Elisabeth Bohnert

Effects of 8-Methoxypsoralen (8-MOP) and UVA on human lymphocytes

SummaryPeripheral lymphocytes of 37 psoriatic patients are tested before and under PUVA treatment using as parameter the non specific stimulation effect of HgCl2 (10 µg/ml) in culture, measuring the3H-thymidine incorporation after the last 16 h of a 5-days culture. Oral 8-MOP in therapeutic doses is decreasing the lymphocyte stimulation as well as 8-MOP together with UVA irradiation during the first week of treatment. After 1 week, the stimulation is, on the contrary, significantly enhanced after irradiation. Lymphocytes isolated by centrifugation over Lymphoprep are submitted to PUVA conditions in petri dishes (Hanks solution 8-MOP 1 µg/ml, irradiation with 350 nm, 93-372 mJ/cm2). The total cell number, the E-rosette formation (as marker for T-Lymphocytes) and the EAC-rosette formation (as marker for B-Lymphocytes) are determined. PUVA conditions have an energy dependent decreasing effect on the cell number, while the T- and B-cell proportions remain constant. UVA irradiation alone has such an effect only with high energies. 8-MOP without UVA has no significant influence on the cell number.ZusammenfassungDie unspezifische Stimulierung der Blutlymphocyten von 37 Psoriatikern durch HgCl2 in der Leukocytenkultur wurde vor und während der PUVA-Therapie gemessen (Maßzahl: Incorporation von3H-Thymidin, Kulturdauer 120 h, Konzentration 10 µg/ml). Oral verabreichtes 8-MOP in therapeutischer Dosis vermindert in der ersten Therapiewoche die Lymphocyten-Stimulierung ebenso wie 8-MOP plus UVA-Bestrahlung. Nach einer Woche jedoch wird die Lymphocyten-Stimulierbarkeit durch UVA Bestrahlung signifikant erhöht. Über Lymphoprep isolierte Lymphocyten wurden in vitro PUVA-Bedingungen ausgesetzt (Hanks solution 8-MOP 1 µg/ml, Bestrahlung mit 350 nm und Energien zwischen 93-372 mJ/ml). Bestimmt wurden die Gesamtzellzahl, der Prozentsatz der E-Rosetten (als Maßzahl für T-Lymphocyten) und der EAC-Rosetten (als Maßzahl für B-Lymphocyten). PUVA-Bedingungen senken energieabhängig die Zellzahl, während der prozentuale Anteil der T- und B-Lymphocyten konstant bleibt. UVA allein hat diesen Effekt nur bei sehr hohen Energien, 8-MOP allein hat gar keine Wirkung.

Dysplastic Nevus Syndrome: Ultraviolet Hypermutability Confirmed in vitro by Elevated Sister Chromatid Exchanges

The dysplastic nevus syndrome (DNS) is a clinical and genetic entity in which affected individuals have increased numbers of dysplastic nevi and a markedly increased risk of developing one or more cutaneous melanomas. Sister chromatid exchanges (SCE) are one of the cytogenetic end points that are positively correlated with the mutation rate and may therefore be used to estimate the spontaneous and the UV-induced mutagenesis in cultured and stored fibroblasts. SCE were presented and stained according to the Hoechst-Giemsa method. The normal control fibroblasts showed 9.48 +/- 1.74 SCE per metaphase (n = 23) with an UV-C-induced increase (delta SCE) of 1.61 +/- 0.53 SCE per mJ/cm2 in the range of 0-5 mJ/cm2. Fibroblasts from DNS patients with melanoma (n = 12) showed normal values of spontaneous SCE but a significant increase (p = 0.01) of 2.43 +/- 0.68 SCE per mJ/cm2. As in xeroderma pigmentosum, UV-C-induced delta SCE appears as a valuable tool for measuring the individual hypermutability in DNS. delta SCE indicates the increased susceptibility to UV-induced somatic mutations and may be etiologically related to the increased melanoma incidence in DNS.

Light-induced skin cancer and prolonged UV-erythema

SummaryThe individual minimal erythema dose (MED) and the persistence of a marked erythema (8 MED) was monitored over 3 weeks (300 nm ± 10 nm) in 4 groups: White students with fair complexion compared with students of homogenous pigmentation as well as skin carcinoma patients compared with a control group of the same age, i.e., older than 50 years.The MED of the 4 groups gives no significant differences, while the skin carcinoma group shows in 80% a prolonged erythema persistence (control group only 28%). This phenomenon does not seem to correlate with the skin type and may be useful in identifying high-risk patients prone to light-induced skin cancer.ZusammenfassungDie individuelle minimale Erythemdosis (MED) und die Persistenz eines deutlichen Erythemes (8 MED) wurde während 3 Wochen (300 nm±10 nm) bei folgenden 4 Gruppen untersucht: Studenten mit heller Komplexion wurden verglichen mit solchen einer homogenen braunen Pigmentierung. Patienten mit Lichtcarcinomen über 50 Jahre alt wurden mit einer Kontrollgruppe verglichen, die keine Carcinome tragen.Die MED der 4 Gruppen zeigt keine signifikanten Unterschiede. Die Gruppe mit Lichtcarcinomen zeigt in 80% eine überlange Persistenz des Erythems (Kontrollgruppe nur 28%). Dieses Phänomen ist nicht mit dem Hauttyp korreliert und könnte zur prospektiven Identifizierung von Risikopatienten für Lichtcarcinome Anwendung finden.

