The use of high-resolution ultrasonography for preoperative detection of metastases in sentinel lymph nodes of patients with cutaneous melanoma.

BACKGROUND: Sentinel lymph node biopsy (SLNB) reliably assesses the status of the regional lymph node basins and provides prognostic information in patients with cutaneous melanoma, but is logistically demanding and expensive. OBJECTIVE: The aim of this study was to evaluate the ability of high resolution B-mode ultrasonography (US) for pre-operative identification and characterization of sentinel lymph nodes (SLN) in patients with cutaneous melanoma. PATIENTS AND METHODS: In a prospective trial, the use of high resolution US was assessed in 25 consecutive patients with cutaneous melanoma identified for SLNB, first, for its value in primary detection of SLN, and, second, for its value in the correct assessment of SLN after lymphoscintigraphic mapping. RESULTS: High resolution B-mode US correctly identified two of 6 positive SLN. The sensitivity, specificity, positive predictive value, and negative predictive value of US were 33.3% (95% CI 43.3-77.7), 100.0% (95% CI 88.1-100.0), 100.0% (95%CI 15.8-100.0) and 87.9% (95% CI 71.8-96.6), respectively. CONCLUSION: High resolution B-mode US cannot replace SLNB, especially in the detection of micrometastases, but it remains the most important method to assess the lymph node status for macrometastases presurgically.

Leser-Trelat sign in metastasized malignant melanoma.

The Leser-Trelat sign is defined as the association of multiple, eruptive seborrheic keratoses with an internal malignancy of a usually advanced stage. We report the case of malignant melanoma in an 82-year-old man covered with hundreds of greyish-dark seborrheic keratoses resembling a Christmas tree pattern, who was diagnosed with metastasized malignant melanoma involving the parotid gland and lymph nodes. Though the pathogenesis of Leser-Trelat sign is still unknown, spontaneous regression of the seborrheic keratoses following tumor reduction described in some cases argues for a paraneoplastic origin of this highly instructive clinical entity. Physicians should consider a workup for internal malignancy in patients presenting with multiple eruptive seborrheic keratoses.

Characterization and quantification of triple helix formation in chromosomal DNA.

DNA-binding molecules that recognize specific sequences offer a high potential for the understanding of chromatin structure and associated biological processes in addition to their therapeutic potential, e.g. as positioning agents for validated anticancer drugs. A prerequisite for the development of DNA-binding molecules is the availability of appropriate methods to assess their binding properties quantitatively at the desired target sequence in the human genome. We have further developed a capture assay to assess triplex-forming oligonucleotide (TFO) binding efficiency quantitatively. This assay is based on bifunctional, psoralen and biotin-conjugated, TFOs and real-time PCR analysis. We have applied this novel quantification method to address two issues that are relevant for DNA-binding molecules. First, we have compared directly the extent of TFO-binding in three experimental settings with increasing similarity to the situation in vivo, i.e. naked genomic DNA, isolated cell nuclei, or whole cells. This comparison allows us to characterize factors that influence genomic triplex formation, e.g. chromosomal DNA organization or intracellular milieu. In isolated nuclei, the binding was threefold lower compared to naked DNA, consistent with a decreased target accessibility int he nucleosomal environment. Binding was detected in whole cells, indicating that the TFO enters the nucleus and binds to its target in intact cells in vivo, but the efficiency was decreased (tenfold) compared to nuclei. Secondly, we applied the method to characterize the binding properties of two different TFOs targeting the same sequence. We found that an antiparallel-binding GT-containing TFO bound more efficiently, but with less target sequence selectivity compared to a parallel-binding CU-containing TFO. Collectively, a sensitive method to characterize genomic triplex formation was described. This may be useful for the determination of factors driving TFO binding efficiency and, thus, may improve the usefulness of triplex-mediated gene targeting for studies of chromatin structure as well as for therapeutic antigene strategies.

Triple helix-mediated inhibition of gene expression is increased by PUVA.

