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Biomedical subjects

P M Bayer

Publications and source records attributed to P M Bayer.

At least 19 recordsLinked to original sources
PubMed1995

Precision and accuracy of monocyte counting. Comparison of two hematology analyzers, the manual differential and flow cytometry.

The Coulter STKS (Coulter, Hialeah, FL), the Abbott CD3500 (Abbott Diagnostics, Abbott Park, IL), a 400-cell manual differential, and flow cytometry using double-staining with fluorescence-labelled monoclonal antibodies (CD45-FITC and CD14-PE) on a Coulter Epics Profile II were evaluated for precision and accuracy in relative monocyte counting. STKS, CD3500, and Profile II achieved a precision analogous to a 3,542-, 1,835-, and 11,998-cell differential, respectively, demonstrating the superiority of automated methods. Analysis of 156 normal and abnormal samples revealed that the mean relative monocyte counts of the manual differential, CD3500 and Profile II were not significantly different. Only the STKS results showed a positive bias (0.79% +/- 1.65), which was increased in lymphocytic samples. Linear regression between the Profile II as independent viable, and the other techniques yielded acceptable correlation coefficients (STKS: 0.861, CD3500: 0.844, manual differential:0.833). Profile II results were also compared to those of a Becton Dickinson FACScan (Becton Dickinson, Mountain View, CA), which yielded an excellent correlation (r = 0.991) but a slightly smaller relative monocyte count (bias-0.39% +/- 0.60) of the latter. On the basis of these data, the authors recommend the use of monoclonal antibodies as a new reference method, but also indicate the need for further methodological investigations.

Antibodies, Monoclonal↗
PubMed1992

Multiple occurrence of macro creatine kinase in one family.

We measured creatine kinase (CK, EC 2.7.3.2), CK-MB isoenzyme activity and mass concentration, and distribution of CK isoenzymes (by electrophoresis) in serum from five members of one family. The mother and two young children showed CK-IgG complexes in their sera. The concentration of the CK-IgG complexes in the children decreased over time, suggesting that the complex involved maternal IgG and had been transferred across the placenta from the mother to her children.

Adult↗
PubMed1991

New method for the determination of pancreatic amylase evaluated.

We have carried out a multicenter evaluation of a new reagent carrier for Reflotron, specific for pancreatic amylase where the salivary isoenzyme is inhibited by two specific monoclonal antibodies. This new procedure combines easy handling with low imprecision (median CV less than 3%) in control material, serum, heparinized blood, and plasma) and close correlation (r = 0.991 to 0.999) with established manual and automated methods. The same close correlation was found with values obtained from either venous or capillary finger-stick blood. Salivary amylase up to 54 kU/L (37 degrees C) was inhibited to about 97%. Endogenous interference by hemoglobin, bilirubin, triglycerides, cholesterol, or hematocrit was found to be negligible within a wide range of interferent concentrations. Out of a panel of 28 commonly used drugs it was shown that only two (ascorbic acid and paracetamol), and then only at toxic concentrations, caused a deviation in amylase activity of greater than 10%. From the results of this study we conclude that this new method is suitable for highly precise and accurate measurements of pancreatic amylase in emergency and routine laboratories.

Amylases↗
PubMed1990

Multicentre evaluation of the Boehringer Mannheim/Hitachi 717 analysis system.

We conducted an European multicentre trial to assess the performance of the new Boehringer Mannheim/Hitachi 717 analysis system. The photometer response was linear up to an absorbance of 2.8. The maximal CV of photometric imprecision was 0.5% for the wavelength pair 340/405 nm within the absorbance range 0.9 to 2.4. For the 13 analytes in our study, mean within-run imprecision was less than 2%, and mean between-day imprecision less than 2.5%. The results obtained with the Hitachi 717 instrument correlated closely with those of comparison instruments. Linearity for the various tests was high and exceeded the manufacturer's claims. No drift was detected during an 8-hour work period; carry over could not be detected under the chosen experimental conditions. The new instrument was readily accepted by the evaluators because of its ease of handling and simple daily maintenance.

Blood Chemical Analysis↗
PubMed1989

Alpha-amylase determination with the Reflotron reagent carrier system: use of whole blood, plasma, and serum, and effect of isoenzymes.

