| 11. |
- Hultberg, Björn, et al.
(författare)
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The association between plasma beta-hexosaminidase and its isoenzyme patterns and retinopathy in type 1 diabetes mellitus
- 1991
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Ingår i: Clinica Chimica Acta. - 0009-8981. ; 196:2-3, s. 177-183
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Tidskriftsartikel (refereegranskat)abstract
- beta-Hexosaminidase and its isoenzyme patterns were investigated in plasma from patients with Type 1 diabetes mellitus. The patients were divided into three main groups matched for duration of diabetes: (a) proliferative retinopathy (b), progress of retinopathy within a two-year period (c) and with no background retinopathy. When all patients were compared to a reference group, a significant increase of plasma beta-hexosaminidase activity was found. Patients with proliferative retinopathy had significantly increased activity of plasma beta-hexosaminidase compared to the reference group but not compared to the other diabetic patients. The isoenzyme distribution was not different in any of the diabetic subgroups compared to the reference group. It was also shown that various degrees of diabetic nephropathy did not influence total plasma Hex or the isoenzyme pattern.
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| 12. |
- Karlsson, Mats G., 1960-, et al.
(författare)
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Quantitative computerized image analysis of immunostained lymphocytes : A methodological approach
- 1994
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Ingår i: Pathology, Research and Practice. - München, Germany : Elsevier. - 0344-0338 .- 1618-0631. ; 190:8, s. 799-807
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Tidskriftsartikel (refereegranskat)abstract
- A methodological approach by computerized image analysis to quantify immunostained objects in histological sections is described. We have investigated antibodies against CD4, CD8, CD20, CD23 and CD25 in frozen sections of human nasal mucosa; however, the methodology of standardization is of general validity. The study was designed particularly to investigate the following points: 1) light intensity, 2) the grey level for counter staining intensity, 3) the grey level threshold value for positive objects, 4) the minimal acceptable size of a positive object, 5) the influence of the brightness of the light on both the number and the area of objects. Furthermore, random sampling and determination of 6) the area per section, and 7) the number of histological sections to be measured per biopsy. Finally, a study of reproducibility of immunostaining intensity was performed. The influence of the different parameters mentioned above was studied and the values (eg. threshold value) for our particular setting of microscope, image analysis equipment, computer software etc, were defined. The method was then tested for intra- and interindividual variation which was found to be less than 5%. Correlation analysis of the reproducibility gave coefficients of correlation of 0.99, both concerning number of immunopositive objects and immunopositive area. We emphasize the importance of a highly standardized methodology if the numeric data obtained from computer assisted image analysis are to be more accurate than semiquantitative assessments by experienced observers. With a thorough standardization as described in this method it is possible to obtain numeric values, and data with low deviations, which are two obvious and important advantages.
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| 13. |
- Lubenow, Norbert, et al.
(författare)
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Phenylketonuria screening with a fluorometric microplate assay.
- 1994
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Ingår i: European journal of clinical chemistry and clinical biochemistry : journal of the Forum of European Clinical Chemistry Societies. - 0939-4974. ; 32:7, s. 525-8
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Tidskriftsartikel (refereegranskat)abstract
- A fluorometric assay in microtitre plates for the screening of phenylketonuria was evaluated and adapted to a neonatal screening programme. Using this assay, it is possible to determine quantitatively the phenylalanine concentration in dried blood spots on filter paper. The test exhibited a linear calibration curve with a good slope as well as sufficient precision and accuracy in the statistical analysis. Interference by other amino acids and antibiotics was not observed. Only elevated concentrations of leucine interfered to a small degree. The phenylalanine concentration in dried blood spots of 13 phenylketonuria patients correlated to that in serum. 7381 dried blood samples of newborn infants were tested simultaneously by both the fluorometric and the Guthrie test. The results did not show significant differences. We screened 29,182 newborns using the fluorometric assay and an online data processing programme. The internal repetition rate was 0.64%, the external recall rate 0.15%. False negative results were not observed. In December 1991 the fluorometric method replaced the Guthrie test in our routine programme for phenylketonuria screening, and was introduced as a follow up test for phenylketonuria patients.
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| 14. |
- Torffvit, Ole, et al.
(författare)
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Tubular secretion of Tamm-Horsfall protein in type 1 (insulin-dependent) diabetes mellitus using a simplified enzyme linked immunoassay
- 1992
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Ingår i: Clinica Chimica Acta. - 0009-8981. ; 205:1-2, s. 31-41
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Tidskriftsartikel (refereegranskat)abstract
- The relationship between glomerular and tubular dysfunction and metabolic control in type 1 diabetes was studied. To that end the urinary excretion rates of albumin and Tamm-Horsfall protein as well as HbA1c levels were measured in 58 patients with different degrees of diabetic nephropathy and in 76 apparently healthy subjects matched for sex and age. The urinary Tamm-Horsfall protein levels were measured by a simplified enzyme linked immunoassay. The intra- and interassay variations were 8.9% and 13.6%, respectively. The intraindividual variation was 41% and the sensitivity of the assay was 4 micrograms/l. The Tamm-Horsfall protein excretion rate was 42.1 x/2.0 micrograms/min (geometric mean x/tolerance factor) in the diabetic patients compared to 34 x/1.9 micrograms/min in the control subjects (NS). The diabetic patients had higher albumin excretion rate (38.5 x/7.3 micrograms/min) than the control subjects (4.7 x/2.3 micrograms/min; P less than 0.001). By using multivariate analysis of variance, HbA1c level was found to be the only independent variable associated with Tamm-Horsfall protein excretion rate in diabetic patients (r = -0.28; P = 0.04), while no relationship was found between Tamm-Horsfall protein excretion rate and age, age at onset and duration of diabetes, gender, serum creatinine, diuresis, urinary albumin excretion rate, systolic and diastolic blood pressure levels and antihypertensive treatment. The urinary albumin excretion rate was associated with diastolic blood pressure (r = 0.34; P = 0.02) but not with HbA1c levels when testing the above variables by multivariate analysis of variance. In conclusion, these results may indicate a lack of relationship between glomerular and tubular dysfunction. The former was influenced only by diastolic blood pressure levels and the latter only by the degree of metabolic control. However, the correlations were weak and do not provide any insight into what is actually responsible for glomerular and tubular dysfunction.
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