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U Feldmann

Publications and source records attributed to U Feldmann.

At least 19 recordsLinked to original sources
PubMed1992

Robust bivariate errors-in-variables regression and outlier detection.

A bivariate regression model is introduced where both variables are subject to error. The structural regression line is equivariant against interchanging coordinates and permits bivariate calibration, i.e. the prediction of one variable by means of the other. Maximum likelihood and robust parameter are estimated, based on order statistics. Residual analysis and outlier detection are performed. The model is applied to the comparison of clinical chemical analytical methods.

Hematocrit↗
PubMed1991

Pharmacokinetics of 5-fluorouracil after short systemic infusion: plasma level at the end of the distribution phase as an indicator of the total area under the plasma concentration-time curve.

The correlation between single plasma concentration (CP) values of 5-fluorouracil (FU) after a 10-minute i.v. infusion and the total area under the plasma concentration-time curve (AUC) has been studied in 26 cancer patients. FU dose was either 320-550 mg/m2 (seven patients, 13 treatments) or 610-960 mg/m2 (19 patients, 30 treatments). Linear single CP-AUC relationships were found in both dose groups with the CPs at 1, 5, 10, 15, and 30 minutes after the end of infusion. Parameters of linear regression of AUC on single CP differed between the two dose groups. For the high-dose group, the single CPs at repeated treatments were tested as estimators of the total AUC at these treatments, using calibration lines relating total AUC to single CP, which were derived from the data of the first (or only) treatments of all patients. The "best" AUC estimators of the total AUC were the CPs at 10 and 15 minutes after the end of infusion, with a bias of only 2% and an imprecision of only 11% of the AUC values directly determined from the complete concentration-time profiles of the repeated treatments. Because of the close correlation between these single CPs and the total AUC, these CPs should be considered equivalent to the AUC as an overall index of individual FU kinetics after brief infusion of high doses.

Adult↗
PubMed1989

Significance of latent hyperthyroidism.

In euthyroidism the circadian rhythm and pulsatility of TSH is well known. With regard to hyperthyroidism only very preliminary data were described. In this study we investigated the secretion pattern of the pituitary-thyroid axis hormones during 24 h in latent and overt hyperthyroidism and in euthyroidism with regard to common and different properties. Blood was obtained for 24 h at 10-min intervals. In euthyroidism we found intraindividually three overlapping patterns of TSH, which are different in amplitude and frequency and can be found interindividually, too. These patterns are equal to the circadian rhythm, pulsatile secretion and lastly to the methodic rustle. The circadian rhythm in latent hyperthyroidism is distinctly suppressed and in overt hyperthyroidism totally. Whereas in latent hyperthyroidism pulsatile secretion is extant, in overt hyperthyroidism the TSH pulses are absent. To record the patients' TSH circadian rhythm with only three blood samples, we defined the TSH-Triplex. In young as well as in elderly healthy volunteers it demonstrated significantly higher TSH levels at midnight (at 24:00 h) than it did at 4 p.m. and 8 a.m. The present study shows a significantly different TSH pattern in latent hyperthyroidism compared to euthyroidism. It should be discussed whether latent hyperthyroidism could be defined as hyperthyroidism stage I. On the other hand, latent hyperthyroidism could be an illness with its own cause, different from hyperthyroidism. Our data suggest that the laboratory findings of latent hyperthyroidism in each age are non-physiological. However, the cause for this disorder is unclear until now; hence further investigations are necessary.

Adult↗
PubMed1987

[Effect of 10% hydroxyethyl starch 200/0.5 and 10% dextran 40 on the flow property and coagulation of whole blood in vivo].

In randomized order 18 hypovolemic patients undergoing minor surgery received either 500 ml of 10% dextran 40 (n = 8) or 500 ml of 10% hydroxyethylstarch 200/0.5 (n = 10) preoperatively. There were no significant changes in hemoglobin, hematocrit, colloid osmotic pressure, total serum protein, platelet count, platelet aggregation and hemostatic tests. The shear dependent viscosity of whole blood was determined at the relevant range of 1.24-91.0 s-1. Both colloids cause a marked decrease of whole blood viscosity, which is detectable at low shear rates still 24 h later. Plasma viscosity shows no changes in either group. The criteria for preferring one of the colloids for decreasing the blood viscosity will depend on the incidence and severity of undesired adverse reactions.

Adult↗
PubMed1987

[The Mannheim peritonitis index. An instrument for the intraoperative prognosis of peritonitis].

