Ultraviolet radiation induction of squamous cell carcinomas in p53 transgenic mice.

Mutations of the p53 gene have been implicated in the pathogenesis of cutaneous squamous cell carcinoma (SCC). To examine the role of p53 in skin carcinogenesis, we observed the development of skin cancers in p53 transgenic mice which carry multiple copies of a mutant allele of the p53 gene with or without chronic UVB radiation. Thirty-one tumors developed in 19 UV-irradiated p53 transgenic mice versus 14 of 19 in the control group; 9 p53 transgenic mice but none of the control mice developed multiple tumors. Histologically. 14 of 14 tumors in the CD-1 mice were SCCs. In the p53 transgenic mice, 25 of 31 tumors were SCCs, and 6 were benign tumors. The mean time to appearance of tumors did not differ between CD-1 mice (26.3 weeks) and the p53 transgenic mice (25.7 weeks; P = 0.512). The p53 protein, which was undetectable by immunohistochemistry in the keratinocytes of CD-1 mice, was elevated in 93% (13 of 14) of tumors from CD-1 mice. These data indicate that mutation of the p53 gene is an important step in the development of SCC. p53 mutations do not alter the latent period of UV-induced SCC but significantly increase the number of tumors and the propensity for multiple tumor development.

Expression of apoptosis regulators in cutaneous malignant melanoma.

Metastatic malignant melanoma (MM) is usually incurable and responds poorly to chemotherapy. Because many cytotoxic drugs cause cell death by inducing apoptosis, an imbalance of apoptosis regulatory proteins may contribute to MM treatment resistance. We have previously shown reduced expression of Bcl-2 protein, a negative regulator of apoptosis, in MM as compared with benign nevi. It is hypothesized that other apoptosis regulators may be involved in survival of MM cells. We examined the expression of Bax, Bcl-2, Bcl-X, and Mcl-1 in human benign nevi, primary MM, and metastatic MM using immunohistochemistry. Results were confirmed with Western blotting. The proapoptotic protein, Bax, was surprisingly overexpressed in all MM samples compared with benign nevi. Interestingly, in most MM samples there was overexpression of Mcl-1 or Bcl-XL, both negative regulators of apoptosis. Increased expression of Mcl-1 and Bcl-XL was first observed in thin primary melanomas, suggesting that up-regulation of these proteins represents a relatively early event associated with malignant transformation in MM. As published previously, the majority of primary and metastatic MM exhibited reduced Bcl-2 levels. We conclude that the apoptosis inhibitors Bcl-XL or Mcl-1, alone or in combination, may circumvent the normal cell death pathway, contributing to the pathogenesis and treatment resistance in metastatic MM.

p53-dependent apoptosis in melanoma cells after treatment with camptothecin.

Cutaneous malignant melanoma is a life-threatening cancer with poor prognosis due to a high metastasis potential. The main obstacle in treatment of metastatic melanoma is the resistance to chemotherapy. Recent studies indicated that apoptosis is a common mechanism of action for various cytotoxic agents. As p53 plays an important part in apoptosis, we investigated the role of p53 in chemosensitivity of melanoma cells. Previously, we found that melanoma cell lines containing wild-type p53 have significantly higher response rates to chemotherapy than cell lines with a mutant p53 gene. To confirm the role of p53 in melanoma chemosensitivity further, we transfected an expression vector, pED1, which carries a mutant p53 gene, into a wild-type p53 melanoma cell line, MMAN. We examined the effect of mutant p53 on camptothecin-induced apoptosis and the expression of genes which are known to be involved in apoptosis or drug resistance, such as bcl-2, bax, bak, p21waf1, and P-glycoprotein. Our results indicate that overexpression of the mutant p53 increased the growth rate of MMAN cells, reduced the sensitivity to camptothecin, and lowered drug-induced apoptosis by 2-3-fold. Flow cytometry indicated that the camptothecin-induced apoptosis is not associated with G1 arrest. Furthermore, camptothecin treatment reduced bcl-2 and P-glycoprotein expression in wild-type p53 MMAN cells, but not cells overexpressing mutant p53. These results demonstrate that p53 mutational status is a determinant of melanoma chemosensitivity. p53 may downregulate bcl-2 and P-glycoprotein to induce apoptosis in melanoma cells after chemotherapy.

Genotypic analysis of T-cell clones derived from cutaneous T-cell lymphoma lesions demonstrates selective growth of tumor-infiltrating lymphocytes.

