Anna-Maria Rosengren

Analysis of cysteinyldopas, dopa, dopamine, noradrenaline and adrenaline in serum and urine using high-performance liquid chromatography and electrochemical detection.

The catecholic amino acids, dopa, 2-S- and 5-S-cysteinyldopa, and 2,5-S,S-dicysteinyldopa were determined qualitatively in serum from patients with malignant melanoma by reversed-phase high-performance liquid chromatography, using electrochemical detection. In urine the catecholamines dopamine, noradrenaline and adrenaline were also determined qualitatively, as well as the above-mentioned compounds, in a single chromatographic run. The conditions were optimized by changing the pH of the mobile phase and by the addition of methanesulphonic acid. A comparison was made between the performance of four commercial reversed-phase packing materials containing chemically bonded octadecyl groups, using a standard mixture of catecholic amino acids. The influence of ionic strength, pH and amount of methanesulphonic acid on retention was investigated.

The quantitative determination of 5-S-cysteinyldopa and dopa in normal serum and in serum from patients with malignant melanoma by means of high-pressure liquid chromatography.

A method is described for quantitative determination of 5-S-cysteinyldopa and Dopa in serum involving high-pressure liquid chromatographic analysis (HPLC) and electrochemical detection. The chromatographic system allows estimation of injected amounts corresponding to 25 pg of 5-S-cysteinyldopa and Dopa. In normal subjects the mean serum 5-S-cysteinyldopa concentration was 2.8 ng/ml (range 0.4--12 ng/ml) and the mean serum Dopa 6.3 ng/ml (range 4--10 ng/ml). Patients with melanoma metastases showed increased serum concentrations of 5-S-cysteinyldopa.

Dopa and dopamine in the pigment of Substantia nigra.

Hydrolysate der Pigmentpartikel der Substantia nigra enthalten Dopa und Dopamin, jedoch kein Adrenalin, Noradrenalin oder Serotonin.

Dopamine and 5-hydroxytryptamine in the guinea-pig pancreas☆

Abstract Quantitative and qualitative investigations have demonstrated the presence of noradrenaline and 5-hydroxytryptamine in the guinea-pig pancreas. In addition, dopamine was found in the fetal and newborn guinea-pig pancreas in widely varying amounts that could reach high levels. Prenatally and for some time after birth, the pancreatic dopamine and 5-hydroxytryptamine are stored in morphologically similar cells located in the islets or scattered among the exocrine acini. There is strong evidence that both these amines are stored concomitantly in some of these cells.

Choline acetylase activity in the normal and denervated cat iris

Abstract Studies on the distribution of choline acetylase activity and catecholamines in the iris demonstrate that cholinergic and adrenergic nerves are distinctly separate entities. The presence of nerves possessing both cholinergic and adrenergic properties is most unlikely.

Dopa-decarboxylase and monoamine oxidase activities in a transplantable islet cell tumour of the golden hamster

In einem transplantierbaren Inselzelltumor des Goldhamsters, der neben 5-Hydroxytryptamin, Dopa und Dopamin eine bisher unidentifizierte, vermutlich monoaminähnliche Substanz enthält, wurde eine hohe Dopadecarboxylase- und Monoaminooxydaseaktivität gefunden. Nach Dopa-decarboxylasehemmung wurde eine starke Anhäufung von Dopa im Tumorgewebe beobachtet; dieser Befund weist auf eine schnelle Monoaminsynthese und einen schnellen Monoaminumsatz im Tumorgewebe hin.

Tyrosine hydroxylase activity in a transplantable islet cell tumour of golden hamster

In einem transplantierbaren Insel-zelltumor des Goldhamsters ist eine Tyrosinhydroxylase-Aktivität gefunden. Die hohe Aktivität der Enzyme zusammen mit einer starken Konzentration von Tyrosin deutet auf eine schnelle Synthese von Dopa in den Tumorzellen. Die Anwesenheit der Dopametaboliten DOPAC und HVA im Tumor wurde gezeigt.