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Biomedical subjects

T Ruzicka

Publications and source records attributed to T Ruzicka.

At least 217 records · Page 12Linked to original sources
PubMed1997

Congenital erythropoietic porphyria.

Congenital erythropoietic porphyria is a rare autosomal-recessive disorder of the porphyrin metabolism caused by the homozygous defect of uroporphyrinogen III cosynthase. High amounts of uroporphyrin I accumulate in all cells and tissues, reflected by an increased erythrocyte porphyrin concentration and excretion of high porphyrin amounts in urine and feces. Dermal deposits of uroporphyrin frequently induce a dramatic phototoxic oxygen-dependent skin damage with extensive ulcerations and mutilations. Splenomegaly and hemolytic anemia are typical internal symptoms. Skeletal changes such as osteolysis and calcifications are frequent. To date 130 cases of congenital erythropoietic porphyria have been published and are summarized here. Splenectomy, erythrocyte transfusions, and bone marrow transplantation have shown some beneficial effect. The best therapy is the avoidance of sunlight. In the two patients with congenital erythropoietic porphyria described here, oral administration of the oxygen quenchers ascorbic acid and alpha-tocopherol resulted in an improvement in the reduced hemoglobin and erythrocyte concentrations.

Adult↗
PubMed1997

High-dose UVA1 radiation therapy for localized scleroderma.

BACKGROUND: Fibrotic skin lesions in patients with localized scleroderma can cause muscle atrophy, disfigurement, and flexion contractures. There is no effective therapy for this disease. Skin fibrosis is thought to be caused by decreased collagenase activity. Collagenase activity can be induced in dermal fibroblasts by UVA1 irradiation. OBJECTIVE: Our purpose was to assess whether UVA1 radiation therapy is effective for patients with localized scleroderma. METHODS: Patients with localized scleroderma (n = 17) were exposed 30 times to 130 J/cm2 UVA1 (high-dose UVA1 therapy; n = 10) or 20 J/cm2 UVA1 (low-dose UVA1 therapy; n = 7). Therapeutic effectiveness was assessed by evaluation of (1) clinical features, (2) thickness of sclerotic plaques, and (3) cutaneous elastometry. Sequential biopsy specimens from treated lesions were analyzed for collagenase I messenger RNA (mRNA) expression by semiquantitative reverse transcriptase-polymerase chain reaction. RESULTS: In all patients, high-dose UVA1 therapy softened sclerotic plaques, and complete clearance was observed in four of 10 patients. High-dose UVA1 therapy significantly reduced thickness and increased elasticity of plaques. These changes could not be detected in unirradiated control plaques and were still present in 9 of 10 patients 3 months after cessation of therapy. For all factors assessed, high-dose UVA1 was superior to low-dose UVA1 therapy (p = 0.001). High-dose UVA1 therapy increased collagenase I mRNA expression about 20-fold in treated plaques. CONCLUSION: High-dose UVA1 therapy is effective in the treatment of localized scleroderma. Effectiveness is UVA1 dose dependent and is associated with induction of collagenase I expression.

Adult↗
PubMed1997

Photodynamic therapy with 5-aminolaevulinic acid-induced porphyrins of an amelanotic melanoma in vivo.

Of particular interest for photodynamic therapy (PDT) are the endogenously formed and photodynamically active porphyrins produced following topical or systemic application of 65-aminolaevulinic acid (ALA), a haem precursor. Having determined the pharmacokinetics and wavelength dependence of PDT with ALA-induced porphyrins, we analysed the porphyrin metabolites in tumour and surrounding skin. The therapeutic efficacy of PDT using ALA-induced porphyrins was investigated. Amelanotic melanomas (A-Mel-3) were implanted subcutaneously in the back of Syrian golden hamsters (body weight (b.w.), 70-80 g). After 5-7 days, tumours with a volume of approximately 150 mm3 were used for PDT (n = 36). ALA (500 mg kg-1 b.w., pH 6.5) was injected intravenously 45, 90, 150 and 300 min before light irradiation (635 nm, 100 mW cm-2, 100 J cm-2). Tumours with light irradiation only served as controls. The tumour volume was measured after PDT for 28 days. The total porphyrin content was determined in the tumours, the surrounding skin and erythrocytes prior to and 45, 90, 180, 240, 300 and 480 min and 24 h following intravenous injection of ALA (500 mg kg-1 b.w.; n = 32). Porphyrin metabolites were separated by high pressure liquid chromatography (HPLC). Tumour growth was significantly delayed when PDT with ALA was performed 45, 90 or 150 min following intravenous administration. At that time, protoporphyrin (1.8 +/- 0.4 nmol g-1), coproporphyrin (2.2 +/- 0.5 nmol g-1) and uroporphyrin (1.7 +/- 1.4 nmol g-1) were the main metabolites in the tumour tissue. Erythrocytes also contained significant amounts of porphyrins (11.8 +/- 1.3 nmol g-1). The tumour and surrounding skin exhibited a different pattern of porphyrin metabolites. Unexpectedly, a single treatment of PDT with ALA-induced porphyrin resulted in only one complete remission out of six amelanotic melanomas when the final therapeutic outcome was assessed after 28 days. The therapeutic efficacy of PDT with ALA-induced porphyrins can be positively correlated with the fluorescence kinetics previously determined. The analysis of the porphyrin metabolites in amelanotic melanoma by HPLC indicates that the porphyrin accumulation is not due to a decreased activity of ferrochelatase. Moreover, the photodynamic effects may not be mediated solely by porphyrins localized in the tumour parenchyma, but also by significant amounts of porphyrins in the microvasculature. PDT with this endogenous photosensitizer failed to induce complete emission of the treated tumours despite irradiation at the time of maximum porphyrin concentration using the optimum therapeutic wavelength. Thus PDT with ALA-induced porphyrins is less effective in our model relative to that observed for the exogenous photosensitizer Photofrin or synthetic porphycenes after a single treatment.