Nephrotic syndrome, hypertension, and adrenal failure in atypical Cockayne syndrome

This report describes a boy with an atypical severe form of Cockayne syndrome type II manifesting in infancy. He developed nephrotic syndrome at the age of 4.7 years and a hypertensive crisis with hemiparesis at 5.4 years. Renal biopsy revealed focal segmental glomerulosclerosis, which was confirmed at autopsy. Adrenocortical failure was also present. The course was characterized by frequent infections and an episode of myocarditis. The boy died at the age of 6.0 years after rapid neurological deterioration accompanied by renal insufficiency. Autopsy disclosed cerebral leukodystrophy compatible with Cockayne syndrome.

Risk factors of the cutaneous melanoma phenotype

SummaryOf 20 melanoma patients 85% show a prolonged erythema persistence after a marked test erythema of 8 MED with 300 nm±10 nm (control group only 34%).This phenomenon does not correlate with the skin type and is useful in identifying high-risk patients prone to melanoma and light-induced skin cancer (92%).The spontaneous and the UV-C-induced number of sister chromatid exchanges (SCE) per metaphase was significantly higher in peripheral leukocytes of melanoma patients than in normal controls. The attempt was made to establish a “risk-spectrum” of cutaneous melanoma phenotype.ZusammenfassungVon 20 Melanompatienten zeigen 85% eine überlange Persistenz eines deutlichen Erythems durch 8 MED mit 300 nm±10 nm (Kontrollgruppe nur 34%). Dieses Phänomen ist nicht mit den Hauttyp korreliert und kann zur prospektiven Identifizierung von Risikopatienten für Melanome und Lichtkarzinome (92%) Anwendung finden.Die Zahl spontaner und UV-C-induzierter „sister chromatid exchanges” (SCE) pro Metaphase ist in peripheren Leukozyten von Melanompatienten signifikant höher als bei der Kontrolle. Es wird der Versuch formuliert, ein „Risikospektrum” des Melanom-Phänotyps abzustecken.

Effects of UV-C and of 8-MOP + UV-A on the T- and B-Population of human lymphocytes in vitro

SummaryThe transformation of UV-C irradiated leucocytes and lymphocytes by the mitogens Con A, PHA and PWM is measured by the3H-Tdr. incorporation after 72 h incubation. Furthermore T-and B-cells are determined by the method of rosette formation. A clear inhibition of the cell activity is seen after irradiation of leucocytes with 450 mJ/cm2 and of a lymphocyte suspension with 5–10 mJ/cm2. There are no significant differences between the effects of the various mitogens. The number of T-cells decreases proportionality to the various intensity, the number of B-cells remain constant. Irradiation with UV-A + 8-MOP cause, equaly for all mitogens, a dosis dependent inhibition of thymidine incorporation.ZusammenfassungAn UV-C bestrahlten Leukocyten und Lymphocyten werden im LTT mit den Mitogenen Con A, PHA und PWM nach 3 Tagen Kultivierung die3H-Thymidineinbauraten in die überlebenden Zellen gemessen. T- und B-Zellen werden anhand der Bildung von E- und EAC-Rosetten bestimmt. Bei Leukocyten ist mit 450 mJ/cm2, bei isolierten Lymphocyten schon mit 5–10 mJ/cm2 eine deutliche Hemmung der Zellaktivität festzustellen. Es ergeben sich keine statistisch signifikanten Unterschiede in der Wirkung der verschiedenen Mitogene. Bei bestrahlten Lymphocyten nimmt die Zahl der T-Zellen proportional zur Bestrahlungsintensität ab, die Zahl der B-Zellen bleibt weitgehend konstant. UV-A-Bestrahlung von Lymphocyten mit 8-MOP bewirkt im LTT, gleichmäßig für alle Mitogene, eine dosisabhängige Hemmung des Thymidineinbaus.The transformation of UV-C irradiated leucocytes and lymphocytes by the mitogens Con A, PHA and PWM is measured by the 3H-Tdr. incorporation after 72 h incubation. Furthermore T- and B-cells are determined by the method of rosette formation. A clear inhibition of the cell activity is seen after irradiation of leucocytes with 450 mJ/cm(2) and of a lymphocyte suspension with 5-10 mJ/cm(2). There are no significant differences between the effects of the various mitogens. The number of T-cells decreases proportionality to the various intensity, the number of B-cells remain constant. Irradiation with UV-A + 8-MOP cause, equally for all mitogens, a dosis dependent inhibition of thymidine incorporation.