In the Reflotron Amylase dry-reagent carrier system (Boehringer Mannheim GmbH) a new substrate is used for determining total amylase (EC 3.2.1.1) activity:indolyl-alpha-D-maltoheptaoside. The procedure shows low imprecision (median CV less than 3.2%), and results for sera, plasma, and capillary and venous blood (y) correlate well with those of a conventional alpha-amylase method involving p-nitrophenyl (PNP)-maltoheptaoside substrate (x) (for 209 blood samples: y = 0.981x + 9.7; r = 0.994). Correlation was also excellent with a method involving maltotetraose as substrate (r = 0.987). Attachment of an indoxyl residue rather than a PNP group to the maltoheptaoside did not affect the substrate response to pancreatic or salivary isoenzyme activity. Therefore, the relative proportion of these isoenzymes did not affect the correlation between the Reflotron Amylase reagent carrier and the alpha-amylase PNP-maltoheptaoside method. With a reaction time of less than 3 min, this system is especially suitable for amylase determination in situations where a prompt result is required.

Humans↗
PubMed1988

Neutrophil elastase alpha 1-proteinase inhibitor complexes in pleural effusions.

Polymorphonuclear (PMN) granulocyte derived neutrophil elastase (NE) is rapidly antagonized by alpha 1-proteinase inhibitor (alpha 1 PI) in vivo. To determine the clinical value of elastase alpha 1-proteinase inhibitor complexes (E-alpha 1 PI) in pleural effusions, fluid samples of 99 patients were examined. Fifty-six had malignant effusions, 30 had non-malignant exudates (pleural protein above 3 g/dl) mainly of inflammatory origin, and 13 patients had low protein transudates (below 3 g/dl) due to congestive heart failure. Nonmalignant exudates showed significantly higher (P less than 0.001) concentrations of E-alpha 1 PI compared with malignant effusions or low protein transudates (P less than 0.001). Malignant exudates secondary to lung cancer were characterized by higher (P less than 0.001) median pleural E-alpha 1 PI concentrations compared to malignant exudates due to primarily extrathoracic malignancies. Total pleural leukocyte counts and pleural neutrophil counts were performed in 68 effusions. By this means no clear-cut differentiation between malignant and nonmalignant exudates seems possible except for marked empyema. In conclusion, E-alpha 1 PI complexes in pleural fluid may better reflect the stage of inflammation of pleural effusions rather than mere pleural leukocyte counts. Low levels of E-alpha 1 PI complexes (less than 75 ng/ml) in pleural exudates with protein values above 3 g/dl are characteristic of malignant exudates. Determination of E-alpha 1 PI in pleural exudates may serve as a sensitive marker of inflammation and useful adjunct to pleural cytology in aspects of differential diagnosis of pleural effusions.

Blood Proteins↗
PubMed1987

A multicentre evaluation of the Boehringer Mannheim/Hitachi 704 analysis system.

The selective multitest Boehringer Mannheim/Hitachi 704 analysis system was examined according to the ECCLS guidelines in a multicentre evaluation involving four laboratories. Ten routine parameters, covering most of the application settings of the instrument, were measured in the respective laboratory at temperatures 25, 30 or 37 degrees C. The trial lasted four months and gave more than 40,000 data. It yielded the following results: 1. Within the four laboratories the mean coefficients of variation for three control sera at different concentrations were found to be equal to or better than 1.6% for the within-run imprecision and 2.8% or better for the between-day imprecision. 2. No drift was observed during eight hours. 3. Because of the high linear measuring range a re-run analysis was seldom necessary. 4. Sample-related carry-over was not seen. Reagent-dependent carry-over was measured from cholesterol to uric acid and from triacylglycerols to lipase. Through modification of the cholesterol and triacylglycerol reagents, the carry-over effect was practically eliminated. 5. The recovery of the assigned values of control sera showed average values between 99 and 104%. For bilirubin, creatinine, creatine kinase and alanine aminotransferase some control sera showed deviations greater than 10%. 6. In all cases, regression analysis of the results obtained in comparisons of the present instrument with the Hitachi 705 or 737 yielded slopes close to unity with extreme values of 0.95 and 1.06. 7. During the entire evaluation period there was no malfunction or breakdown of the instruments. The evaluators came to the conclusion that the analytical performance as well as the reliability and practicability of the Hitachi 704 can be rated as excellent.

