Biomedical subjects

Per Sjöberg

Publications and source records attributed to Per Sjöberg.

3 recordsLinked to original sources

PubMed2006

ESI-MS detection of proposed reaction intermediates in the air-promoted and ligand-modulated oxidative Heck reaction.

Electrospray ionization mass spectrometry (ESI-MS) and subsequent MS/MS analyses were used to directly detect palladium-containing cationic reaction intermediates in a ligand controlled palladium(II)-catalyzed oxidative Heck arylation. All potential intermediates were observed as dmphen-ligated palladium(II) species, suggesting that the dmphen bidentate ligand is attached to the metal center during the entire catalytic cycle. The study supports previous mechanistic propositions and provides new information regarding the composition of aryl-containing Pd(II) complexes in an ongoing oxidative Heck reaction. In addition, sodium acetate was found to be a useful base alternative to previously used tertiary amines.

Air↗

PubMed2006

Urine profiling using capillary electrophoresis-mass spectrometry and multivariate data analysis.

This work presents the development of a general and fast method for metabolic profiling of urine, using capillary electrophoresis-electrospray ionisation mass spectrometry (CE-ESIMS) and multivariate data analysis (DA). Human urine samples collected before and after ingestion of paracetamol were analysed at acidic and basic CE conditions, using both positive and negative ESI-MS detection. Analysis of the entire resulting data set, with no prior knowledge of the target compounds, using pair-wise 'fuzzy' correlation and eigenvalue analysis enabled the samples to be discriminated between on the basis of blank urine and urine collected after drug intake. By generating two-dimensional loadings plots, it was also possible to identify the m/z values of the substances responsible for the differentiation between control and dosed samples.

Acetaminophen↗

PubMed1977

Pain relief during delivery by transcutaneous electrical nerve stimulation.

The degree of pain alleviation achieved by transcutaneous electrical nerve stimulation (TNS) during delivery has been evaluated. The usual technique of TNS was modified to suit the requirements of pain relief during delivery. Two pairs of electrodes were taped on the parturient's back at levels TH10--L1 and S2--S4. These segments correspond to the pathway of pain afferents into the spinal cord during the first and second stages, respectively. Stimulation was delivered by a two-channel generator producing biphasic pulses which were variable in frequency and amplitude. A low-intensity stimulation was given continuously and a high-intensity stimulation could be initiated by the parturient herself whenever pain increased. Stimulation was provided via the thoracic electrodes throughout the delivery, whereas sacral stimulation was added from the later part of the first stage. No complications with respect to mother or child have occurred. One hundred and forty-seven women have been treated, 65 (44%) of whom considered the pain relief by TNS to be good to very good, 65 (44%) experienced moderate effect, while 17 (12%) women considered that TNS was without effect. In view of the relatively good results and since no complications have occurred, we consider the method recommendable as a primary pain relieving measure to which conventional methods can be added according to need.

Anesthesia, Obstetrical↗