Aminolevulinic Acid↗
PubMed1997

Ex vivo application of delta-aminolevulinic acid induces high and specific porphyrin levels in human skin tumors: possible basis for selective photodynamic therapy.

In photodynamic therapy with topically applied delta-aminolevulinic acid porphyrins are acting as photosensitizers. The profile of porphyrin metabolites in normal or in neoplastic skin after administration of delta-aminolevulinic acid has not been determined in detail yet. Thus, to study porphyrin biosynthesis in human skin an organ culture model was developed. Explant pieces of normal skin, keratoacanthoma, and basal cell carcinoma were incubated with 1 mM delta-aminolevulinic acid for 36 h. Levels of delta-aminolevulinic acid, porphyrins and porphyrin metabolites were measured in tissues and supernatants. After incubation with delta-aminolevulinic acid, higher porphyrin levels were demonstrated in tumors as compared to normal skin. In supernatants, most of formed porphyrins, preferentially highly carboxylated porphyrin metabolites, were measured. The pattern of synthesized porphyrins differed between normal and neoplastic skin explants. In tissues of basal cell carcinomas protoporphyrin was preferentially shown and tissues of keratoacanthomas were characterized by a predominance of coproporphyrin as compared to normal skin. The results show that explant cultures offer an easy approach to examine the porphyrin biosynthesis of various tissues. The tumor-specific delta-aminolevulinic acid metabolism indicates additional porphyrin metabolites such as coproporphyrin apart from protoporphyrin as effective photosensitizers and may offer a novel approach to tumor-selective photodynamic damage.

Aminolevulinic Acid↗
PubMed1997

Analysis of UVB-modulated gene expression in human keratinocytes by mRNA differential display polymerase chain reaction.

Ultraviolet (UV) light is the most important environmental insult to skin. Even a single exposure to UVB radiation can result in inflammation and may also lead to DNA damage and apoptosis in the acute response of the cutaneous tissue. To elucidate the complex alterations of gene expression in human keratinocytes underlying these UV responses we took advantage of differential display polymerase chain reaction (DD-PCR) technology's ability to detect qualitative and quantitative changes in gene expression in more than two cell populations simultaneously. We demonstrate that low-dose UVB (100 Jm-2) leads to both induction and downregulation of different genes during the 24 h after irradiation in a time-dependent manner. In addition to the identification of known genes as possible effectors or targets in the UV response of human keratinocytes, we here identify a new sequence that is negatively regulated by UVB irradiation and was termed HUR 7 (HaCaT UV repressed). In general our results showed that DD-PCR is a useful tool in the analysis of quantitative changes of mRNA levels in human keratinocytes after UV irradiation. The identification of new UVB-repressed genes offers the opportunity to identify unrecognized molecular mechanisms in the UV response of human cells.

Blotting, Northern↗
PubMed1997

Chronically ultraviolet-exposed human skin shows a higher mutation frequency of mitochondrial DNA as compared to unexposed skin and the hematopoietic system.

Normal ageing processes are associated with an accumulation of mutations within the mitochondrial (mt) DNA. The most frequent mutation is a 4977 base pair (bp) deletion known as common deletion. In order to test the hypothesis that chronically sun-exposed skin is characterized by an increased mutation frequency of mtDNA, the mutation frequency of the common deletion between skin and another replicating tissue (the hematopoietic system) and chronically sun-exposed versus sun-protected skin was compared in the same individuals. This was done by comparing the amount of mutated mtDNA molecules with the whole mitochondrial genome in the same specimen with a semiquantitative polymerase chain reaction method, thus allowing direct comparison of different tissues. In all skin specimens the common deletion could be observed. In contrast only 3 of 10 blood samples revealed detectable amounts of the common deletion. Comparison of sun-exposed versus sun-protected skin exhibited a higher content of the common deletion in sun-exposed skin in 7 of 10 individuals. Additionally, a hitherto undescribed mtDNA mutation was detected exclusively in human skin. These studies indicate that exposure of human skin to solar radiation leads to an accumulation of mtDNA mutations, possibly via oxidative damage, which may play an important role in photoageing.

