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Biomedical subjects

D Vonderschmitt

Publications and source records attributed to D Vonderschmitt.

10 recordsLinked to original sources
PubMed1995

Lung tumor cells: a multivariate approach to cell classification using two-dimensional protein pattern.

High resolution two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) is a powerful research tool for the analytical separation of cellular proteins. The qualitative and quantitative pattern of polypeptides synthesized by a cell represents its phenotype and thus defines characteristics such as the morphology and the biological behavior of the cell. By analyzing and comparing the protein patterns of different cells it is possible to recognize the cell type and also to identify the most typical features of these cells. In applied pathology it is often difficult to identify the tissue of origin and the stage or grade of a neoplasia by cellular morphology analyzed by classical or immunostaining procedures. The protein pattern itself is the most characteristic feature of a cell and should therefore contribute to the identification of the cell type. For this reason we separated protein fractions originating from different lung tumor cell lines using 2-D PAGE and we compared the resulting patterns on a multivariate statistical level using correspondence analysis (CA) and ascendant hierarchical clustering (AHC). The results indicate that (i) protein patterns are highly typical for cells and that (ii) the comparison of the protein patterns of a set of interesting cell types allows the identification of potentially new marker proteins. 2-D PAGE is thus a unique and powerful tool for molecular cytology or histopathology, unveiling the protein expression level of tissues or cells.

Adenocarcinoma↗
PubMed1991

A computer controlled device to facilitate studies of the kinetics of ligand-binding: binding of diazepam to bovine brain membranes.

A device to facilitate kinetic receptor filtration assays is described. The receptor containing membranes and the labeled ligand are placed in two separate syringes and are rapidly mixed into a collecting syringe using a pneumatic ram. Shortly after the start of mixing, a pneumatically controlled valve switches the collecting syringe containing the receptor-ligand mixture to the filtration unit. Filtration is performed on glass/microfiber filters or equivalent by pushing the plunger of the collecting syringe by a stepper motor. A valve positioner controlling several valves allows the filtered membranes to be washed and dried by pressure in any user programmable sequence. Further filtration of the receptor-ligand mixture can be programmed at selected time points. The entire system is controlled by an IBM-PC. With this system, the association and dissociation of diazepam from crude bovine-brain membranes has been studied at 4 degrees C. The dissociation shows a biphasic pattern with half lifes of 1.3 and more than 23 minutes respectively. Association appears to be into a single compartment.

Animals↗
PubMed1991

European multicentre evaluation of the Du Pont Dimension 380 under the auspices of the European Group for the Evaluation of Analytical Systems in Laboratory Medicine (EGE-Lab).

The Clinical Chemistry Analyzer Dimension 380 manufactured by Du Pont de Nemours was tested in a multicentre evaluation according to the guide-lines of the European Committee for Clinical Laboratory Standards (ECCLS) and in part to the protocol of the Société Française de Biologie Clinique (SFBC). The instrument and the reagents were evaluated as a system, since both reagents and reagent cartridges are specifically designed for the instrument. Fourteen analytes including electrolytes, substrates and enzymes were tested. The evaluators summarized their experience as follows: 1. All parameters tested yield results comparable to established procedures. 2. Very good performance of the ion-selective-electrode unit. 3. The imprecision data of the system are, for most parameters, between 1 and 4% CV and thus equal to or better than those of the instruments compared. 4. No reagent or sample carry-over was detected after a minor modification of the instrument. 5. The linearity of Dimension test methods in general covers the range stated by the manufacturer. 6. Very good stability of the calibration curves (up to 2 months). 7. Good practicability of the whole system, including handling of reagents and a very user-friendly software.

Blood Chemical Analysis↗
PubMed1981

[Evaluation of test strips for the semi-quantitative screening for proteinurias (author's transl)].

Commercial test strips using the protein error of certain indicators for the colorimetric detection of protein (especially albumin) were compared with a quantitative nephelometric method. The study proved that there is good agreement between the results from the quantitative method and those from the test strips (Rapignost Protein/Combur-8-Test). Both test strips generally shoed a good separation of the segments for semi-quantitative determinations. There was a very good agreement between the test strips in protein-containing urines. In protein-free urines, however, the Combur-8-Test showed a slightly higher proportion of false-positive results.

Colorimetry↗
PubMed1978

[Diagnostic value of the myocardium-specific isoenzyme creatinephosphokinase (CK-MB)].

In 150 ambulatory and 155 hospitalized patients the normal values for creatine phosphokinase (CK) and the isoenzyme CK-MB were determined using a simple test with inhibiting antibodies. In a series of 100 consecutive patients hospitalized for chest pain, CK-MB was measured over a 72-hour period in 6- to 12-hourly intervals. The results were compared to the clinical findings, ECG, total CK and SGOT. In addition, CK-MB was determined after elective DC countershock and intramuscular injections (12 patients in each group). Normal values for CK-MB were found to be less than or equal to 10 U/1 in all patients, whereas the values for total CK turned out to be male less than 125 U/1, female less than 100 U/1 in ambulatory patients and less than 50 U/1 in hospitalized patients. In 68 of the 100 patients hospitalized for chest pain, acute myocardial infarction was found. The specificity of CK-MB in patients with transmural infarction was calculated as 100%, and the sensitivity as 97%. After DC countershock and intramuscular injections, CK was markedly elevated whereas CK-MB only rose after cardioversion. We conclude that CK-MB may be of considerable value for the differential diagnosis of elevated total CK activities of unknown origin. It is a very specific and a sensitive parameter for the diagnosis and exclusion of acute myocardial infarction.

Creatine Kinase↗
PubMed1976

Oral administration of a chymotrypsin-labile peptide--a new test of exocrine pancreatic function in man (PFT).

One gram N-benzoyl-L-tyrosyl PABA was orally administered to 24 controls, 15 patients with chronic exocrine pancreatic disease, 13 patients after an attack of acute pancreatitis, two patients with gluten-sensitive enteropathy, and 10 patients with biliary tract disease, peptic ulcer, or other pathology of the gastrointestinal tract. In the presence of chymotrypsin, PABA is split from the peptide and excreted in the urine. The amount of PABA excreted serves as a parameter of exocrine pancreatic function. In 51 patients, exocrine pancreatic secretion was also assessed by the Lundh test. In the control group a mean of 59-6 +/- 12-2% (mean +/- 2 SD) of the peptide-PABA was excreted over a period of six hours. PABA excretion in exocrine pancreatic deficiency was significantly less (P less than 0.001) than in controls. With one exception no overlap of data was noted. In the group with exocrine pancreatic deficiency, a significant relationship was shown between the PFT and the Lundh test. Reproducibility in duplicate test was excellent. The present data justify further investigations of this procedure as a possible new oral test of exocrine pancreatic function.

Adult↗
PubMed1975

[First experiences with a new oral human pancreas function test with special emphasis on gastric voiding].

1 g of N--benzoyl-L-tyrosyl-PABA was administered orally to 50 test persons, i.e. controls and patients with known pancreatic disease. In the presence of chymotrypsin, paraaminobenzoic acid (PABA) is split from the peptide and excreted in the urine. The amount of PABA excreted serves as parameter of exocrine pancreatic function. In the control group a mean of 59.2 +/- 6.2% of the peptide PABA was excreted over a period of 6 h. PABA excretion in exocrine pancreatic deficiency was significantly less (p less than 0.001) than in controls. No overlap of data was noted. Gastric emptying rate - estimated by using indium-113m microcolloid - did not appear to influence urinary PABA excretion.

Administration, Oral↗