Autoanalysis↗
PubMed1986

[Diagnostic value of the combined determination of carcinoembryonic antigen (CEA) in pleural effusion and serum with an enzyme immunoassay (EIA). Sensitivity, specificity and relation to tumor type].

Measurement of carcinoembryonal (CEA) levels in pleural fluid are suggested to improve the unsatisfactory sensitivity of pleural cytology in the differential diagnosis of malignant pleural effusions. We evaluated simultaneously determined pleural and serum CEA levels in 117 patients with pleural effusions of different aetiology (74 malignant, 30 inflammatory exudates and 13 transudates) by use of an enzyme immunoassay (EIA). Despite considerable scatter, pleural levels of CEA in malignant effusions were significantly higher (p less than 0.001) than the values in benign effusions. Using a cut off level of 5 ng/ml, 41% (= sensitivity) of malignant pleural effusions showed elevated concentrations of CEA. Only one out of 43 benign effusions showed a level of 5 ng/ml, which is equivalent to a specificity of 98%. However, malignant effusions due to small cell lung cancer, pleural mesothelioma and metastasising ovarian carcinoma never showed elevated levels of CEA. Highest pleural values of CEA were observed in cases of alveolar cell or adenocarcinoma of the lung or metastasising breast cancer. Although pleural and serum CEA levels correlated significantly (rs = 0.77), the evaluation of serum CEA levels alone yielded a lower sensitivity (36%) and specificity (93%) than pleural levels. 77% of cases with malignant pleural effusions showing elevated pleural CEA levels were characterized by an increased ratio Pleura/Serum greater than 1, particularly in effusions due to lung cancer. The CEA ratio was significantly higher (p less than 0.05) in patients with malignant than with benign effusions. EIA appears to be more specific by avoiding false positive results in benign effusions as compared with determination by conventional RIA. In conclusion, evaluation of pleural CEA levels in patients with malignant effusions by using an EIA because of its high specificity is a valuable adjunct to pleural cytology in improving the diagnosis of malignant effusions. However, a normal CEA level in either pleural effusion or in serum is of no clinical significance. Simultaneous measurement in pleural effusion and serum is of greater value.

Breast Neoplasms↗
PubMed1984

[Hematologic changes in patients under long-term hemodialysis and hemofiltration treatment with special reference to serum concentrations of folic acid and vitamin B 12].

The incidence of macrocytic anemia has been investigated in 32 patients on maintenance hemodialysis (mean age 46 years, mean duration of dialysis treatment 27.5 months), in 18 patients with combined hemodialysis (HD) and hemofiltration (HF) treatment (mean age 42 years, mean duration of combined HD and HF treatment 6.3 months) and in 32 patients after renal transplantation (mean age 41 years, mean observation period since successful renal transplantation 55.2 months). Also investigated were serum levels of vitamin B12 (radioassay kit 57Co) and folic acid (radioassay kit 125J). Macrocytosis (MCV greater than 96 fl) was observed in 38% of the patients on maintenance hemodialysis, in 44% of the patients with combined HD and HF treatment, and in 47% of the renal transplant recipients. In the chronically dialysed patients, in contrast to the patients with combined HD and HF treatment, the mean serum folic acid level was significantly lower (p less than 0.005) than that of healthy controls. Serum levels of vitamin B12 were within the normal range in all patients. There were no significant differences in serum levels of folic acid and vitamin B12 between the patients with MCV greater than 96 fl and MCV less than or equal to 96 fl. Nor was there a correlation between the serum levels of folic acid or vitamin B12 and mean corpuscular volume. These results suggest that folic acid deficiency is of minor importance in the complex pathogenesis of anemia in hemodialysed patients.

Adult↗
PubMed1983

Adenylate kinase activity of cerebrospinal fluid in central nervous system disorders.

Adenylate kinase activity was measured in 41 samples of cerebrospinal fluid in 34 patients with various neurological disorders or psychiatric symptomatologies. Activities of the enzyme showed to be linked to clinically estimated acuteness or progression of the changes in the central nervous system at the time of specimen collection. The findings suggest the conclusion that determination of adenylate kinase activity in cerebrospinal fluid is a meaningful tool for the evaluation of progression and/or acuteness of central nervous system disorders.

Adenylate Kinase↗
PubMed1982

[Variant creatine kinase isoenzymes: frequency and clinical significance (author's transl)].