Adult↗
PubMed1997

Lamotrigine-induced Stevens-Johnson syndrome: demonstration of specific lymphocyte reactivity in vitro.

The novel antiepileptic drug lamotrigine (LTG) is effective as an adjunctive medication in partial seizures. The main adverse effects of LTG are skin eruptions, occurring in 3-10% of the treated patients, but these are rarely severe. The risk of cutaneous side effects is increased in patients receiving sodium valproate comedication, probably by doubling the plasma half-life of LTG due to competition with hepatic glucuronidation. Conversely, the risk can be reduced by adding LTG in a lower dose. Here, we report a patient who developed Stevens-Johnson syndrome (SJS) 5 weeks after adding low-dose LTG comedication to sodium valproate. An LTG-induced pathogenesis of the SJS was considered likely by a positive lymphocyte transformation test to the drug. The patient showed maximal peripheral blood lymphocyte reactivity to 50 micrograms LTG/ml with a stimulation index of 4.7 but not to nontoxic concentrations of sodium valproate. Lymphocytes from untreated controls neither reacted to LTG nor to sodium valproate.

Adult↗
PubMed1997

Porphyrins preferentially accumulate in a melanoma following intravenous injection of 5-aminolevulinic acid.

Systemically, as opposed to topically, administered 5-aminolevulinic acid (ALA) is of increasing interest for photodynamic therapy (PDT) because of more selective and more homogeneous accumulation of porphyrins in neoplastic tissues. This study investigates the profile and the time course of porphyrin metabolites in various tissues following intravenous injection of ALA (0.5 g/kg body weight) into hamsters bearing an amelanotic melanoma (A-Mel-3). ALA injection led to maximum levels of ALA and porphyrins in erythrocytes after 45 min. In tissues, maximum porphyrin levels were detected after 45 min (tumor), 4 h (skin, kidney), and 24 h (liver). Sixfold higher porphyrin levels were observed in tumors as compared to surrounding normal skin at 45 min. Predominant porphyrin metabolites were protoporphyrin (tumor, skin, liver, kidney), coproporphyrin (tumor) and highly carboxylated porphyrins (tumor, skin, kidney). These data suggest optimum efficacy of light irradiation in systemic PDT with ALA within the first two hours after injection. Tumor-specific ALA metabolism yields protoporphyrin and coproporphyrin as the prevailing porphyrin metabolites.

Aminolevulinic Acid↗
PubMed1997

Cutaneous adverse reaction to ciprofloxacin: demonstration of specific lymphocyte proliferation and cross-reactivity to ofloxacin in vitro.

Ciprofloxacin (CPFX) is a widely used fluoroquinolone antibiotic, inducing cutaneous adverse drug reactions in about 1 to 2% of the treated patients. Conclusive diagnosis of drug allergy, however, still remains a major problem in daily clinical practice. Here, we present 2 patients with drug allergy to CPFX. In both cases the clinical suspicion for CPFX as the causative agent was confirmed in vitro by means of the lymphocyte transformation test, whereas epicutaneous patch tests remained negative. In vivo, a small percentage of the drug is biotransformed to the three major metabolites desethylene-, sulfo- and oxociprofloxacin. Though structurally closely related to their mother compound, these metabolites failed to induce in vitro lymphocyte proliferation in both patients. On the other hand, in vitro crossreactivity to ofloxacin, another fluorinated quinolone, could be demonstrated, which to our knowledge has not previously been reported.

Aged↗
PubMed1997

Evaluation of PUVA bath phototoxicity.

Administration of 8-methoxypsoralen in a dilute bath water solution is an effective therapeutic alternative to its systemic application, avoiding systemic side effects. Although PUVA bath photochemotherapy is now widely used, standardized guidelines are not yet available. Therefore, the aim of our study was to determine the optimal time interval between 8-methoxypsoralen bath and UVA irradiation and the persistence of photosensitivity after PUVA bath treatment. In volunteers the highest photosensitivity was observed following UVA irradiation immediately after PUVA bath. A sharp increase of the minimal phototoxic dose could be demonstrated after only 1 h, indicating a rapid loss of 8-methoxypsoralen activity. Irradiation 2 h after 8-methoxypsoralen bath failed to induce any PUVA erythema. This indicates that the optimal time for UVA irradiation is immediately after the 8-methoxypsoralen bath. In contrast to systemic PUVA therapy, 2 h after PUVA bath therapy, the remaining phototoxicity is minimal, so that no stringent restrictions of the patient's behaviour are needed.

