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Biomedical subjects

Mark Lebwohl

Publications and source records attributed to Mark Lebwohl.

At least 73 records · Page 4Linked to original sources
PubMed2003

Protective effects of lycopene against ultraviolet B-induced photodamage.

Lycopene, an acyclic hydrocarbon carotenoid found in tomatoes and their products, is a well-established potent antioxidant, and its anticancer properties have been shown in cultured cells and animal models. We investigated the protective effects of two concentrations of topical lycopene against acute ultraviolet B (UVB)-induced photodamage. Application of lycopene dose dependently inhibited UVB-induced ornithine decarboxylase (P < 0.05) and myeloperoxidase (P < 0.05) and significantly reduced bifold skin thickness (P < 0.05). Immunohistochemical staining revealed increased active caspase-3 of apoptotic pathway in the UVB-exposed group compared with the unexposed control. Application of topical lycopene prevented the cleavage of caspase-3. UVB irradiation completely diminished proliferating cell nuclear antigen (PCNA), and the untreated skin maintained positively stained cells throughout the basal epidermis. Topical application of lycopene significantly reversed UVB-induced PCNA inhibition, and normal PCNA staining was restored in the lycopene-treated skin. Our results suggest that topical lycopene is able to exert its protective effects against acute UVB-induced photodamage. Furthermore, it may act as a preventative agent via inhibition of epidermal ornithine decarboxylase activity, reducing inflammatory responses, maintaining normal cell proliferation, and possibly preventing DNA damage as indicated by blocking the necessitating step of apoptosis following UVB injury.

Administration, Topical↗
PubMed2003

The combination of benzo[a]pyrene and ultraviolet A causes an in vivo time-related accumulation of DNA damage in mouse skin.

Polycyclic aromatic hydrocarbons, including benzo[a]pyrene (BaP), are ubiquitous environmental carcinogens. BaP is metabolized in vivo to reactive intermediates that become covalently bound to DNA and form BaP-DNA adducts, an initial event in carcinogenesis. Ultraviolet A (UVA) synergizes with BaP to significantly enhance genetic damage and accelerate carcinogenic processes. This study was initiated to investigate in vivo cellular changes related to carcinogenesis induced by repeated exposures to BaP plus UVA. Simulated chronic exposure to an environmental carcinogen and sunlight was conducted through biweekly topical application of BaP followed 2 h later by UVA exposure over a 10 week period. BaP diol epoxide (BPDE)-DNA adducts were measured in vivo by immunohistochemistry using an anti-BPDE-DNA monoclonal antibody. Oxidative DNA damage was measured by the detection of 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation using high-performance liquid chromatography. Alterations in the cell cycle that were relevant to carcinogenesis were revealed by changes in p53, as identified in vivo using a polyclonal anti-p53 antibody. We found that cells containing BPDE-DNA adducts and nuclear p53 expression significantly increased between 2 and 10 weeks of BaP-UVA treatment, whereas neither BPDE-DNA adducts nor significant changes in p53 were observed in untreated skin. Using regression analysis, oxidative 8-OHdG damage also showed a parallel increase over 2-10 weeks (r = 0.80). These results indicate that genetic damage caused by exposures to BaP plus UVA accumulates with time and increases the potential for inductive events leading to carcinogenesis and tumor formation.

Animals↗
PubMed2003

Validation of expert opinion in identifying comorbidities associated with atopic dermatitis/eczema.