To estimate the incidence of variant creatine kinase (CK)isoenzymes, 1,191 unselected patients were screened by means of CK:CK - MB ratio. When CK - MB was higher than 20% of the total CK in the immunoinhibition test, and a myocardial infarction could be excluded, a CK-isoenzyme electrophoresis was performed. We found macro-CK-BB-emia in 13 patients, but only three of them had elevated total CK activity. All patients but two were at the typical age of over 60 years; two males were 2 and 9 years old. The clinical diagnosis in macro-CK-BB-emia was predominantly cardiocerebrovascular insufficiency due to arteriosclerosis. In 16 other patients, the presence of an isoenzyme migrating cathodically to CK-MM was found. In this group, a malignant metastatic tumor was found in eight cases, the rest predominantly suffered from severe liver disease. Presence of both variant CK isoenzymes may lead to diagnostic or therapeutic errors due to the altered CK:CK-MB ratio. According to our studies, a variant CK isoenzyme occurs in 2.6% of hospitalized patients, but this will lead to problems diagnosing acute myocardial infarction only in the group with elevated total CK (0.42% of our patients).

Aged↗
PubMed1982

Immunoreactive trypsin, alpha-amylase and lipase in serum--is there an age-dependence?

A strong age-dependence of IR trypsin was found in 424 healthy controls suggesting the need for age-matched reference values. A possible relation of other exocrine pancreatic enzymes like alpha-amylase and lipase to age was investigated in 185 apparently healthy persons undergoing a preventive health check. Only alpha-amylase showed a weak correlation with age, but not lipase. Both enzymes correlated with IR trypsin. Whilst alpha-amylase and lipase activities were within the normal range, approximately 25% of IR-trypsin concentrations were above age-matched control values. It is suggested that these apparently healthy persons already have disease of the exocrine pancreas, and IR trypsin is a more sensitive diagnostic tool for screening than alpha-amylase or lipase.

Adolescent↗
PubMed1982

Evaluation of a monitor guided nephelometric system.

The most common parameters in the specific protein field, namely the immunoglobulins G, A and M were investigated on the recently developed Immuno Video Nephelometer System (IVNS). This system consists of the nephelometer, a microprocessor controlled program and a monitor screen, where instructions, standard curve and results are displayed. Scattered light of immuno-complexes is measured at equilibrium after incubation of prediluted antigen-antibody mixtures. Data were compared with those obtained by radial immunodiffusion (RID), rate nephelometry (Beckman Immunochemistry System-ICS) and immunoturbidimetry (ENI-Gemsaec). Intrabatch variation on the Immuno Video Nephelometer System was found to be good (CV-2.6-3.7%) and day to day variation was satisfactory (CV-3.3-8.6%). There was also good correlation between the values found on the Immuno Video Nephelometer System and those of the other methods (correlation coefficient of 0.94-0.98). Instrumentation advantages, operation procedure and necessity of antigen excess check are discussed in detail.

Animals↗
PubMed1982

Immunoinhibition and automated column chromatography compared for assay of creatine kinase isoenzyme MB in serum.

We examined sera from six different groups of patients for CK-MB activity by means of two commercially available tests, an immunoinhibition method (E. Merck) and the CK-MB test as used with the aca (Du Pont). In the first group of patients (suspicion of myocardial infarction) the correlation between the two methods was good: r = 0.9191, y = 1.068x -- 0.888, x = 18.7 U/L, y = 19.0 U/L. In the second group, patients with high adenylate kinase activity, no interference was detectable on the aca, whereas the immunoinhibition method yielded falsely high CK-MB values. The third group consisted of persons with macro-CK-BB in their serum. In the immunoinhibition test these patients usually showed a high CK-MB:total CK ratio, whereas such results were rarely found for the aca. The fourth group, patients with a different electrophoretic mobility of their CK-isoenzymes (migration of an active band towards the cathode), were detected by the immunoinhibition method (high ratio of CK-MB to total CK), but not with the aca. In the presence of free CK-BB (group five) the immunoinhibition test resulted in "falsely" high CK-MB values, whereas CK-BB was retained on the column of the aca. In skeletal muscle diseases (group six) results by the two methods differed, values for CK-MB on the aca being much higher. It was demonstrated experimentally that this was due to CK-MM with altered surface charge.

Adenylate Kinase↗