Adult↗
PubMed1997

Muir-Torre syndrome: clinical features and molecular genetic analysis.

We report a 62-year-old man with rectal cancer, two keratoacanthomas and multiple sebaceous adenomas, epitheliomas and sebaceous hyperplasia. His brother and father died from colorectal cancer. A subgroup of patients with the Muir-Torre syndrome (MTS) is allelic to the cancer family syndrome. This genetic disorder is caused by an autosomal dominant inherited germline mutation in one of the DNA mismatch repair genes. It is thought that a somatic mutation of the other allele leads to a genomic instability responsible for tumorigenesis. In the patient presented here the instability was detected in two characteristic skin lesions; sebaceous adenoma and epithelioma. The search for a causal germline mutation revealed a frameshift mutation in the mismatch repair gene hMSH2 leading to a truncated protein. A presymptomatic molecular diagnosis can be offered to the children of the patient.

Carcinoma↗
PubMed1996

A proinflammatory activity of interleukin 8 in human skin: expression of the inducible nitric oxide synthase in psoriatic lesions and cultured keratinocytes.

Psoriasis is a common chronic skin disease mediated by cellular immune mechanisms and characterized by an intense neutrophil cell infiltrate and proliferative activation of epidermal keratinocytes. We have previously described the expression of the inducible nitric oxide synthase (iNOS) in epidermal keratinocytes of psoriatic skin lesions. In this study, the role of iNOS in psoriatic inflammation was explored ex vivo in psoriatic skin biopsies and in vitro in primary cultures of human keratinocytes. Messenger RNA for the iNOS enzyme (iNOS mRNA) was detected by reverse transcriptase polymerase chain reaction in skin biopsies from patients with psoriasis, but not in skin specimens from patients with atopic eczema or from healthy volunteers. As demonstrated by in situ hybridization and immunohistochemistry, expression of iNOS mRNA and its gene product was localized to the epidermal keratinocytes of psoriatic skin lesions. In situ hybridization further revealed a complete colocalization of mRNA expression for iNOS with interleukin (IL) 8 receptor-specific mRNA either in the basal germinative cell layer or at focal sites of ongoing neutrophil inflammation in suprabasal cell layers. Because psoriatic keratinocytes have previously been shown to express mRNA transcripts for IL-8, it seemed reasonable to hypothesize that iNOS expression could be induced in an autocrine loop by IL-8. This hypothesis was substantiated by our in vitro experiments showing that a combination of IL-8 and interferon gamma induces the expression of iNOS-specific mRNA and of the functional enzyme in cultured human keratinocytes. These results suggest an important role for iNOS in concert with IL-8 and its receptor early during the formation of psoriatic lesions.

Biopsy↗
PubMed1996

Antioncogene P53 and mitogenic cytokine interleukin-8 aberrantly expressed in psoriatic skin are inversely regulated by the antipsoriatic drug tacrolimus (FK506).

Uncontrolled proliferation of epidermal cells is the most prominent characteristic of psoriasis. This widespread skin disease can be effectively treated with the microbial substance FK506, which acts by modulating gene expression. We, therefore, asked if the drug changes the expression of genes involved in growth regulation (the mitogenic cytokine interleukin-8 (IL-8) and p53, a negative cell cycle regulator) and signal transduction (protooncogenes c-ras, c-raf, and HER-2). Gene expression was monitored by semiquantitative mRNA-PCR and for p53 by immunocytochemistry in cultured primary keratinocytes (KC). In addition, p53 expression was analysed in skin biopsies of psoriatic patients. After 1-3 hr, IL-8 mRNA levels were dose-dependently decreased in tacrolimus (FK506)-treated cells. Protooncogene expression was not significantly altered. Interestingly, p53 transcription was clearly induced by FK506 treatment. This tendency could be verified on the protein level by immunocytochemistry. In contrast, p53 expression was decreased in lesional psoriatic as compared to normal skin, providing evidence that not only posttranslational modification of the p53 protein, but also transcriptional modulation of the p53 gene, are involved in pathological processes and pharmacological drug action in skin. Together with earlier results showing downmodulation for IL-8 receptor type A expression in cultured KC treated with FK506, these results suggest that both the mitogenic IL-8/IL-8R system and the cell cycle inhibitor p53 represent potential targets for the antipsoriatic action of the drug, whereas protooncogenes acting downstream in mitogenic signal transduction cascades are unaffected. The differential modulation of an entire set of genes provides evidence for the specificity of the drug effects and rules out nonspecific toxic effects on KC.

Dose-Response Relationship, Drug↗