Based on the experience with 1243 patients suffering from purulent peritonitis 255 patients of two surgical departments were studied prospectively in a cohort study. Lethality was 24%. For intraabdominal infection an index is established that allows for the first time to predict lethal outcome of the disease in the individual patient. For each index-score the expected mortality is given by a modern mathematical calculation. The 'Mannheim Peritonitis Index' includes only clinical risk-factors that are routinely documented pre- and intraoperatively. Methods of evaluation, validation and the comparison with other prognostic indices are presented.

Humans↗
PubMed1986

[Differential diagnosis of jaundice by combined noninvasive diagnostic means using a logistic discriminant analysis].

Using a logistic discriminant function we retrospectively evaluated the diagnostic value of laboratory features and abdominal sonography in 70 patients with jaundice. 18 patients had an extrahepatic obstruction of the common bile duct (EHO), 22 patients had metastatic liver disease (MLD) and 30 patients had an infectious or toxic hepatocellular disease (HCD). The sensitivity resp. specificity of the 5 laboratory values AP, GGT, GPT, GOT and bilirubin was 22% resp. 90% for diagnosing EHO, 82% resp. 79% for diagnosing MLD and 67% resp. 68% for diagnosing HCD. The diagnostic value determined by their Chi2-value was AP greater than GPT greater than bilirubin greater than GOT greater than GGT. An undoubtedly dilated common bile duct was seen in 56% of the patients with EHO and in none of the other patients. Metastatic lesions were seen exclusively in 81% of the patients with MLD. No distinct sonographic sign could be found for the patients with HCD. The combination of AP, GPT and bilirubin with the result of abdominal sonography in a logistic discriminant function led to a correct a posteriori classification of all patients. Using a mathematical classification model jaundiced patients can be diagnosed on the basis of noninvasive methods alone and invasive procedures should be restricted to therapeutic interventions.

Cholestasis, Extrahepatic↗
PubMed1979

Biochemical characteristics of Ehlers-Danlos syndrome type VI in a family with one affected infant.

The parents of a child with the clinical symptoms of Ehlers-Danlos syndrome type VI were identified as third-degree cousins. Biochemical analysis of the dermis of the patient revealed a complete lack of hydroxylysine in the dermal collagen. The dermis of both parents contained only half the amount of hydroxylysine found in healthy individuals. Hydroxylation of prolyl residues was normal in the skin of the patient and his parents. Investigation of the collagen synthesized by fibroblasts derived from the skin of the patient showed a normal proportion of type I and type III collagen. However, while hydroxylation of prolyl residues was normal in type I and type III collagen, hydroxylation of lysyl residues was markedly lower than normal in both type I and type III collagen.

Collagen↗
PubMed1979

Comparison of 9 methods for the determination of cholesterol.

Seven enzymatic procedures for the determination of cholesterol in serum were compared with the Liebermann-Burchard- and a gas-chromatographic method. Using a decision matrix all methods could be ranked according to reliability and practicability . With the exception of the cholesterol oxidase-coupled Kageyama principle and the Liebermann-Burchard procedure, all the other methods showed similar reliability.

Autoanalysis↗
PubMed1979

Studies on the methodology and evaluation of the lymphocyte transformation microtest.

Optimum experimental conditions for the lymphocyte transformation microtest in healthy persons are described. The dependence of PHA stimulation on duration of culture, additions of serum and PHA concentration is investigated. A function of normal distribution pattern can be set up by determining the lymphocyte stimulability with four different PHA concentrations in the optimal stimulation range. With this function, the area under the curve, steepness, position and height of the maximum can be calculated. These parameters should serve for better interpretation of cellular immunity.

Adult↗
PubMed1975

HL-A antigens in carcinoma of the breast, ovarium, cervix and endometrium: possible association of haplotype HL-A10-W18 with carcinoma of the breast.

24 HL-A antigens were determined in a total of 163 Caucasien cancer patients (60 breast cancers, 64 cancers of the cervix uteri, 19 cancers of the endometrium and 20 cancers of the ovary). The comparison of the antigen frequencies with the analogous values from 1000 healthy controls yielded no outstandingly significant deviations for cancer of the cervix, endometrium and ovary. In breast cancer patients, however, there might be an association with the antigens HL-A10 and W18 or the haplotype HL-A10-W18, as indicated by the results of a combined evaluation of our data together with the results of four different HL-A studies in breast cancer patients.

Breast Neoplasms↗