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Biomedical subjects

A Petersen

Publications and source records attributed to A Petersen.

At least 127 records · Page 7Linked to original sources
PubMed1988

Cytophilic and cytotoxic properties of human eosinophil peroxidase plus major basic protein.

The cytophilic and cytotoxic properties of an acetate-buffered solution of human eosinophil peroxidase (EPO) plus major basic protein (MBP) were studied to determine the cytotoxic potential of localized eosinophil degranulation in human tissues. When incubated with EPO + MBP for 5 minutes, viable cells of six unrelated types (Sp 2/0; HeLa; human gastric adenocarcinoma; acute lymphocytic leukemia; IM-9; benign lymphoid hyperplasia) developed varying degrees of cytochemically detectable deposits of EPO on the cell membranes. A single-step propidium iodide exclusion assay was then used to show that EPO + MBP in the absence of hydrogen peroxide is substantially cytotoxic only to the acute lymphocytic leukemia and IM-9 cells. In the presence of 0.003% hydrogen peroxide, EPO + MBP was cytotoxic to five types of cells. It is concluded that human EPO in the presence of MBP has an affinity for the membrane of diverse cell types. The toxicity of EPO + MBP is markedly enhanced by the presence of hydrogen peroxide.

Blood Proteins↗
PubMed1987

31P NMR measurements of intracellular pH in erythrocytes: direct comparison with measurements using freeze-thaw and investigation into the influence of ionic strength and Mg2+.

The pH-dependent chemical shift behavior in 31P NMR spectroscopy of inorganic phosphate (Pi) and methylphosphonic acid (MeP) in solutions of various composition at 37 degrees C are presented. An ionic strength dependent lowering of the pKa values of both Pi and MeP is observed. 3 mmol/liter Mg2+ did not affect the pH-dependent chemical shift behavior of Pi and MeP in solutions containing 135 mmol/liter KCl and 5 mmol/liter NaCl. This finding was reinforced by adding 5 mmol/liter 2,3-diphosphoglycerate (2,3-DPG) and 1.5 mmol/liter ATP to solutions with 3 mmol/liter Mg2+. The presence of these Mg2+-binding substances had no detectable effect on the chemical shift of Pi and MeP at various pH values. The pH dependence of the chemical shift of MeP, Pi, and 2,3-DPG in oxygenated erythrolysates was compared to protein free model solutions. No significant differences could be detected for MeP and Pi whereas there was a change in the chemical shift of about 0.1-0.2 ppm for both phosphates in 2,3-DPG. Finally intracellular pH estimated by 31P NMR were compared to pH measured by electrode in freeze-thawed hemolysates. At an extracellular pH of 7.341 +/- 0.045 (SD) (n = 6) the intracellular pH was 7.160 +/- 0.014 (SD) by the freeze-thaw procedure and 7.213 +/- 0.027 (SD), 7.172 +/- 0.029 (SD), and 7.152 +/- 0.033 (SD) estimated by the chemical shift of MeP, and 3-phosphorus and 2-phosphorus of 2,3-DPG, respectively.

Erythrocytes↗
PubMed1987

31P NMR measurements of intracellular pH and 2,3-diphosphoglycerate in erythrocytes.

31P nuclear magnetic resonance (NMR) spectroscopic determinations of 2,3-diphosphoglycerate (2,3-DPG) concentrations in erythrocytes have been compared with values obtained by an enzymatic assay. It was found that the mean difference over a concentration range from 2 to 20 mmol 2,3-DPG/1 red blood cells (RBC) was 0.18 +/- 0.39 (SEM) mmol/l RBC (n = 10). 31P NMR spectroscopy was further tested by simultaneous measurements of 2,3-DPG and intracellular pH under conditions where the concentration of 2,3-DPG was varied. Thereby a linear relation between the pH gradient (delta pH) over the erythrocyte membrane and 2,3-DPG concentrations was found. The data fit a Donnan equilibrium model for the pH difference over the erythrocyte membrane. We conclude that 31P NMR spectroscopy is a sensitive and accurate method that makes possible simultaneous and non-invasive measurements of intracellular pH and 2,3-DPG.

2,3-Diphosphoglycerate↗
PubMed1986

Identification of phosphorylethanolamine in 31P-NMR spectra of human peripheral blood lymphocytes.

The 31P-NMR spectrum of intact human peripheral blood lymphocytes contains a large unidentified peak in the phosphomonoester region. The pH dependency of the 31P-NMR chemical shift of this peak in perchloric acid extracts of peripheral blood lymphocytes was recorded. It was compared to the pH dependency of the chemical shift of phosphorylethanolamine, phosphorylcholine, and ribose 5-phosphate in model solutions. An excellent agreement was found between the behavior of phosphorylethanolamine and the unidentified peak. To further substantiate this assignment phosphorylethanolamine was added to extracts and the pH titrations were repeated. The added phosphorylethanolamine gave exactly the same chemical shift as the unidentified peak and no difference was observed with pH titrations. The concentration of phosphorylethanolamine in human peripheral blood lymphocytes was estimated by 31P NMR to be 2.4 mumol/10(9) cells (range 0.9-4.3/10(9) cells, n = 4).

Animals↗
PubMed1984

Clinical and cytogenetic studies in a large (4;8) translocation family with pre- and postnatal Wolf syndrome.

Partial deletion of 4p (Wolf syndrome) is reported in two cases resulting from paternal balanced t(4;8)(p163;p231). One of them was diagnosed prenatally and aborted. Autopsy revealed dysmorphic face, and malformed heart and kidneys. The other case, the mentally retarded sister, had no clinical signs of internal malformations, only slightly dysmorphic appearance. We concluded that loss of the terminal segment of 4p(4p163) seems sufficient to produce the clinical entity of Wolf syndrome, and partial trisomy of the short arm of chromosome 8 did not mask the 4p- phenotype. Segregation analysis showed risk figures of about 15% for a malformed child comparable to previously given figures concerning the outcome of autosomal reciprocal translocations.

Abnormalities, Multiple↗