The nature of T cells contained within cutaneous lesions of cutaneous T-cell lymphoma (CTCL) has not been studied at the clonal level. T cells extracted from skin lesions of two CTCL patients were cloned by limiting dilution and propagated in interleukin-2 (IL-2) containing medium with periodic lectin stimulation. Twelve T-cell clones were derived from each patient. In both cases, genotypic analysis of the T-cell clones revealed that these clones had T-cell receptor (TCR) beta- and gamma-chain gene rearrangements distinct from the predominant, presumably malignant, clone present in the skin, lymph nodes, or blood. This suggests that they were derived from presumably reactive (non-malignant) T cells. Furthermore, these clones had gene rearrangements different from each other, indicating their multiple clonal origins. The failure to propagate in vitro the CTCL T-cell clone suggests that CTCL cells may have growth requirements different from normal T cells. Thus, conventional T-cell culturing methods using IL-2 and lectins as mitogen may selectively propagate the presumably reactive T cells contained within the skin lesions. The ability to selectively grow these reactive lesional T cells (so-called tumor infiltrating lymphocytes) raises the possibility that these cells could be used in adoptive immunotherapy.

Leukemic T cells from patients with cutaneous T-cell lymphoma demonstrate enhanced activation through CDw60, CD2, and CD28 relative to activation through the T-cell antigen receptor complex.

Antigen-dependent activation of T cells occurs through the T-cell antigen-receptor complex (TCR/CD3). Antigen-independent T-cell activation may occur through the surface molecules CDw60, CD2, and CD28. We wished to determine whether these antigen-independent T-cell-activation pathways could be involved in proliferation of leukemic T cells from patients with cutaneous T-cell lymphoma (CTCL). Whereas CDw60 was only expressed on 28% +/- 7% (mean +/- SEM) of blood T cells obtained from healthy control subjects (n = 4), CDw60 was expressed on 94% +/- 3% of blood T cells obtained from patients with CTCL (n = 4). Dual color immunofluorescence microscopy of the T-cell infiltrate in involved skin of these patients demonstrated that almost 100% of the T cells expressed CDw60. Not only did T cells in the patients with CTCL express CDw60, but triggering of the T cells with anti-CDw60 resulted in enhanced proliferation relative to anti-TCR/CD3 and mitogenic lectins. Other antigen-independent pathways also appeared highly active in the T cells from patients with CTCL because enhanced proliferation relative to anti-TCR/CD3 or mitogenic lectins was found when anti-CD2 or anti-CD28 plus phorbol ester was used as stimulant. Despite the brisk proliferation induced by anti-CDw60, anti-CD2, or anti-CD28, T cells from the patients did not produce detectable amounts of gamma-interferon. The inability to produce gamma-interferon correlates with our finding of absent (n = 3) or weak (n = 1) intercellular adhesion molecule-1 expression in the lesional keratinocytes in these patients. In conclusion, T cells of patients with CTCL demonstrate elevated expression of a T-cell-independent signaling molecule CDw60 and respond to antigen-independent activating signals.

Cyclosporine in the treatment of psoriatic arthritis.

The short-term efficacy of cyclosporine in the treatment of six patients with moderately severe to severe psoriatic arthritis was evaluated in an open study. Patients received oral cyclosporine (6 mg/kg/d) for eight weeks. In all patients, significant improvement of psoriasis was noted within two to four weeks. At the end of therapy, rheumatologic assessment revealed the following trends in disease activity: a decrease in the number of tender joints, joint tenderness index, duration of morning stiffness, and an increase in grip strength. There was a decrease in the number of swollen joints, joint swelling index, and the time taken to walk 50 ft. Overall disease activity significantly improved as assessed independently by the patient and physician. For psoriasis and psoriatic arthritis, disease activity worsened toward baseline within four weeks of discontinuation of therapy. Short-term, low-dose cyclosporine therapy may be effective in treating psoriasis and psoriatic arthritis.

Cyclosporine in lamellar ichthyosis.