The combination of psoralens with UVA is used as PUVA therapy for psoriasis and other skin diseases. UVA-induced psoralen/DNA photoadducts act via suppression of DNA replication and cell proliferation, but do not sufficiently repress gene transcription. To explore whether PUVA may also be used for gene repression, psoralen was conjugated to a triplex-forming oligonucleotide (TFO) that targets a gene sequence of ICAM-1, a key molecule in cutaneous inflammation. Triplex formation between TFO and target sequence was detected by non-denaturing gel electrophoresis. UVA-irradiation induced psoralen cross-links at the triplex-duplex junction as verified by denaturing gel electrophoresis. When the target sequence was placed within the transcribed portion of the chloramphenicol acetyltransferase (CAT) gene, TFO inhibited CAT expression in A431 cells. Inhibition was sequence-specific, since a scrambled control oligonucleotide or mismatched or scrambled target sequences failed to inhibit CAT expression. Inhibition was not significant without UVA exposure, but was strongly enhanced by PUVA-mediated cross-links at the TFO target site. These results suggest that TFO may add a new quality to PUVA therapy by transcriptionally repressing pathogenically relevant genes, in addition to antiproliferative PUVA effects. TFO designed to repress only after PUVA activation may allow the development of a cutaneous organ specific strategy for gene repression.

[Symmetrical peripheral gangrene of unknown etiology]. / Symmetrische periphere Gangrän unbekannter Atiologie.

We describe the case of a 19-year-old female patient who presented with acute symmetrical peripheral gangrene (SPG), including all fingers and toes. Further diagnostic work-up did not reveal any underlying condition other than a non-specific transient cryoglobulinemia. Despite immediate anticoagulopathic and anti-inflammatory treatment, all fingers and toes had to be amputated.

[Therapy of pruritus associated with skin diseases with the serotonin receptor antagonist ondansetron]. / Behandlung von Pruritus als Symptom von Hauterkrankungen mit dem Serotonin-Rezeptorantagonisten Ondansetron.

BACKGROUND: Pruritus is often a stressing symptom and a therapeutic challenge. We report our experience with the serotonin receptor antagonist ondansetron in the symptomatic treatment of pruritus accompanying various skin diseases. PATIENTS AND METHODS: The influence of ondansetron (8-12 mg orally per day) on pruritus was assessed in twelve patients with various skin disorders. The intensity of pruritus was quantitated daily by a visual analogue scale over the time period of one week before, during, and one week after treatment. RESULTS: Ondansetron decreased pruritus intensity in prurigo simplex (four patients), asteatotic eczema (two patients), parapsoriasis en plaques, and pruritus of unknown origin (one patient each). One of two patients with atopic dermatitis experienced relief, whereas no benefit was observed in urticaria factitia and notalgia paraesthetica (one patient each). CONCLUSIONS: Ondansetron may ameliorate the concomitant pruritus of some dermatologic diseases.

Protease inhibitors prevent plasminogen-mediated, but not pemphigus vulgaris-induced, acantholysis in human epidermis.

Pemphigus is an autoimmune blistering disease of the skin and mucous membranes. It is caused by autoantibodies directed against desmosomes, which are the principal adhesion structures between epidermal keratinocytes. Binding of autoantibodies leads to the destruction of desmosomes resulting in the loss of cell-cell adhesion (acantholysis) and epidermal blisters. The plasminogen activator system has been implicated as a proteolytic effector in pemphigus. We have tested inhibitors of the plasminogen activator system with regard to their potential to prevent pemphigus-induced cutaneous pathology. In a human split skin culture system, IgG preparations of sera from pemphigus vulgaris patients caused histopathologic changes (acantholysis) similar to those observed in the original pemphigus disease. All inhibitors that were tested (active site inhibitors directed against uPA, tPA, and/or plasmin; antibodies neutralizing the enzymatic activity of uPA or tPA; substances interfering with the binding of uPA to its specific cell surface receptor uPAR) failed to prevent pemphigus vulgaris IgG-mediated acantholysis. Plasminogen-mediated acantholysis, however, was effectively antagonized by the synthetic active site serine protease inhibitor WX-UK1 or by p-aminomethylbenzoic acid. Our data argue against applying anti-plasminogen activator/anti-plasmin strategies in the management of pemphigus.