Dysplastic Nevus Syndrome: Intrafamilial Identification of Carriers by Cytogenetics

Seven members of a family with dysplastic nevus syndrome (DNS) were examined clinically; skin biopsies of unaffected skin from 6 were taken. Biopsy-derived cultivated fibroblasts were examined by cytogenetic methods, i.e. by measuring the spontaneous and the UVB- and UVC-driven increase in sister chromatid exchange (SCE). A male patient with malignant melanoma, his son and his nephew, both with multiple dysplastic nevi, showed a distinctive elevation of UV-induced SCE, whereas the other, unaffected members of the family showed normal values. These results give evidence that in siblings with DNS the affected members can be identified not only on clinicopathological grounds but also by UV-induced elevated SCE at the cytogenetic level.

Elevated sister chromatid exchange (SCE) rate in patients with sun-induced skin tumors.

High-risk persons prone to actinic keratosis and sun-induced malignancies of the skin are characterized by fair complexion with light hair and blue eyes. They have freckles, suffer easily from sunburn, and tan poorly. Non-melanoma skin tumor patients show the persistence of a marked erythema [2, 7] and a reduced UVinduced DNA repair synthesis in peripheral leukocytes [1, 4] as well as in cultured fibroblasts [6]. Recent investigations have evidenced that melanoma patients (irrespective of the melanoma type) behave differently; they show a prolonged UV erythema [3] without a significant reduction of the DNA repair synthesis in leukocytes [5]. The following study was done to investigate whether or not the spontaneous SCE and the UVC-induced increase of SCE in peripheral leukocytes is an additional criterion of risk. SCE with and without UVC irradiation was studied in vitro in peripheral leukocytes of 21 patients with sun-induced, non-melanoma skin tumors and in 21 healthy controls of the same age. The BrdU-Hoechst-Giemsa method used was already described in detail previously [3, 8]. SCE was observed at a magnification of x 1,000, oil immersion objective, and counted per metaphase. All exchange points, including those in the centromere, were estimated as SCE. The spontaneous SCE and the UVC-induced increase of SCE (Fig. 1) were counted in peripheral leukocytes of 21 patients with multiple sun-induced nonmelanoma tumors of the skin (actinic keratoses, basal cell and prickle cell carcinomatas) and compared with a control group of 21 healthy volunteers of the

Wavelength dependence of UV induced alterations of epidermal cells in hairless albino mice

SummaryUltraviolet radiation is known to produce DNA damage in epidermal cells that can be removed by the mechanism of excision repair, measured by the number of lightly marked cells in autoradiography. Another effect consists in a delay of the mitotic cycle measured by a reduction of heavy labelled S-phases in the basal cell layer.Irradiation was carried out in hairless albino mice by a Xenon arc lamp with interference filters and with a prism monochromator. Repairing activity was demonstrated in UV C and B with a high peak from 280–290 nm. The relatively low values at 250 and 260 nm are explained by the simultaneously occuring dimer breakage with these wavelengths. This is confirmed by the fact that after 260 nm irradiation we did not find a depression of S-phases in the basal cell layer, while in the range from 270–310 nm there is a clear decrease in the number of replicating cells.There is evidence that the spectrum of UV induced repairable DNA alterations in vivo is broader than the absorption of DNA in vitro.ZusammenfassungDie ultraviolette Strahlung bewirkt in Epidermiszellen DNS-Schäden, die durch den Mechanismus des Excisions-Repair wieder ausgebessert werden. Dieser Vorgang kann am besten autoradiographisch anhand der leicht markierten Zellen bewertet werden. Ein weiterer UV-Effekt besteht in einer Verzögerung des Zellcyclus, was anhand der Zahl markierter S-Phasen abgeschätzt werden kann.Die vorliegenden Versuche wurden an haarlosen Albinomäusen durchgeführt; die Bestrahlung erfolgte mittels einer Xenonlampe unter Vorschaltung von Interferenzfiltern oder eines Prismen-Monochromators. Reparationsaktivität wurde dargestellt nach Bestrahlung mit UV C und B, wobei eine besondere Betonung bei 280–290 nm lag. Die relativ tiefen Werte bei 250 und 260 nm sind nur erklärlich, wenn man bei diesen Wellenlängen schon eine deutliche Dimerspaltung als reversiblen Vorgang annimmt. Das wird gestützt durch die Tatsache, daß bei 260 nm praktisch keine Verzögerung des Zellcyclus zu beobachten ist, was im Bereich 270–310 nm durchaus der Fall ist.Es scheint, daß das Spektrum der UV-induzierten und reparablen DNS-Schäden in vivo weit breiter ist als es die Absorption in vitro vermuten läßt.

Effect of pentoxifylline on sunburn cell formation in a novel supravital human skin model

Background/Aim: The aim of this study was to determine whether pentoxifylline (Pf) has an effect on sunburn cell (SBC) formation in humans.