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Biomedical subjects

A Tanew

Publications and source records attributed to A Tanew.

At least 19 recordsLinked to original sources
PubMed2003

Observer-blind, randomized, intrapatient comparison of a novel 1% coal tar preparation (Exorex) and calcipotriol cream in the treatment of plaque type psoriasis.

BACKGROUND: In a recent pilot study a novel, patented fatty acid-based 1% coal tar preparation (Exorex) has been found to be similar in efficacy to calcipotriol in the treatment of psoriasis. OBJECTIVES: Our aim was to investigate the therapeutic efficacy, safety and cosmetic acceptability of the new 1% coal tar preparation in comparison with calcipotriol cream in a larger patient cohort. PATIENTS AND METHODS: Forty patients with chronic plaque type psoriasis were included in this randomized, observer-blind, intrapatient comparison trial. In each patient two comparable target plaques were treated twice daily with 1% coal tar preparation or calcipotriol cream. At the onset of therapy and at weeks 2, 4, 6 and 8, the response to treatment was determined by the psoriasis severity index (PSI) that assesses the degree of erythema, infiltration and scaling of the psoriatic lesions on a five-point scale. In addition, all treatment-related side-effects were recorded and cosmetic acceptability of both treatments was rated every second week by the patients. After complete or near complete clearing the patients were followed up until relapse or for a maximum period of 18 months. RESULTS: Thirty-eight patients completed the study. At termination of the trial the mean +/- SD baseline PSI score of 9.2 +/- 1.5 was reduced to 3.0 +/- 2.9 by 1% coal tar preparation and to 2.8 +/- 2.7 by calcipotriol. The mean PSI reduction between baseline and final assessment did not differ significantly between 1% coal tar preparation and calcipotriol (P = 0.77). The mean intraindividual difference in reduction of PSI score between 1% coal tar preparation and calcipotriol was 0.1 score points (95% confidence interval - 0.84 to + 0.63). No difference between either preparation was observed with regard to time until relapse. Itching was caused by 1% coal tar preparation in four patients and by calcipotriol in one patient. Unpleasant odour or staining of the 1% coal tar preparation was reported by six patients, whereas one patient complained about the smell of the calcipotriol cream. CONCLUSIONS: The novel 1% coal tar preparation was found to be comparably as effective as calcipotriol in treating psoriasis. Tolerability and cosmetic acceptability was better for calcipotriol. Taking into consideration that the coal tar preparation is considerably less expensive than calcipotriol this new product appears as a very useful topical medication for chronic plaque type psoriasis.

Adult↗
PubMed2003

Autoimmune diseases in vitiligo: do anti-nuclear antibodies decrease thyroid volume?

An increased prevalence of autoimmune thyroiditis (AT) in vitiligo patients is well known. The aim of this study was firstly, to evaluate the clinical course of patients with both vitiligo and AT and secondly, to identify additional autoimmune disorders affecting the thyroid gland in a large cohort of vitiligo patients. We analysed a study group of 106 vitiligo patients and 38 controls. A detailed thyroid examination including sonography was performed in all study participants. In addition, the study participants were HLA typed and screened for various autoimmune disorders. AT was significantly more frequent in vitiligo patients than in controls (21%versus 3%; P < 0.01). In 12 of the 22 patients with AT, vitiligo was the initial disease preceding AT by 4-35 years. In the other 10 patients with AT, both vitiligo and AT were diagnosed within one year. There were two individuals with diabetes mellitus type 1 and a single patient with Addison's disease. Anti-nuclear antibody (ANA), anti-smooth muscle cell antibody, and parietal cell antibody levels occurred with a similar frequency in patients and controls. In all vitiligo patients with both elevated ANA levels and AT (n = 6), the atrophic but not the goitrous variant was diagnosed. These vitiligo patients with both AT and elevated ANA levels had a significantly smaller thyroid volume compared to the vitiligo patients with AT whose ANA levels were normal (6.7 +/- 4.5 ml versus 13.4 +/- 9.1 ml, respectively; P < 0.05). The same was found in the entire study group: Thyroid volume of all vitiligo patients (with or without concomitant AT) was significantly smaller in the presence of ANA (6.9 +/- 5.3 versus 10.5 +/- 5.9 ml, respectively; P < 0.05). However, this phenomenon was not observed in the control group. There was a trend for a decreased frequency of HLA-DR3 (6.7%versus 23%) in our study group, but after correction for the number of comparisons, no HLA-allele was statistically significant associated neither with vitiligo nor with multiple autoimmune diseases in our patient sample. Our findings suggest that AT is the most frequent autoimmune disease associated with vitiligo. In our patients, AT presented simultaneously or after the onset of vitiligo but not before. Elevated ANA levels were associated with the atrophic variant of AT and may affect the volume of the thyroid gland, and there was no statistically significant association with the HLA system.