In an open trial, five patients with lamellar ichthyosis showed no response to four weeks of treatment with oral cyclosporine (cyclosporine A) (6 mg/kg/d). Histologic examination of lamellar ichthyosis revealed hyperkeratosis; psoriasiform acanthosis; dilated, tortuous capillaries; and a slight perivascular lymphocytic infiltrate. Immunofluorescence studies revealed, in the epidermis, normal numbers of T6+DR+ Langerhans' cells and an absence of T cells and intercellular adhesion molecule-1 expression. In the papillary dermis, there were prominent capillaries as detected by staining with anti-factor VIII-related antigen. The endothelial cells also expressed large amounts of HLA-DR and intercellular adhesion molecule-1, suggesting that they were activated. Only occasional Langerhans' cells were found in the dermis. Histologic and immunofluorescence findings were unchanged with cyclosporine therapy. The effects of cyclosporine on lamellar ichthyosis are contrasted with those reported for psoriasis. Since lamellar ichthyosis and psoriasis share similar features of epidermal hyperproliferation and the presence of activated, dilated, tortuous vessels, but differ in the lack of immunologic cellular activity, their contrasting response to cyclosporine suggests that the target of the action of cyclosporine is the immune system rather than the keratinocyte or the endothelium. However, other factors may have to be considered.

Abnormal function of CD4+ helper/inducer T lymphocytes in a patient with widespread human papillomavirus type 3-related infection.

Human papillomavirus-induced infections may be associated with cellular immunodeficiency. However, very little is known about the dysfunctional interactions among T lymphocytes, B lymphocytes, and antigen-presenting cells. A 30-year-old heterosexual man with a 10-year history of persistent multiple refractory flat wart lesions containing human papillomavirus type 3-related DNA sequence was studied. The patient had a severe depletion of CD4+ T lymphocytes and a compensatory increase in the number of CD8+ T lymphocytes. Impaired T-lymphocyte response to various stimuli was found. Depletion of the increased number of CD8+ T lymphocytes, which suppressed immunoglobulin production in vitro, did not restore the impaired T-lymphocyte response. Immobilized anti-CD3 beads that stimulate the T lymphocyte antigen complex in the absence of antigen-presenting cells indicated a T-lymphocyte defect, rather than a decreased antigen-presenting cell function. Thus, the pronounced cellular immunodeficiency was due to abnormal function of the CD4+ helper/inducer T lymphocytes.

Oral cyclosporine in the treatment of inflammatory and noninflammatory dermatoses. A clinical and immunopathologic analysis.

Cyclosporine is known to be effective in the treatment of psoriasis. In this study, we have used oral cyclosporine (6 mg/kg per day) given for 5 to 30 weeks to 24 patients for the treatment of 12 different dermatoses. Patients with the following diseases demonstrated a marked response or total clearing: 1 patient each with pyoderma gangrenosum, pityriasis lichenoides chronica, and psoriasis of the acrodermatitis continua of Hallopeau type. Moderate to marked response occurred in both patients with epidermolysis bullosa acquisita and the patient with hidradenitis suppurativa. Minimal to moderate responses were obtained in both patients with granuloma annulare, 1 of 2 with acrodermatitis continua of Hallopeau, both patients with Darier's disease, and 1 of 6 patients with vitiligo. Little or no response was noted in both patients with sarcoidosis, all 3 patients with pityriasis rubra pilaris, 5 of 6 patients with vitiligo, 1 patient with pemphigus foliaceous, and 1 with pemphigus vulgaris. Clinical side effects were mild and transient and included dysesthesia, fatigue, hypertrichosis, nausea, and flushing. The most frequent clinically significant abnormalities were hypertension and renal dysfunction, with all factors normalizing within 1 month of discontinuation of cyclosporine therapy.

Effect of N-acetylcysteine on UVB-induced apoptosis and DNA repair in human and mouse keratinocytes.

The incidence of skin cancer is increasing rapidly, particularly in the Caucasian population. Epidemiological and experimental studies demonstrated that ultraviolet radiation (UVR) is the primary cause for the increasing incidence of skin cancer. It is well known that UV irradiation induces DNA damage. If the damage is not repaired or removed in time, it can lead to mutations and skin carcinogenesis. N-acetylcysteine (NAC) has been shown to be an effective protector against UVB-induced immunosuppression and to modulate the expression of some oncogenes and tumor suppressor genes. To test further the protective effect of NAC against UVR, we used both in vitro and in vivo models to investigate the effect of NAC on UVB-induced apoptosis and repair of DNA damage in human and mouse keratinocytes. Our data indicate that the intracellular glutathione level was increased after treatment with NAC at 10-20 mM but decreased with 40 mM NAC treatment due to the toxicity. At concentrations up to 20 mM NAC did not have a significant effect on UVB-induced apoptosis of cultured human keratinocytes. In addition, in an in vivo mouse model, topical application of NAC (3 mumol cm-2) that has been shown to inhibit UVB-induced immunosuppression did not have any effect on UVB-induced apoptosis and did not reduce the formation or enhance the repair of UVB-induced cyclobutane pyrimidine dimers and (6-4) photoproducts. Our results indicate that NAC is ineffective in preserving the genomic stability of keratinocytes against UVB irradiation.

