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Biomedical subjects

H Kahle

Publications and source records attributed to H Kahle.

7 recordsLinked to original sources
PubMed1995

Flow cytometric determination of aminopeptidase activities in viable cells using fluorogenic rhodamine 110 substrates.

Aminopeptidases (AP) are ubiquitously occurring, nonspecific exopeptidases involved in protein degradation. They cleave the N-terminal amino acid of peptides and occur in practically all mammalian cells and tissues. Physiological and pathological processes such as metastasis of tumors and inflammation have been thought to involve changes in AP activities. Determination of AP (EC 3.4.11.X) activity in viable cells by flow cytometry was the subject of this study because of its general biological and clinical interest. Different bis-substituted rhodamine 110 (R110) peptide derivatives were synthesised and used as AP- and exopeptidase (EC 3.4.13.X-EC 3.4.14.X) substrates for flow cytometric measurements. Intracellular AP activities in viable lympho-, mono-, granulo-, and thrombocytes were detected by fluorescence increase from R110 following intracellular substrate cleavage. Eukaryotic-AP do not cleave D-amino acids and hence NH2(D-Leu)2R110 substrate served as negative control. Specific substrate cleavage by AP is shown by complete inhibition of flFLuorescence generation following preincubation of cells with leucine-chloromethylketone inhibitor. R110 AP- and exopeptidase substrates are suitable indicators for coupled endopeptidase reactions due to their rapid cleavage and largely pH independent generation of intracellular fluorescence.

Amino Acids↗
PubMed1992

Prognostic value of flow cytometrically determined DNA-ploidy, intracellular pH and esterase activity of non-small cell lung carcinomas.

30 surgical specimens of patients with non-small cell lung carcinomas (NSCLC) were investigated. Significant increases of intracellular pH values in epithelial and inflammatory cells, in the percentage of dead epithelial and inflammatory cells and in the cell volume of vital inflammatory cells in cancerous lung tissue were encountered. Furthermore, decreases of the esterase activity of vital epithelial cells and of the percentage of free cell nuclei were observed. The DNA aneuploidy in 36.6% of the tumours was frequently associated with non-squamous cell carcinomas and stage II, III, IV tumours. Patients with DNA aneuploid tumours had a significantly shorter survival rate than those with DNA euploid tumours. Within the different tumour stages a similar tendency was observed which was, however, only significant in stage III tumour patients. Stage III tumours constitute therefore a heterogeneous entity with a worse prognosis for DNA aneuploid tumour patients. The intracellular pH values and esterase activity as well as the cell volume, the percentage of free cell nuclei and dead inflammatory or epithelial cells contained no significant prognostic information.

Adult↗
PubMed1990

Intracellular pH, esterase activity, and DNA measurements of human lung carcinomas by flow cytometry.

An important intention of flow cytometric investigations is to obtain biochemical and biophysical information about cells which is suitable for automated tumor diagnosis. In this study, the ploidy status, the intracellular pH value, the intracellular esterase activity, and the cell volume of vital cells and the DNA and cell volume of dead cells were measured in cancerous tissue and normal lung tissue of 30 patients by flow cytometry. The cell samples were simultaneously stained with the pH and esterase indicator dye 1.4-diacetoxy-2,3-dicyanobenzene (ADB) and propidium iodide (PI). The flow cytometric measurements were performed in three-parameter list mode. The data were evaluated on an AT-compatible personal computer with the DIAGNOS1 program system for automated diagnosis of flow cytometric list mode data. Significant differences were found between normal and malignant tissue in DNA ploidy, in the intracellular esterase activity, in the cell, volume and in the percentage of inflammatory cells and parameters of necrosis. DNA-aneuploidy was observed in 38% of the lung carcinomas. The simultaneous detection of DNA-aneuploidy and tumor-associated properties in a multifactorial analysis led to correct automatic tumor diagnosis in 85% of cases. DNA-aneuploidy was found at a significant higher frequency in advanced tumors. Adenocarcinomas displayed DNA-aneuploidy more often (80%) than squamous cell carcinomas (33%).

Adenocarcinoma↗
PubMed1984

New possibilities of cytostatic drug testing on patient tumor cells by flow cytometry.

A new assay for cytostatic drug testing is described which can be automated. Pleural effusions and ascites are cultured as such for one week. Cells of solid tumors are cultured in the patients own serum for the same time. The cells are then stained with the esterase and intracellular pH-indicator dye 1,4-diacetoxy-2,3-dicyano-benzene (ADB) to label vital cells. They are simultaneously stained with propidium iodide (PI) as an indicator for dead cells. Monosized fluorescent latex particles are added as concentration, volume and fluorescence standard. Inflammatory cells can be distinguished in the assay from tumor cells because of their small cell volume. The number of dead and surviving cells is counted by the flow cytometer and a therapeutic index is calculated as ratio between the surviving inflammatory to surviving tumor cells. An important feature of the assay is that the DNA-distribution of the dead cells (e.g. aneuploidy) as well as the functional state of the surviving tumor cells and inflammatory cells can be judged from intracellular esterase activity and intracellular pH.

Antineoplastic Agents↗