Adolescent↗
PubMed2002

Hereditary, focal, transgressive palmoplantar keratoderma with associated clinical findings: a new entity?

We report on a 24-year-old male originating from Yugoslavia with a focal, transgressive palmoplantar keratoderma presumably inherited as an autosomal recessive trait. Associated clinical findings were hyperkeratotic lichenoid papules on the knees and elbows, psoriasis-like lesions in the groins and on the scalp, a spotty or reticulate hyperpigmentation of the face, trunk and extremities and a partial alopecia of the left eyebrow and eyelashes. The patient's sister was affected by similar but less pronounced cutaneous changes. Although our case shares some similarities with other hereditary palmoplantar keratodermas there remain substantial differences. We therefore believe this case to represent a new entity.

Adult↗
PubMed2002

A comparison of psoralen plus ultraviolet A (PUVA) monotherapy, tacalcitol plus PUVA and tazarotene plus PUVA in patients with chronic plaque-type psoriasis.

BACKGROUND: Numerous studies have shown that the additional administration of topical or systemic antipsoriatic agents might serve as an effective means to increase the efficacy of photochemotherapy [psoralen plus ultraviolet (UV) A (PUVA)] for psoriasis. OBJECTIVES: To compare the therapeutic response to tacalcitol plus PUVA, tazarotene plus PUVA and PUVA monotherapy in patients with chronic plaque-type psoriasis. In addition, we also assessed the duration of remission induced by each regimen and the tolerability of the two combination treatments. METHODS: Thirty-one patients with chronic plaque-type psoriasis were included in this observer-blinded, intrapatient comparison trial. PUVA treatment was given four times weekly. Additionally, tacalcitol ointment and 0.1% tazarotene gel were applied separately on two target areas once daily in the evening. At the onset of therapy and every 2 weeks thereafter the response to treatment was determined by the Psoriasis Severity Index score, which assesses the degree of erythema, infiltration and scaling of the psoriatic lesions. After complete or near complete clearing patients were followed-up until relapse. RESULTS: Twenty-four patients completed the study. The treatment requirements to induce complete or near complete clearing were significantly lower for both combination treatments than for PUVA monotherapy (P < 0.01). The median cumulative UVA dose and number of exposures were 30.6 J cm-2 (95% confidence interval, CI 22.5-71.2) and 14 (95% CI 11-16) for tacalcitol plus PUVA, 32.3 J cm-2 (95% CI 22.5-73.8) and 14 (95% CI 11-19) for tazarotene plus PUVA, and 37.0 J cm-2 (95% CI 29.5-83.9) and 16 (95% CI 14-22) for PUVA monotherapy. No difference between the three regimens was observed with regard to duration of remission. Adverse reactions occurred more often with 0.1% tazarotene than with tacalcitol but were in general mild and completely reversible upon using a lower concentration of 0.05% tazarotene. CONCLUSIONS: Tacalcitol ointment and tazarotene gel are both comparably effective in improving the therapeutic result of PUVA therapy in patients with chronic plaque-type psoriasis. Besides accelerating the treatment response, both agents, by virtue of their UVA dose-sparing effect, might also help to reduce possible long-term hazards of PUVA treatment.

Adult↗
PubMed2002

Photodynamic therapy using topical methyl 5-aminolevulinate compared with cryotherapy for actinic keratosis: A prospective, randomized study.

BACKGROUND: Actinic keratoses (AKs) are the most common premalignant tumors. Without treatment, a significant number of patients with AK will experience squamous cell carcinoma. Photodynamic therapy (PDT) using the new highly selective photosensitizer methyl 5-aminolevulinate is a promising new treatment modality for AK. OBJECTIVE: We investigated the complete response rates, cosmetic outcome, and patient satisfaction after photodynamic therapy (PDT) using methyl 5-aminolevulinate (Metvix) versus cryotherapy in the treatment of AKs. METHODS: Patients were randomized to receive either cryotherapy with liquid nitrogen spray or PDT using methyl 5-aminolevulinate cream 160 mg/g, 3 hours application time, and red light (75 J/cm(2)). RESULTS: Efficacy results from 193 patients with 699 lesions (92% face/scalp and 93% thin/moderately thick) were analyzed. Overall complete response rates after 3 months were 69% for PDT and 75% for cryotherapy. Both treatments gave higher response rates in thin lesions (PDT 75%, cryotherapy 80%). PDT gave better cosmetic results and higher patient satisfaction than cryotherapy. CONCLUSION: PDT using methyl 5-aminolevulinate is an attractive treatment option for patients with AK, with a response rate similar to that of cryotherapy, but with superior cosmetic results and high patient satisfaction.

