Biomedical subjects
Publications and source records attributed to C Hansson.
A previous finding of pronounced excretion of trichochromes in a patient with metastasizing melanoma and diffuse melanosis prompted this study on trichochromes in another patient with these two features. The patient now reported also excreted large amounts of trichochromes. Iit is suggested that diffuse melanosis in metastatic melanoma patients is due to deposition of trichochromes in the tissue.
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.
The excretion of the specific melanocytic metabolite 5-S-cysteinyldopa was studied in patients with psoriasis treated by 8-methoxypsoralen and UVA light. A pronounced increase was found after only 2 days treatment, although no increase in pigmentation could yet be observed. Peak values for urinary 5-S-cysteinyldopa were noted after 1 or 2 weeks treatment. Increase in pigmentation persisted after the excretion maxima for 5-S-cysteinyldopa.
Red cock feathers (Rhode Island) were found to contain dopa and cysteinyldopa, trichochromes B and C, and two unidentified trichochromes. Trichochromes E and F were not found. Previous findings of trichochromes E and F may be explained as artifacts.
Free dopa and 5-S-cysteinyldopa were extracted from two human melanomas. Subsequent hydrolysis of carefully washed melanoma tissue released dopa and 5-S-cysteinyldopa, indication the presence of these catechol amino acids in proteins. Cysteinyldopa-containing proteins may represent the antigens previously demonstrated in human melanomas.
The presence of trichochromes B and C in red human hair was confirmed with an analytical procedure which does not give rise to the formation of these compounds as artifacts. The trichochrome precursor 5-S-cysteinyldopa previously demonstrated in red guinea-pig hair was not detected in red human hair.
Decarboxytrichochromes B and C were isolated from a melanoma metastasis in a red-haired man, indicating the presence of trichochromes B and C in the tissue. Trichochromes E and F were not detected.
Two glucuronidated catechol have been identified in a transplantable islet cell tumour of the golden hamster, i.e. dopamine-4-O-glucuronide and 3-methoxytyramine-4-O-glucuronide. L-dopa is rapidly metabolized in the tumour to one or both of these glucuronides. Incubation of tumour homogenates in the presence of beta-glucuronidase shows that dopamine-4-O-glucuronide is present in the tumour in extremely high concentrations.
5-S-cysteinyldopa is metabolized by O-methylation on incubation with a liver extract and S-adenosyl methionine. O-methylated 5-S-cysteinyldopa isolated from melanoma urines by ion exchange and paper chromatography was identified by gas chromatography-mass spectrometry and NMR.
A clinical follow-up study has been carried out in order to study the periodontal health of orthodontically derotated teeth where the supra-alveolar fibers have been severed by an incision through the bottom of the marginal pocket to the border of the alveolar bone in order to reduce the tendency towards a posttreatment relapse. The material consisted of 30 rotated teeth treated orthodontically in 27 patients between the ages of 9 and 22 years. Following an average retention period of 8.3 months, the supra-alveolar fibers were severed down to the alveolar bone border. The control material consisted of untreated, banded contralateral teeth in the same jaw. The patients were examined for plaque, gingival health and depth of the marginal pockets. No significant difference in periodontal health could be found on comparison between, on the one hand, teeth treated with fibrotomy and, on the other hand, untreated teeth.
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Pseudomonas aeruginosa colonizes 20-30% of all venous leg ulcers. Hypothetically, P. aeraginosa could release proteases and cytotoxic substances in the environment of chronic ulcers, thus negatively affecting the wound-healing activity in this patient group. Here we show that P. aeruginosa isolates from leg ulcers exhibit a highly variable expression of the proteinases elastase and alkaline proteinase. We propose that bacterial phenotype should be taken into account in future studies on the clinical outcome of leg ulcers colonized by P. aeruginosa.
Haptens causing type I allergy have been shown to predominantly form lysine adducts in the carrier protein, while many haptens giving rise to type IV allergy preferentially form adducts with cysteine residues. Hexahydrophthalic anhydride derivatives are strong sensitizers capable of inducing allergic rhinitis, asthma and urticaria (type I allergy) and allergic contact dermatitis (type IV allergy). The ability of hexahydrophthalic anhydride (HHPA) to form adducts with nucleophilic amino acids and a model peptide in vitro is presented. Adduct formation was monitored by high-performance liquid chromatography with ultraviolet light/vis detection (LC-UV/vis) and high-performance liquid chromatography with mass spectrometric detection (LC/MS). The characterization was obtained by nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS and MS/MS). It was found that HHPA formed adducts with N(alpha)-acetylated lysine and cysteine and the non-acetylated alpha-amino group of proline and, to some extent, also with other nucleophilic amino acids. The adducts with lysine and proline were chemically stable. Addition of one HHPA to a model carrier peptide with all important nucleophilic amino acid residues showed N-terminal proline to be the major site of reaction. The addition of a second hapten gave a lysine adduct, but a minor cysteine adduct was also found. The cysteine-HHPA adducts were shown to be chemically unstable and participated in further reactions with lysine forming lysine-HHPA adducts. The results will be useful for understanding the formation of HHPA-protein adducts with the capability of being markers of exposure, and also to a deeper understanding of the chemical structures causing types I and IV allergy.
Ethylbutylthiourea (EBTU) is an accelerator used in the production of chloroprene (neoprene) rubber. EBTU occurs in a mixture with diethylthiourea (DETU) and dibutylthiourea (DBTU) in the accelerator. An analytical method originally developed for analysis of zinc dithiocarbamates in rubber has been used to analyse EBTU, DETU and DBTU in a knee brace responsible for an allergic contact dermatitis in a gardener suffering from arthrosis. EBTU was isolated and gave positive reactions when tested as a pure compound. The test reaction was accompanied by positive reactions to DETU and DBTU.
The type of chemical reaction between hapten and carrier protein in the formation of a complete antigen in vivo giving rise to an allergic contact dermatitis (ACD, type IV allergy) is essentially unknown. About 4000 low-molecular organic compounds are known to have allergenic properties. alpha,beta-Unsaturated carbonyl structures are frequently present among these compounds. Haptens giving rise to antibody formation and type I allergy have been shown to add predominantly to lysine in the carrier protein. In this paper, the reactivity of activated type IV haptens to a model peptide is reported. Essentially all amino acids with nucleophilic properties were present in the model peptide. Investigation of the relative reactivities of the amino acid residues to activated haptens under biomimetic conditions is performed in order to determine the proportions between the adducts of the different amino acid moieties. In all cases, the electrophilic alpha,beta-unsaturated haptens were found to be added to the cysteine residue and no lysine adduct was recorded. Nuclear magnetic resonance (NMR) spectroscopy was used to exclude steric hindrance of any amino acid residue in the addition reaction. The hapten-modified peptides were isolated and characterized by NMR and mass spectrometry.
Allergic contact dermatitis from esters of fumaric acid or esters of maleic acid is rare. The case of a chemist with allergic reactions to esters both of fumaric acid and of maleic acid is presented. Extremely high sensitivity of the patient to diethyl fumarate was noted. The formation of identical complete antigens from esters of these two cis-trans isomeric acids may be an explanation of the patient's double allergy. This is discussed from a stereochemical point of view. These stereochemical considerations point to a general mechanism where cis-trans isomeric alpha,beta-unsaturated carbonyl compounds are converted into the same complete antigen.