Expression of cell cycle regulators in human cutaneous malignant melanoma.

We postulate that genes involved in the control of cell proliferation are important determinants of melanoma growth and/or transformation. Using Western blot analysis, we compared the expression of nine key cell cycle regulators in metastatic melanomas with that in benign acquired naevi. Among the cyclin-dependent kinases (CDKs) examined, CDK2 was consistently and significantly overexpressed (three- to eight-fold) in metastatic melanomas compared with naevi. CDK1 and CDK4 exhibited no significant difference in expression between benign naevi and metastatic melanomas. CDK6 expression was variable, with four out of 10 metastatic melanomas showing higher expression than naevi. All the cyclins examined, especially cyclins A and D, were expressed more in metastatic melanomas than in naevi. Cyclin E was not detected in benign naevi, but was easily detectable in most of the metastatic melanomas. In addition, there was significantly greater expression of CDC25A, a tyrosine phosphatase that activates CDK kinases, in the metastatic melanomas. Over-expression of CDK2, CDK6, CDC25A and cyclin A was confirmed in melanoma cell lines. These cell cycle regulators may play an important role in melanoma growth and/or transformation.

Immunosuppressive agents in dermatology. An update.

Azathioprine, cyclophosphamide, methotrexate, and cyclosporine are the immunosuppressive agents most commonly used by dermatologists. Azathioprine has a relatively good safety profile and is therefore often preferred for the treatment of chronic eczematous dermatitides and bullous disorders. Awareness of the role of genetic polymorphisms in its metabolism can increase the efficacy and safety of this drug. Cyclophosphamide is an antimetabolite that has a more rapid onset of immunosuppressive effect than azathioprine, but has significant short-term and long-term toxicity. It is of use in fulminant, life-threatening cutaneous disease. Methotrexate is an antimetabolite that has significant anti-inflammatory activity. Despite its hepatotoxicity, its role in inflammatory dermatoses is broadening. Likewise, the role of cyclosporine is being expanded. This drug has potent T-cell inhibitory effects secondary to interference with intracellular signal transduction. Given the evidence for cumulative renal toxicity, it currently has a role in the short-term treatment of refractory psoriasis and atopic dermatitis, as well as in select inflammatory dermatoses. Familiarity with disease-specific clinical efficacy, side-effect profile, and dosage allows the successful and judicious use of these drugs in dermatologic disorders.

Immunosuppressive agents in dermatology.

Azathioprine, cyclophosphamide, and cyclosporine are immunosuppressive agents commonly used by dermatologists. Azathioprine has a good safety profile and is preferred by most dermatologists for the treatment of bullous pemphigoid, cutaneous vasculitides, chronic eczematous dermatitides, and cutaneous manifestations of connective tissue diseases. For more fulminant diseases such as Wegener's granulomatosis, lymphomatoid granulomatosis, severe cases of systemic lupus erythematosus, or pemphigus, cyclophosphamide is more effective and its use is justified even though it is more toxic. Cyclosporine has been shown to be effective in a variety of dermatoses; the most promising results are seen in psoriasis, lichen planus, pyoderma gangrenosum, and chronic eczematous dermatitides. The long-term safety of cyclosporine remains to be determined, and it should be used judiciously with careful evaluation of the risk-benefit ratio in each case. Dermatologists who use immunosuppressive agents should be familiar with their indications, side effects, dosage, and monitoring.

Ascomycins in dermatology.

Ascomycin derivatives represent a novel class of anti-inflammatory macrolactams that are under development for the treatment of skin diseases. The main biological effect of ascomycins is a blockage of the synthesis of both Th1- and Th2-type cytokines in target cells. SDZ ASM 981 is the most advanced ascomycin derivative under development. It has high antiinflammatory activity in animal models of allergic contact dermatitis and does not induce skin atrophy. Topical application of SDZ ASM 981 has been shown to be effective in atopic dermatitis (AD) and allergic contact dermatitis. Clinical studies using semi-occlusive conditions have also shown effectiveness in psoriasis. SDZ ASM 981 holds promise in overcoming the drawbacks of topical corticosteroids and studies are ongoing to further investigate its efficacy and safety in the treatment of inflammatory skin diseases.

Preoperative ketorolac has a preemptive effect for postoperative third molar surgical pain.

