-assay coefficient of variation was between 1.3% at 23.0 microg/l CEA and 13.9% at 1.3 microg/l CEA. Inter-assay reproducibility ranged from 3.6% to 19.2%. The apparent sensitivity of the new EIA for CEA was approx. 0.5 microg/l CEA. The findings indicate that lipaemic and haemolytic sera and samples taken from icteric, rheumatic and dialysis patients did not have any influence on the results. There was no evidence that drugs commonly used in the treatment of carcinoma patients have any influence on the assay results. A good correlation between the new EIA for CEA and six other CEA enzyme immunoassay or radioimmunoassay methods was registered. These results seem to be of significance in particular for the monitoring of therapy for carcinoma patients. The new EIA for CEA exhibits a high degree of sensitivity, specificity and reproducibility.

[Methods and clinical evaluation of a new enzyme immunologic method for determination of thyroxin binding globulin (TBG) and T4/TBG quotient: a multicenter study]. / Methodische und klinische Evaluation einer neuen enzymimmunologischen Methode zur Bestimmung des Thyroxin bindenden Globulins (TBG) und des T4/TBG-Quotienten: Eine multizentrische Studie.

A heterogeneous enzyme immunoassay for the determination of thyroxine binding globulin (TBG) was developed and assessed in clinical trials in 12 laboratories. The assay is based on the competition principle and employs plastic tubes coated with goat anti-TBG. CV's between 1.4-8.9% for intra-assay precision and 2.9-8.6% for inter-assay precision were found over the concentration range of 4-40 mg/l TBG. In comparative studies using highly purified TBG as standard, values with Enzymun-Test TBG were found to be on average 30% lower than those obtained by various TBG-RIAs. A broad-base study, to determine reference values, was carried out on a group of control persons 18 to 50 years old without previous history of thyroid disease. This study revealed a median of 14.33 mg/l TBG, with 95% of all values between 9.6 and 18.5 mg/l TBG. The median in women of 14.5 mg/l TBG was significantly higher than in men (13.4 mg/l TBG). TBG values in hyperthyroid patients were within the reference range while those in hypothyroid individuals were elevated. Highly elevated TBG values were seen in women receiving oestrogen (median: 22.2 mg/l TBG) and in pregnant women (median: 28.5 mg/l TBG). The T4/TBG ratios made it possible to distinguish between euthyroid, hyperthyroid and hypothyroic subjects (median: 4.9, 11.3 and 1.0, respectively). These ratios were significantly lower in pregnant women (median: 3.1) than in the control persons.

[Enzymatic lecithin determination in amniotic fluid for antepartal diagnosis of lung maturity - a multi-center study (author's transl)]. / Enzymatishce Lezithinbestimmung in fruchtwasser zur antepartalen Lungenreifediagnostik - Eine multizentrische Studie.

A new test-combination for the enzymatic determination of lecithin in amniotic fluid for the assessment of fetal lung maturity has been developed by Boehringer Mannheim. This test was evaluated by 12 hospitals and has been compared with the L/S ratio, the foam-test or the densitometric determination of lecithin. The assay is based on the hydrolysis of lecithin by phospholipase C which starts an enzymatic chain reaction in which NADH consumption if measured photometrically. The intra- and interassay precision were characterized by CV values below 10%. Average recoveries of lecithin were 95-102%. It is recommended to centrifuge the samples (10 min, 700 g) and to start the analysis as soon as possible after receipt of the specimen. The total amount of time required is 2 hours for a single determination. Batches of up to 10 samples require little extra time. An opened test-combination can be used for a maximum of 30 single determinations. Comparison of the quantitative enzymatic lecithin determination with other methods showed that the critical value for lecithin is 5.0 mg/100 ml. Above 5.1 mg/100 ml no case respiratory distress syndrome was observed. The good precision accuracy and the simple handling make the enzymatic lecithin determination suitable for routine use.

[Determination of glucose in hemolysed blood samples (author's transl)]. / Glucosebestimmung in hämolysierten Blutproben

The determination of glucose in hemolysed and stabilized blood samples by the hexokinase/glucose-6-phosphate-dehydrogenase-method is described. The glucose concentration in hemolysed blood samples was stable for 7 days. Even at high glucose concentrations (linear range up to 60 mmol/l), the reaction came to completion within 5 minutes. No interference by lipemia, bilirubin and drugs was observed; the interference of fructose was slight. Compared with deproteinized samples there was a very good correlation between this method and the reference method. Precision and recovery were good. This method is also suited for the analysis of few samples and offers the possibility of blood sugar self-profiles in diabetic out-patients and gives an increasing improvement of diabetic control.