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Biomedical subjects

H Karlsson

Publications and source records attributed to H Karlsson.

At least 109 records · Page 6Linked to original sources
PubMed1987

The mono- and difucosyl blood group B glycosphingolipids of rat large intestine differ in type of core saccharide.

Two blood group B-active glycosphingolipids were isolated from rat large intestine and characterized by mass spectrometry, proton NMR spectroscopy and methylation analysis. The following structures were concluded: Gal alpha 1----3(Fuc alpha 1----2)Gal beta 1----3GlcNAc beta 1----3Gal beta 1----4Glc beta 1----1Cer and Gal alpha 1----3(Fuc alpha 1----2)Gal beta 1----4(Fuc alpha 1----3)GlcNAc beta 1----3Gal beta 1----4Glc beta 1----1Cer. The two glycolipids thus differ in their core saccharides (type 1 and type 2 chain, respectively) and therefore must have different pathways for biosynthesis.

ABO Blood-Group System↗
PubMed1987

Application of a simple methylation procedure for the analyses of glycosphingolipids.

Acid and neutral glycosphingolipids (0.01-1 mumol) were completely methylated in high yields and with little formation of by-products in 10 min at room temperature, using methyl sulphoxide, methyl iodide, and powdered NaOH. Re-methylation of methylated and LiAlH4-reduced gangliosides gave a new derivative that was useful for the analysis of gangliosides by mass spectrometry.

Animals↗
PubMed1987

Recurrent factitious hypercalcemia.

Severe hypercalcemia recurred three times during an observation period of 15 years in a woman with anorexia nervosa. The patient displayed a factitious cheese-alkalosis syndrome similar to the iatrogenic milk-alkali syndrome.

Adult↗
PubMed1986

Cell surface markers for diagnosis of central nervous system involvement in lymphoproliferative diseases.

To diagnose lymphoproliferative central nervous system (CNS) involvement we have used monoclonal antibodies in an immunocytochemical method for differentiation of cells in cerebrospinal fluid (CSF) and peripheral blood. The cell distribution in 9 patients with B-cell lymphoma and 7 patients with chronic lymphatic leukemia was compared to that in a group of patients with aseptic meningitis. Most patients with neoplastic CNS involvement showed a high proportion of CSF B cells (OKB2+ and/or OKB7+) and a concurrently low proportion of CSF T cells (anti-Leu 1+). Proliferating cells expressing transferrin receptor (OKT9 labeled) were increased in the CSF of 2 patients with neoplastic CNS involvement. In 2 patients with infectious CNS complications, the cell distribution in CSF did not differ from that in patients with aseptic meningitis. Patients with leukemia who had no CNS symptoms, and also 1 patient with meningitis and blood-brain barrier damage, showed a normal cell distribution in CSF despite high B-cell numbers in the peripheral blood. This indicates a selective passage of leukocytes into the CNS and/or local proliferation.

Adult↗
PubMed1986

GalNAc beta 1----3 terminated glycosphingolipids of human erythrocytes.

Nonacid glycosphingolipids with 4 to 10 sugar residues isolated from pooled erythrocytes of blood group O donors have been efficiently separated as peracetylated derivatives on silicic acid. This procedure enabled a quantitative estimate of individual compounds and also revealed several GalNAc beta 1----3 terminated structures. The structural characterization of these glycolipids with 1H-NMR spectroscopy, direct inlet mass spectrometry, gas chromatography, and gas chromatography-mass spectrometry identified the compounds as GalNAc beta 1----3Gal alpha 1----4Gal beta 1----4Glc beta 1----1-N-acetyl sphingosine and GalNAc beta 1----3Gal alpha 1----4Gal beta 1----4Glc beta 1----1-N-acetyl phytosphingosine, GalNAc beta 1----3GalNAc beta 1----3Gal alpha 1----4Gal beta 1----4Glc beta 1----1 ceramide, and GalNAc beta 1----3Gal beta 1----4GlcNAc beta 1----3Gal beta 1----4Glc beta 1----1 ceramide.

Acetylation↗
PubMed1983

Simultaneous gas chromatographic analysis of drugs of abuse on two fused-silica columns of different polarities.

A convenient and rapid gas chromatographic method for analysis of drugs of abuse has been developed. By installing two differently coated columns in a common split-splitless injector and connecting the column ends to a nitrogen-phosphorus detector and a flame ionization detector, considerable and accurate chromatographic information could be obtained from a single run. Quantitative analyses of amphetamine and some other drugs have been performed with the same instrumental set-up. Calibration graphs were evaluated and showed linearity in the concentration range chosen (0.5-10 mg/ml). By using an auto-sampler in combination with a BASIC program, both types of analyses can be performed routinely.

Amphetamine↗
PubMed1981

Methyl mercury binding substances from the brain of experimentally exposed squirrel monkeys (Saimiri sciureus).

Squirrel monkeys were given a single subtoxic dose of 203Hg-labelled methyl mercuric hydroxide. After three weeks the brains were dissected out, homogenized and separated into particulate and soluble fractions by ultracentrifugation. The soluble fractions were further separated into high molecular weight and low molecular weight components by ultrafiltration. The major part (75%) of the radioactivity was associated with the particulate fraction while high molecular weight compounds in the soluble fraction accounted for 16%. The remainder (9%) was bound to glutathione.