BACKGROUND: The use of expert opinion is widespread in economic studies of healthcare utilisation; however, few studies have attempted to assess the validity of assumptions derived from such sources. OBJECTIVE: To examine the use of such expert opinion in determining comorbidities associated with atopic dermatitis/eczema (AD/E), which were assessed as part of a recent third-party payer cost-of-illness study. DESIGN: To identify the disease-related comorbidities that would represent costs associated with AD/E, physicians on an expert panel were asked individually and then collectively to group all International Classification of Diseases, 9(th) Edition-Clinical Modification (ICD-9-CM) diagnosis codes as 'most likely', 'possibly' or 'definitely not' related to the costs of identifying and treating patients with AD/E. Claims representing $US464 million in payer reimbursements from nearly 125 000 patients with AD/E were identified within two separate claims databases (1997 values). Over 850 ICD-9-CM diagnosis codes were identified in the first-listed position from these claims. For each group of 'most likely', 'possibly' and 'definitely not' related diagnosis codes, prevalence rates were compared within AD/E and non-AD/E populations from the two historical payer claims databases. Adjusted and non-adjusted odds ratios were calculated by comparing prevalence rates between AD/E and non-AD/E patients in the same payer population. RESULTS: The mean prevalence rate of any diagnosis code in the AD/E population was 0.65 +/- 1.82% (SD) with a mean odds ratio of 1.81 +/- 0.96. Comorbidities considered by the expert panel 'most likely' to be associated with AD/E had higher prevalence rates (3.28 +/- 3.63%) and odds ratios (2.14 +/- 1.14). Comorbidities considered to be 'possibly' related to AD/E had prevalence rates and odds ratios of 3.01 +/- 5.06% and 1.84 +/- 0.82, respectively. Comorbidities considered to be 'definitely not' related to AD/E had the lowest prevalence rates (0.45 +/- 1.09%) and odds ratios (1.80 +/- 0.97). CONCLUSIONS: Comparing the result of consensus panels with actual claims histories validated the use of expert opinion in determining comorbidities associated with AD/E. Expert opinion yielded valid results in terms of identifying comorbidities that manifested frequently and disproportionately in the AD/E population. Limited statistical measurements of comorbidities would have been less specific than expert opinion. Future cost-of-illness studies should consider alternative data sources and methodologies to enhance the validity and importance of expert opinion and to corroborate their findings.

Comorbidity↗
PubMed2003

Use and abuse of topical corticosteroids in infections of the skin and related structures.

Topical corticosteroids have improved the management of many inflammatory skin diseases, such as psoriasis and atopic dermatitis. However, these medications are associated with certain adverse effects that are potentially serious. The potent anti-inflammatory actions of these drugs increase susceptibility to bacterial and fungal infections, and therefore may preclude them from use when infection is the known cause of the disease. In addition, children may be more vulnerable than adults to systemic effects of topical corticosteroids because percutaneous absorption is proportionately greater. These are important considerations, and physicians need to weigh and compare the risks and benefits associated with these medications before initiating treatment. This involves an appreciation of which patient populations are at high risk, which skin conditions are incompatible with topical corticosteroid therapy, and which alternative nonsteroidal medications are effective in treating inflammatory skin diseases.

Administration, Topical↗
PubMed2002

Inhibition of ultraviolet light-induced oxidative events in the skin and internal organs of hairless mice by isoflavone genistein.

We have previously demonstrated that soybean isoflavone genistein inhibits ultraviolet-B (UVB)-induced skin tumorigenesis in hairless mice. In the present study, we further investigated the possible mechanism(s) of action whereby genistein inhibits photocarcinogenesis with focuses on UVB-induced oxidative events, including hydrogen peroxide (H(2)O(2)) production, lipid peroxidation (as represented by malondialdehyde, MDA), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation in vivo. We demonstrated that subacute exposure to UVB substantially increased the level of H(2)O(2), lipid peroxides, and 8-OHdG in skin of hairless mice. In addition, chronic exposure to low-dose UVB (0.9-1.2 kJ/m(2) for 20 weeks) substantially increased the levels of 8-OHdG not only in the epidermis, but also in the internal organs such as liver, brain, and spleen of mice with exception of kidney. However, genistein did not affect the level of UVB-induced pyrimidine dimmers in the same UVB exposed mouse skin, indicating selective inhibition of oxidative DNA damage by genistein. Induction of H(2)O(2) was independent of UVB fluences whereas the levels of MDA and 8-OHdG were induced in an UVB fluence-dependent manner. The results suggest that H(2)O(2) be generated as an acute cutaneous response to UVB irradiation, while MDA and 8-OHdG are accumulated with increasing UVB exposure and more closely related to chronic effects of UVB radiation. Pre-treatment of animals with 10 micromol of genistein 1 h prior to UVB exposure significantly inhibited UVB-induced H(2)O(2) and MDA in skin and 8-OHdG in epidermis as well as internal organs. Suppression of 8-OHdG formation by genistein has been corroborated in purified DNA irradiated with UVA and B. In summary, our results suggest that UVB irradiation elicit a series of oxidative events, which can be substantially inhibited by isoflavonoid genistein through either direct quenching of reactive oxygen species or indirect antiinflammatory effects. Thus, the antioxidative properties of genistein may explain for the mechanisms of anti-photocarcinogenic action of genistein.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2002

Successful treatment of acne vulgaris using a new method: results of a randomized vehicle-controlled trial of short-contact therapy with 0.1% tazarotene gel.