Administration, Topical↗
PubMed2001

Correlation between 8-methoxypsoralen bath-water concentration and photosensitivity in bath-PUVA treatment.

BACKGROUND: Bath-PUVA treatment, originally established in Scandinavia, offers several advantages over oral PUVA and has become increasingly popular in recent years. Outside Scandinavia 8-methoxypsoralen (8-MOP) is the prevailing photosensitizer for this PUVA modality and is used arbitrarily in a wide range of concentrations. Up to the present, data are lacking on the impact of 8-MOP bath-water concentration on UVA dosimetry. OBJECTIVE: We investigated the influence of increasing 8-MOP bath-water concentrations on photosensitivity in bath-PUVA treatment. METHODS: Fifteen healthy volunteers without abnormal photosensitivity or recent exposure to ultraviolet radiation were included in an intraindividually controlled comparison study. In all volunteers the minimal phototoxic dose (MPD) was determined on the volar side of their forearms after immersion for 20 minutes in 4 different 8-MOP bath-water concentrations (0.5, 1, 2.5, and 5 mg/L). The correlation between 8-MOP concentration and photosensitivity (defined as the reciprocal value of the MPD) was analyzed by linear regression analysis. In addition, the time course of erythema formation and the UVA dose-erythema response curve was assessed for each psoralen concentration. RESULTS: The median MPD and the 25%-75% interquartile were 5.7 J/cm(2) (5.7-8), 4 J/cm(2) (4-5.7), 2.8 J/cm(2) (2.8-5.7), and 2 J/cm(2) (2-2.8) at an 8-MOP concentration of 0.5, 1, 2.5, and 5 mg/L, respectively. Linear regression analysis revealed a significant correlation between 8-MOP bath-water concentration and photosensitivity (r = 0.98; P =.019). Bath-PUVA-induced erythema peaked after a median time interval of 3 days, with a range of 2 to 4 days. The slope of the UVA dose-erythema response curve was similar for all psoralen concentrations. CONCLUSION: UVA dose requirements in bath-PUVA treatment decrease linearly with increasing 8-MOP concentrations. A single MPD assessment at 72 hours after the UVA exposure is inappropriate for accurate determination of the patients' photosensitivity. The hazard of wrong UVA dosimetry is comparable at all psoralen concentrations.

Adult↗
PubMed2001

Oral dexamethasone pulse treatment for vitiligo.

BACKGROUND: Oral corticosteroid pulse therapy has provided inconsistent results in the treatment of Indian patients with vitiligo. OBJECTIVE: We wanted to evaluate the efficacy, safety, and tolerability of oral dexamethasone pulse therapy in a cohort of Austrian patients with vitiligo. METHODS: Twenty-nine patients with vitiligo were included in the study. Of these, 25 had progressive and 4 had stable disease. The patients were given weekly pulses of 10 mg dexamethasone each on 2 consecutive days followed by 5 days off treatment for a maximum period of 24 weeks. Clinical response and side effects were evaluated in monthly intervals. Plasma cortisol and corticotropin levels were monitored before and up to 6 days after the dexamethasone pulse in the first and fourth week of treatment in 14 patients. RESULTS: After a mean treatment period of 18.2 +/- 5.2 weeks, the disease activity was arrested in 22 of 25 patients (88%) who had active vitiligo before the study. Marked repigmentation occurred in 2 patients (6.9%) and moderate or slight repigmentation in 3 patients (10.3%) each. No response was noted in 21 patients (72.4%). Side effects were recorded in 20 patients (69%) and included weight gain, insomnia, acne, agitation, menstrual disturbance, and hypertrichosis. Plasma cortisol and corticotropin values were markedly decreased 24 hours after the second dexamethasone dose, yet returned to baseline values within the off treatment period before the next dexamethasone pulse. CONCLUSION: Our data show that oral dexamethasone pulse treatment is effective in arresting progression of vitiligo yet fails to induce satisfactory repigmentation in the great majority of our patient cohort. Mild to moderate side effects are common with this treatment modality; however, sustained suppression of endogenous cortisol production does not occur with the pulse regimen.

