Biomedical subjects

G Wennersten

Publications and source records attributed to G Wennersten.

54 records · Page 3Linked to original sources

PubMed1979

Membrane damage caused by 8-MOP and UVA-treatment of cultivated cells.

Treatment of red blood cells with a combination of 8-MOP and UVA did not cause any significant hemolysis under the experimental conditions used, and the deuterium test for identification of singlet oxygen mediated reactions was negative. However, similar experiments performed on in vitro cultivated human glia cells caused conspicuous surface membrane alterations, as revealed by scanning electron microscopy. The alterations were seen at higher concentration levels than was expected and might be secondary to earlier appearing intracellular events seen at lower concentrations. The clinical significance of membrane alterations for the results obtained with PUVA therapy require further investigation.

Cell Line↗

PubMed1979

Mucinosis follicularis provoked by light exposure.

The present paper reports a study on a case of follicular mucinosis exacerbated by sunlight exposure. Provocation with standardized light testing was carried out on both normally pigmented skin and on areas of hypopigmentation representing a residual state after earlier skin lesions but without any signs of active mucinosis follicularis. Typical clinical and histologically verified lesions were provoked by the light test procedure, best seen in hypopigmented areas but with similar changes in normally pigmented skin. Characteristic findings developed gradually, assuming an appearance identical with that of the observed spontaneously elicited lesions after 3--4 weeks. Treatment with carotenoids periodically over several years has provided a proper light protective effect, as only minimal lesions have been noted during these periods, compared with extensive changes during similar periods without treatment.

Adult↗

PubMed1979

Photodynamic reactions induced by compounds derived from lichens.

Contact dermatitis from lichens is now well documented but the possible influence of exposure to sunlight is less clear. Positive reactions on photopatch testing has recently been described, but whether this represented an unspecific exacerbation or a true photoallergic response was difficult to evaluate. In this study 13 different substances derived from lichens commonly found in nature were investigated with regard to their capacity to induce photo-oxidative membrane damage, as revealed by the photohemolysis technique. It was found that the earlier suggested ability to induce photosensitization could be confirmed for several of the lichen compounds investigated. It was also shown that singlet state excited oxygen may participate to some degree in some of these reactions.

Adult↗

PubMed1978

Photoprotection of the eye in PUVA therapy.

Explore the source record for details and available documents.

Eyeglasses↗

PubMed1978

Cellular aspects of phototoxic reactions induced by kynurenic acid. II. Fine structural analysis and cytochemistry on cultivated cells.

A recent report described the establishment of an experimental model for studying photo-oxidative damage inflicted by kynurenic acid on cultivated cells. Preliminary findings by scanning electron microscopy (SEM) were reported. For the present paper supplementary SEM studies were performed, and it was found that maximum cell damage appears 2 to 4 hours post irradiation. With low concentrations of kynurenic acid and brief UVA exposure, repair mechanisms seem to occur. Damage in the form of cellular swelling and plasma membrane alterations is most easily recognized by SEM, which is far more sensitive than ordinary light microscopy. Transmission electron microscopy (TEM) reveals morphologic alterations, consisting of an enhanced formation of endocytotic vacuoles from the plasma membranes, swelling with disruptions of the cell sap continuity, mitochondrial swelling, dilatation of the endoplasmic net, and vesiculation of some of the microvilli. Lysosomal damage, which was not seen until very late post irradiation and only for high concentrations of kynurenic acid and long-term UVA exposure, seems to be a secondary phenomenon. This hypothesis is further supported by the cytochemical analysis. The primary event thus seems to affect the plasma membrane level and originate in the binding of kynurenic acid to the plasma membrane on which subsequent UVA irradiation inflicts secondary intracellular alterations due to increased permeability and swelling.

Cells, Cultured↗

PubMed1977

Light sensitivity and chromium dermatitis.

In 25 consecutive cases of chromium contact allergy we have made four parallel serial dilution tests and irradiated three of the test rows, two with solar-spectrum-like radiation from a 150 W Xenon lamp (4/5 MED and 4 MED) and one row with long-wave ultraviolet radiation (blacklight) alone. Comparing an unirradiated row (control) and the row irradiated with 4/5 MED, the reactions were significantly more intense in 48% of the cases, i.e. the patients reacted at lower chromium concentrations. In a corresponding comparison with 4 MED a significantly more intense reaction was obtained in 36% of the cases, whereas blackslight showed no significant difference compared with the control row. The most intense reactions were obtained in the cases which were anamnestically photosensitive and had low MED values.

Chromium↗

PubMed1977

Treatment of porphyria cutanea tarda with chloroquine and phlebotomy.

Treatment of porphyria cutanea tarda (PCT) with chloroquine risks serious side-effects so we have combined it with phlebotomy. One to four venesections were performed before the administration of chloroquine in 10 PCT patients. Equally high excretion of urinary porphyrins was achieved but the side-effects were reduced. Chloroquine may be used as a provocative diagnostic test for patients with a questionably latent PCT but this is safe if phlebotomy is performed beforehand.

Adult↗

PubMed1977

Cellular aspects of phototoxic reactions induced by kynurenic acid. I. Establishment of an experimental model utilizing in vitro cultivated cells.

Kynurenic acid is an endogenously occurring tryptophan metabolite, which, under certain conditions, may accumulate in human tissues. In earlier work kynurenic acid showed a pronounced photohemolytic capacity, and conclusive evidence has been presented that the reaction is mediated by singlet oxygen. The aim of the present study was to gain further information about the cellular mechanisms involved in the photo-oxidative damage induced by kynurenic acid. This paper is mainly concerned with the establishment of a proper experimental model utilizing in vitro cultivated cells, but basal cytotoxic effects revealed by the use of cell growth curves, and light- and scanning electron microscopic examinations are also described.

Cell Line↗

PubMed1977

Photodynamic aspects of some metal complexes.

The potential phototoxic capacity of some metal compounds of clinical significance in dermatology has been investigated by means of the photohemolysis technique. No photosensitized hemolysis of erythrocytes was observed with the chromium, nickel, copper and cobalt compounds studied. On the contrary, nickel and cobalt compounds proved to be efficient in quenching singlet oxygen mediated photo-oxidative membrane damage of red blood cells. Cadmium compounds showed a pronounced photohemolytic activity and the reaction was oxygen dependent. The deuterium test for singlet oxygen showed a significant increase in photohemolytic efficiency. The addition of histidine, a known quencher of singlet oxygen, resulted in a significant inhibition of the photohemolysis. Pronounced photo-oxidative damage to plasma membranes was also observed in vitro cultivated cells by means of scanning electron microscopy.

Chromium↗

PubMed1975