CONTEXT: Short-contact application of 0.1% tazarotene gel for acne was devised to minimize local adverse effects. Its efficacy and safety are unknown. OBJECTIVES: To assess acne improvement and tolerability during 12 weeks of short-contact treatment with 0.1% tazarotene gel vs a nonmedicated gel control. DESIGN: A randomized, masked, vehicle-controlled trial. SETTING: Outpatient facilities at an urban medical school and an affiliated suburban office practice. PARTICIPANTS: Ninety-nine volunteers with facial acne were enrolled; 81 completed the study. INTERVENTION: Thirty-three patients were randomly assigned to each of 3 groups: T + T applied 0.1% tazarotene gel twice daily, T + V applied 0.1% tazarotene gel once daily and vehicle gel once daily, and V + V applied vehicle gel twice daily. Patients adjusted the contact period as tolerated, between 30 seconds and 5 minutes per application. MAIN OUTCOME MEASURES: Acne efficacy by reduction in acne lesions, treatment success (50%-100% improvement in global response to treatment) and improvement in overall disease severity. Local adverse effects, scored from none to severe. RESULTS: By week 12, T + T and T + V achieved significantly greater improvement in acne than V + V based on mean percentage reduction in noninflammatory lesions (46% and 41% vs 2%; P =.002) and inflammatory lesions (38% and 34% vs 9%; P =.01), percentage of treatment successes (64% and 61% vs 15%; P<.001), and reduction in overall disease severity (30% and 29% vs 3%; P<.001). Local adverse effects did not differ significantly among the 3 groups after week 4. CONCLUSION: Short-contact 0.1% tazarotene gel therapy is a safe and effective new method of acne treatment.

Acne Vulgaris↗
PubMed2002

A randomized, double-blind, placebo-controlled study of clobetasol propionate 0.05% foam in the treatment of nonscalp psoriasis.

BACKGROUND: Topical corticosteroids are the primary treatment for mild to moderate psoriasis. Foam preparations of corticosteroids offer potential cosmetic and pharmacodynamic advantages over cream and ointment vehicles. A clobetasol propionate foam product is as effective as clobetasol propionate solution in the treatment of scalp psoriasis. AIM: To evaluate the safety and efficacy of clobetasol propionate foam in the treatment of psoriasis involving sites other than the scalp. METHODS: Eighty-one subjects with mild to moderate psoriasis were randomized in a 3 : 1 ratio to receive clobetasol propionate foam vs. placebo foam treatment in this double-blind study of psoriasis involving nonscalp sites. The investigator's and subject's global assessment of the response at week 2 (or at the end of treatment) and at week 4 (follow-up) and the severity of erythema, scaling, and plaque thickness were assessed. Safety was assessed from reported adverse events. RESULTS: After 2 weeks of treatment, there was significantly greater improvement with clobetasol propionate foam compared with placebo foam in both investigator's and subject's global assessment of the response (P < 0.0005). The improvement with clobetasol propionate foam was still present at the 4-week follow-up visit. Adverse effects were generally limited to mild to moderate application site reactions. No subjects withdrew because of adverse events. CONCLUSIONS: Clobetasol propionate foam is more effective than placebo in the treatment of nonscalp psoriasis. Twice-daily applications are well tolerated, compliance exceeds 90%, cosmetic characteristics are acceptable, and the medication may eliminate the need for separate scalp and body prescriptions.

Administration, Topical↗
PubMed2002

Cost of atopic dermatitis and eczema in the United States.

BACKGROUND: Atopic dermatitis/eczema (AD/E) is a common disease. Few studies have attempted to quantify the cost to third-party payers. OBJECTIVE: Our purpose was to identify the annual cost of medical services and prescription drugs for the treatment of AD/E to private insurance and Medicaid payers in the United States. METHODS: We used a retrospective study design employing claims data from 1997 and 1998 from a private insurer and a state Medicaid program to analyze costs incurred. Beneficiaries were considered to have AD/E if they had at least one claim in 1997 with a primary or secondary listing of 1 of 3 diagnosis codes: 691.8, other atopic dermatitis and related conditions; 692.9, contact dermatitis and other eczema when no cause is specified; or 373.3, noninfectious dermatoses of eyelid. Patients who did not meet the diagnosis criteria served as a control group in each payer for comparisons of expenditures with the AD/E group. RESULTS: Disease prevalence was 2.4% (private insurer) to 2.6% (Medicaid) of all eligible beneficiaries, and 3.5% to 4.1% of patients submitted at least one health care claim during the study period. Medicaid-insured patients used outpatient hospital visits and hospitalizations at a greater rate than did privately insured patients; neither used emergency departments extensively. The third-party payer cost of illness for AD/E ranged from $0.9 billion to $3.8 billion when projected across the total number of persons younger than 65 years insured by private insurers and Medicaid in the United States. More than one fourth of all health care costs for patients with AD/E may be attributed to AD/E and co-morbid conditions. CONCLUSIONS: Annual costs of AD/E are similar to those of other diseases such as emphysema, psoriasis, and epilepsy. Patients incur significant costs associated with AD/E and co-morbid conditions.