Administration, Oral↗
PubMed2001

High-dose versus medium-dose UVA1 phototherapy for patients with severe generalized atopic dermatitis.

BACKGROUND: Several studies have demonstrated the efficacy of UVA1 (340-400 nm) phototherapy for patients with severe atopic dermatitis. However, the optimum treatment dose has yet to be determined. Although in seminal investigations high UVA1 doses were used, comparable results were reported in recent studies with a medium-dose regimen. OBJECTIVE: Our purpose was to compare the efficacy of high-dose with medium-dose UVA1 phototherapy for patients with severe generalized atopic dermatitis. METHODS: Ten adult patients with a median baseline SCORAD score of 67 were enrolled in an investigator-blinded, bilateral comparison study. Treatment was given 5 times weekly over a period of 3 weeks on an outpatient basis. Irradiation was performed by exposing one half of the patient's body to high-dose UVA1 (< or =130 J/cm(2)), and the contralateral body side received only half that dose. The clinical response was assessed after 5, 10, and 15 treatments. After completion of the study, patients were followed up for 6 months to evaluate the duration of clinical improvement. RESULTS: All but one patient responded favorably to treatment. High-dose UVA1 led to a decrease of the median SCORAD score by 33.4% after 1 week, 38.4% after 2 weeks, and 34.7% after 3 weeks. The respective values for the medium-dose regimen were 29.7%, 36.4%, and 28.2%. The difference in efficacy between the two dosages remained below the level of significance at all time points. Relapses occurred after a median of 4 weeks. Time of onset and severity of relapse were the same for both doses. CONCLUSION: Our data support previous uncontrolled observations that medium-dose UVA1 is comparably as effective as high-dose treatment for patients with severe generalized atopic dermatitis. Irrespective of the dose regimen, follow-up examinations revealed early relapse in the majority of patients.

Adult↗
PubMed2001

Pruritometer 2: portable recording system for the quantification of scratching as objective criterion for the pruritus.

Studies to evaluate therapies for itching (pruritus) related diseases often require the quantification of the itch sensation. Like all subjective symptoms the evaluation of itching is difficult and can only be done indirectly. With the Pruritometer 2 a measuring system is introduced that evaluates itching by detecting scratching movements. Based on the Pruritometer 1, that processes the signals of a piezoelectric vibration sensor, fixed on the midfinger of the patients dominant hand, and triggers a simple counter, the Pruritometer 2 allows to store the scratch activity during a 24 hours period. For each adjustable time slice of this time period, the amount of scratches and the scratch intensity are recorded. All data can be transferred to a PC via infrared link for further processing with a standard software package. An additional PC-software allows to set various parameters for optimal scratch detection and to test the patient attached system, also via the infrared link. All electronic components are shockproof encapsulated in a milled housing and are attached to a textile watchstrap that is worn by the patient like a wristwatch.

Equipment Design↗
PubMed2000

Correlation between bathing time and photosensitivity in 8-methoxypsoralen (8-MOP) bath PUVA.

Bath PUVA (psoralen plus ultraviolet A) using 8-methoxypsoralen has become increasingly popular in recent years as an effective treatment option for a continuously expanding range of skin disorders. Among the various variables of bath PUVA treatment, the impact of bathing time on photosensitivity has never been investigated in detail. We therefore determined the threshold UVA dose for erythema induction after different bathing periods. A marked influence of bathing time on photosensitivity was found. Increasing the soaking period from 5 min to 30 min resulted in a greater than 60% reduction of the minimal phototoxic and minimal perceptible phototoxic dose. Our results demonstrate that the duration of the psoralen bath is a critical parameter in bath PUVA treatment and has a major influence on UVA dose requirements.

Adult↗
PubMed2000

Half-side comparison study on the efficacy of 8-methoxypsoralen bath-PUVA versus narrow-band ultraviolet B phototherapy in patients with severe chronic atopic dermatitis.