There is uncertainty regarding the role of preemptive analgesia in preventing postoperative pain. Most previous studies were of parallel design completed under general anesthesia with many confounding inter-patient's variables. The present study evaluated the efficacy of preemptive ketorolac in a crossover design in patients undergoing bilateral mandibular third molar surgery. This was a double blind, randomized, placebo-controlled study where 34 patients had each of their identical impacted mandibular third molars removed under local anesthesia on two occasions. Each patients acted as their own control; one side was pretreated with intravenous ketorolac 30 mg before surgery followed by placebo injection after surgery, and for the other side, the patient was given placebo injection before surgery and post-treated with intravenous ketorolac 30 mg after surgery. The difference in postoperative pain between pretreated and post-treated side in each patient was assessed by four primary end-points: pain intensity as measured by a 100-mm visual analogue scale hourly for 12 h, time to rescue analgesic, postoperative analgesic consumption, and patient's global assessment. Throughout the 12-h investigation period, patients reported significantly lower pain intensity scores in the ketorolac pretreated sides when compared with the post-treated sides (P = 0.003). Patients also reported a significantly longer time to rescue analgesic (8.9 h versus 6.9 h, P = 0.005), lesser postoperative analgesic consumption (P = 0.007) and better global assessment for the ketorolac pretreated sides (P = 0.01). Pretreatment with intravenous ketorolac has a preemptive effect for postoperative third molar surgery and extended the analgesia by approximately 2 h.

Temporomandibular disorders--an overview.

Temporomandibular disorders (TMD) have been an area of increased clinical and scientific inquiry in dentistry. This is due to increased patient awareness and desire for treatment as well as scientific advances in the fields of epidemiology, neurobiology and diagnostic imaging. This article sets out to introduce this disorder and describes its aetiology and management.

A randomized controlled trial of pimecrolimus cream 1% in adolescents and adults with head and neck atopic dermatitis and intolerant of, or dependent on, topical corticosteroids.

BACKGROUND: There is a need for alternative treatments for atopic dermatitis (AD) of the face and neck as long-term use of topical corticosteroids (TCS) is associated with skin atrophy and telangiectasia and some patients develop allergy, intolerance or other side-effects. OBJECTIVES: This study was designed to assess the efficacy and safety of pimecrolimus cream 1% in patients with AD of the face and neck who are either dependent on, or intolerant of, TCS. METHODS: A 12-week study comprising a 6-week, double-blind, randomized, vehicle-controlled phase was conducted, followed by a 6-week, open-label phase. Two hundred patients aged 12 years or over with mild to moderate head and neck AD, intolerant of, or dependent on, TCS were randomized to either pimecrolimus cream or vehicle cream. The primary efficacy criterion was the facial investigator's global assessment score at 6 weeks. Secondary efficacy criteria were head and neck Eczema Area and Severity Index (EASI), pruritus score and eyelid dermatitis. Facial skin atrophy and telangiectasia were assessed with dermatoscopy. RESULTS: A significantly higher percentage of patients treated with pimecrolimus was cleared or almost cleared of facial AD compared with vehicle (47% vs. 16%, respectively). A statistically significant difference was also seen on head and neck EASI and pruritus score. Significantly more pimecrolimus-treated patients than vehicle-treated patients achieved clearance of eyelid dermatitis (45% vs. 19%, respectively). Among the 77 patients with skin atrophy at baseline, treatment with pimecrolimus was associated with a reversal in skin thinning. Of the 112 patients with telangiectasia at baseline, no statistically significant difference was seen between treatment groups. Adverse events occurred with similar frequency in both groups. CONCLUSION: Pimecrolimus cream 1% is effective in patients with head and neck dermatitis intolerant of, or dependent on, TCS. Reversion of skin atrophy may occur during TCS-free intervals.

Update on the use of ciclosporin in immune-mediated dermatoses.

Immune-mediated dermatoses, such as psoriasis and atopic dermatitis, affect a significant proportion of the population. Although most cases are not life threatening, these diseases can have a profound effect on the sufferer's quality of life and that of their family. Systemic therapy, such as ciclosporin, is often indicated for severe or recalcitrant disease. The efficacy of ciclosporin in the treatment of psoriasis and atopic dermatitis has been established and clinical data also demonstrate its efficacy in treating less common but equally challenging conditions such as pyoderma gangrenosum, lichen planus, autoimmune bullous disease, recalcitrant chronic idiopathic urticaria and chronic dermatitis of the hands and feet. The risk of potential adverse events associated with ciclosporin is greatly reduced if current treatment and monitoring guidelines are followed.