Animals↗
PubMed1978

Quantitative studies on competitive ligand binding to bovine serum albumin by use of the spin label 5-doxyl dodecanoic acid.

The binding of the spin label 5-doxyl dodecanoic acid to bovine serum albumin in phosphate buffer at pH 7.4 was studied by electron spin resonance spectroscopy. Free label and label bound to serum albumin could be quantitatively measured and evaluated from the superposition spectra of these two species with no previous separation. The efficiency relative to the spin label as competitors for binding to serum albumin was studied with salicylic acid and some fatty acids of medium length. The results were represented both by the stoichiometric model involving equilibrium constants Ki, by binding isotherms constructed from the Ki values, and by a purely graphical representation of the experimental data points without connection with any special binding model.

Binding, Competitive↗
PubMed1975

Time courses of pulmonary gas exchange and heart rate changes in supine exercise.

The time courses of ventilation (VE), O2 uptake (VO2), CO2 elimination (VCO2), respiratory exchange ratio (R), end-tidal PO2 and PCO2 and heart rate (HR) were studied in seven subjects performing light dynamic leg exercise in the supine position. Individual and group mean time courses in response to step changes in work load were computed and displayed graphically. A computer-based method was also used to fit mono- or bi-exponential mathematical functions to the recorded responses. The over-all rate of HR change in response to the transition from 0-load pedalling to exercise (on-response) was faster (mean response time, MRT = 31 s) than the corresponding VO2 response (MRT = 45 s) while VE responded considerably slower (MRT = 86 s). During the reverse transition (off-response), VO2 and VE changed with the same rate as in the on-response, while the HR-change was slower than during the on-response (MRT = 50 s). During the initial 15-sec period, VO2 changed only slightly, which contrasts to previous results in the sitting position, where 50% of the final change in VO2 has been reported to occur within the first 15-sec period, and where changes in blood distribution and stroke volume are known to be more pronounced than in the supine position. Our results emphasize the importance of central circulatory changes for the time course of VO2 at the start and end of exercise.

Adult↗
PubMedDate not supplied

Identification of two-dimensional gel electrophoresis resolved yeast proteins by matrix-assisted laser desorption ionization mass spectrometry.

Protein extract from yeast cells growing exponentially in saline medium was separated by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), with the separation in the first dimension on a wide range immobilized pH (3-10) gradient. From one preparative 2-D gel a number of previously identified proteins were used as test material for our initial matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) efforts on large scale rapid protein spot identification. Sample preparation via in-gel trypsin digestion was slightly modified to be compatible to MS analysis, and via this modified procedure MS generated peptide mass profiles could, in most cases with good precision, identify the protein in question. Preferential ionization was tested on a yeast aldehyde dehydrogenase (ALD7), and it was shown that the ionization of some peptides was clearly suppressed by the presence of others. Roughly 50% of the observed peptide masses was found by the search routines in the database, and the mass measurement accuracy of the peptides was within 0.5 Da. Silver-stained gels could be used with good results for the generation of peptides to be analyzed by MALDI-MS. For one of the 2-D resolved proteins, glycerol 3-phosphatase (GPP1), the post-source decay (PSD) spectrum proved crucial in identification.

Amino Acid Sequence↗
PubMedDate not supplied

The use of 13C NMR spectroscopy in forensic drug analysis.

13C NMR spectroscopy has been used for analysis of fourteen compounds which, according to Swedish laws are defined as narcotic drugs or are substances often found in combination with these drugs. The carbon-13 NMR method seems to be well suited for analysis of complex forensic drug mixtures because no preliminary separation of components is required.

Amphetamine↗
PubMedDate not supplied

Tricyclic antidepressants induce apoptosis in human T lymphocytes.

Apoptosis is a form of programmed cell death that is involved in cell turnover. In the present study we show that the tricyclic antidepressants (TCAS) imipramine, clomipramine and citalopram induce apoptosis in human peripheral lymphocytes. Lymphocytes were incubated with these three drugs for up to 48 h. Apoptosis was characterized by typical nucleosomal DNA fragmentation on agarose gel, as well as quantitated using 4'-6-diamidino-2-phenylindole (DAPI) staining and 3'-OH end-labeling of fragmented DNA at the single cell level. Apoptosis induced by TCAs was shown to be dose-dependent and could be detected after a 24 h incubation. The optimal concentrations of the three TCAs found to induce apoptosis were 50 microM imipramine, 20 microM clomipramine and 180 microM citalopram. Furthermore, immunofluorescence and three-color flow cytometry were used to identify the phenotype of apoptotic cells. TCA-induced apoptosis was shown to involve exclusively T-lymphocytes. Cytotoxic T-lymphocytes were more prone to undergo apoptosis than were T-helper cells. In conclusion, the present investigation clearly demonstrates that TCAs exert cell biological effects upon human T-lymphocytes. Further studies are required to determine the possible clinical relevance of these findings.

Adult↗