In patients with severe chronic atopic dermatitis (AD), both photochemotherapy [psoralen ultraviolet A (PUVA)] and narrow-band (TL-01) UV B phototherapy have been reported to be very effective. As no data exist on the relative therapeutic efficacy of these two regimens, we performed a randomized investigator-blinded half-side comparison study on 12 patients with severe chronic AD. Half-side irradiation with threshold erythemogenic doses of 8-methoxypsoralen bath-PUVA and narrow-band UVB was performed three times weekly over a period of 6 weeks. The severity of the disease was assessed separately for the paired halves of the patients' bodies by a modified SCORAD score at baseline and after 2, 4 and 6 weeks of treatment. Ten of the 12 patients completed the trial. All but one showed marked improvement or complete remission with both treatments. The mean baseline SCORAD score decreased by 65.7% by the bath-PUVA treatment and by 64.1% by the narrow-band UVB treatment (P = 0.48). No serious adverse reactions to either of the two regimens were observed. Our data confirm the high efficacy of bath-PUVA and narrow-band UVB phototherapy in the treatment of patients with chronic severe AD. Both regimens appear to be equally effective when administered in equi-erythemogenic doses.

Adult↗
PubMed2000

Narrow-band ultraviolet B (ATL-01) phototherapy is an effective and safe treatment option for patients with severe seborrhoeic dermatitis.

BACKGROUND: Seborrhoeic dermatitis is a common papulosquamous dermatosis affecting 2-10% of the adult population. Current treatment options are limited and not always satisfactory. Objectives We aimed to investigate the efficacy of narrow-band ultraviolet (UV) B (TL-01) phototherapy as an alternative treatment for seborrhoeic dermatitis. METHODS: Eighteen patients with severe disease were enrolled in an open prospective study. Treatment was given three times weekly until complete clearing or to a maximum of 8 weeks. A clinical score assessing erythema, scaling, infiltration and pruritus was performed at baseline and every 2 weeks thereafter. Additionally, the patients were asked to rate the intensity of pruritus on a visual analogue scale. After completion of the study the patients were followed up to determine the median time interval until recurrence. RESULTS: All patients responded favourably to treatment, with six showing complete clearance and 12 marked improvement. The median clinical score decreased from 7.5 (range 4-8) at baseline to 0.5 (range 0-3) after 8 weeks of treatment (P = 0.005). The median pruritus score decreased from 4.5 (range 0-8) at baseline to 0 (range 0-3) at week 8 (P = 0.008). Relapses occurred in all patients after a median of 21 days (range 12-40). No side-effects of treatment were observed except occasional episodes of a moderate erythemal response. CONCLUSIONS: Narrow-band UVB phototherapy appears to be a very effective and safe treatment option for patients with severe seborrhoeic dermatitis.

Adolescent↗
PubMed2000

Keratinocytes express the CD146 (Muc18/S-endo) antigen in tissue culture and during inflammatory skin diseases.

The CD146 (or MUC18/MEL-CAM) antigen is a cell adhesion molecule of the immunoglobulin superfamily. Besides in melanoma, expression of CD146 antigen has been demonstrated in breast epithelia and hair follicles. We studied its expression by human keratinocytes in culture as well as in neoplastic and inflammatory skin diseases. Staining of primary cultured keratinocytes revealed expression of CD146 on the cell membrane, preferentially on cell-cell contact sites. Western blot analysis of keratinocytes detected a band of approximately 113 kDa, corresponding to the CD146 protein. In contrast to primary keratinocytes, neither CD146 protein nor mRNA expression was found in the keratinocyte-derived cell lines A431 and HaCaT. Treatment of keratinocytes with the proinflammatory cytokines interleukin-1 and interleukin-6, tumor necrosis factor-alpha, and interferon-gamma, resulted in no change of CD146 expression and incubation with phorbol 12-myristate 13-acetate led to a reduction of CD146 on keratinocytes. By contrast, when culturing keratinocytes in medium devoid of growth supplements, a distinct upregulation was observed as compared with culture in fully supplemented medium. In normal human epidermis expression of the CD146 antigen was not detectable. It was strongly upregulated, however, on suprabasal keratinocytes in psoriasis, in lichen planus, in the epidermis overlying skin neoplasms, and in viral warts. In squamous cell carcinomas and basal cell carcinomas only a minority of tumor cells expressed CD146. Our findings suggest that the CD146 antigen represents an activation marker of keratinocytes and may be involved in cutaneous inflammatory tissue reaction.

Antigens, CD↗
PubMed1999

Narrowband UV-B phototherapy vs photochemotherapy in the treatment of chronic plaque-type psoriasis: a paired comparison study.

OBJECTIVE: To compare the therapeutic efficacy of narrowband (TL-01) UV-B phototherapy vs photochemotherapy (psoralen-UV-A [PUVA]) in patients with chronic plaque-type psoriasis. DESIGN: Open, nonrandomized, intraindividually controlled paired comparison study. SETTING: Phototherapeutic unit in a university hospital. PATIENTS: Twenty-five patients with chronic plaque-type psoriasis. INTERVENTIONS: Paired irradiations with threshold erythemogenic doses of narrowband UV-B and PUVA were given to the patients' dorsal aspect including the arms and legs. Treatment was performed 3 times weekly until complete or almost complete clearing with one or both regimens or over a maximum period of 18 exposures. MAIN OUTCOME MEASURES: Assessment of the Psoriasis Area and Severity Index (PASI) in each half of the patient's dorsal aspect before and after treatment with the 2 regimens. RESULTS: The median pretreatment PASI score of 16 (range, 6.2-23.4) was reduced by 84% to 2.5 (range, 0-12.6) by the narrowband UV-B treatment and by 89% to 1.8 (range, 0-8.2) by the PUVA treatment. Statistical analysis of these data showed a tendency for PUVA being superior to narrowband UV-B although the difference remained below the level of significance (P = .17). However, a clear effect of the pretreatment PASI score on the therapeutic outcome was found. Patients with higher baseline PASI scores responded significantly better to PUVA than to narrowband UV-B (P = .03). CONCLUSIONS: Our data demonstrate that in many patients with plaque-type psoriasis, narrowband UV-B is comparably as effective as PUVA and, given the lack of photosensitizer-related adverse reactions and the possibly lower long-term cancer risk, can be considered as first-line treatment. Treatment with PUVA, on the other hand, remains the mainstay for patients with high PASI scores who do not respond or whose psoriasis cannot be controlled adequately by narrowband UV-B.

Chronic Disease↗
PubMed1999

Half-side comparison of erythemogenic versus suberythemogenic UVA doses in oral photochemotherapy of psoriasis.

BACKGROUND: Early American and European multicenter trials on the efficacy of photochemotherapy (PUVA) for psoriasis have clearly shown that the treatment protocol has a crucial impact on the cumulative UVA dose required for clearing patients. Most, if not all, treatment protocols rely on the PUVA-induced erythema as a guideline for UVA dosimetry. OBJECTIVE: Our aim was to investigate whether phototoxic erythema is integral to an optimized PUVA protocol or reflects an unnecessary overexposure of patients. METHODS: A standard high-dose UVA regimen using minimal phototoxic doses (MPD) was compared against two different low-dose regimens. To this purpose a bilateral comparison study was performed on 31 patients and divided in two parts. In the first trial on 14 patients, half of each patient's body was irradiated at each visit with 1 MPD, whereas the other half received only two thirds of the MPD. In the second trial on 17 patients treatment with 1 MPD was compared against treatment with one half of the MPD. RESULTS: A total of 27 patients (12 patients in the first trial, 15 patients in the second trial) completed the study. In both trials the suberythemogenic doses were therapeutically as effective as the minimal phototoxic doses. CONCLUSION: We conclude that PUVA-induced erythema is not a prerequisite for effective psoriasis treatment and that a low-dose UVA regimen is a promising approach to increase the short- and long-term safety of photochemotherapy.

Administration, Oral↗
PubMed1999

Ultrastructural changes in PAM cells after photodynamic treatment with delta-aminolevulinic acid-induced porphyrins or photosan.

Photodynamic therapy (PDT) is the combination of a photosensitizing drug (Ps) with light in the presence of oxygen leading to the generation of reactive molecular species and destruction of cancer cells. In this study we compared PDT with two Ps, the hematoporphyrin derivative Photosan (Ph) and delta-aminolevulinic acid (ALA)-induced endogenous protoporphyrin IX, with respect to mitochondrial function and ultrastructural alterations. The effects of PDT were investigated in PAM 212 cells after different Ps incubation times, light doses, and post-treatment periods. Both Ps induced a light dose-dependent impairment of the mitochondrial function with the dose-response curve being steep for ALA and flat for Ph. The prolongation of the incubation time from 4 to 20 h resulted in an increased reduction of mitochondrial activity after ALA PDT but not after Ph PDT. Treatment with an irradiation dose that decreased mitochondrial activity by 50% (IC50) led to early and profound changes of mitochondrial morphology in ALA photosensitized cells, whereas photosensitization with Ph resulted in more pronounced alterations of lysosomes. We conclude that at bioequivalent sublethal PDT exposures of PAM 212 cells, ALA-induced damage is primarily restricted to mitochondria, whereas Ph-induced cytotoxicity is mediated by damage of the lysosomal system.

Aminolevulinic Acid↗