Cost of Illness↗
PubMed2002

Clinical and histologic response to single-dose treatment of moderate to severe psoriasis with an anti-CD80 monoclonal antibody.

Pathologic T-cell activation is implicated in psoriasis progression. CD80, a costimulatory molecule involved in T-cell activation, likely plays a key role. IDEC-114, an IgG(1) anti-CD80 antibody, was evaluated for safety, pharmacokinetics, and preliminary clinical activity in this open-label, single-dose, dose-escalating study in patients with moderate to severe chronic plaque psoriasis. Twenty-four patients received IDEC-114 (0.05 mg/kg, 0.25 mg/kg, 1 mg/kg, 5 mg/kg, 10 mg/kg, or 15 mg/kg). Psoriasis Area and Severity Index, Physician's Global Psoriasis Assessment, and Psoriasis Severity Scale scores improved in the highest-dose groups. Average plaque thickness and plaque CD3+ and CD8+ T-cell counts decreased in the 10 mg/kg dose group. Adverse events were primarily mild, transient, constitutional symptoms; the most common related events were mild asthenia (29% of patients), chills (25%), and headache (21%). The serum half-life of IDEC-114 was approximately 13 days. A single dose of IDEC-114 appears to be safe and well tolerated and has promising clinical activity in psoriasis.

Adolescent↗
PubMed2002

Imiquimod cream in the treatment of actinic keratoses.

We studied the usefulness of imiquimod cream in the treatment of 3 patients with actinic keratoses. One patient was treated 3 times per week for 4 weeks and had a marked inflammatory response with nearly complete resolution of actinic keratoses. Two subsequent patients were treated in a bilateral paired comparison study. Both patients had similar numbers of actinic keratoses on symmetric areas and treated only one side with imiquimod cream 2 to 3 times per week with frequent rest periods to avoid inflammation. Both experienced marked reductions in actinic keratoses. After 8 weeks, both patients applied imiquimod cream twice per week for 9 months with continued reduction in actinic keratoses on both sides. Treatments were well tolerated. Imiquimod cream appears to be effective in the treatment of actinic keratoses. The main adverse effect is local inflammation, which can be avoided by reducing the frequency of application.

Adjuvants, Immunologic↗
PubMed2002

Effects of the isoflavone 4',5,7-trihydroxyisoflavone (genistein) on psoralen plus ultraviolet A radiation (PUVA)-induced photodamage.

Long-term psoralen plus ultraviolet A radiation (PUVA) therapy is associated with an increased risk of squamous cell carcinoma and malignant melanoma. Genistein (4',5,7-trihydroxyisoflavone), a major isoflavone in soybeans and a specific inhibitor of protein tyrosine kinase, has been shown to inhibit UVB induced skin carcinogenesis in hairless mice. For this study we examined the protective effects of topical genistein on PUVA-induced photodamage. In two separate experiments, genistein in a dimethyl sulfoxide/acetone (1:9) solution was applied to SKH-1 female mice 1 h post 8-methoxy-psoralen dosing and 1 h prior to UVA irradiation. Application of genistein significantly decreased PUVA-induced skin thickening, and greatly diminished cutaneous erythema and ulceration in a dose-dependent manner. Histological examination showed that PUVA treatment of mouse skin induced dramatic inflammatory changes throughout the epidermis; topical genistein prevented these changes without noticeable adverse effects. Cells containing cleaved poly(ADP-ribose) polymerase (PARP) and active caspase-3 were significantly increased in PUVA-treated skin (P < 0.05 and P < 0.0001, respectively) as compared with unexposed control skin. Topical genistein completely inhibited cleavage of PARP and caspase-3. Proliferating cell nuclear antigen (PCNA) positive cells were observed in suprabasal areas of the epidermis and were significantly decreased in PUVA-treated skin compared with both control samples and samples treated with PUVA plus topical genistein (P < 0.005). These results indicate that genistein protects the skin from PUVA-induced photodamage.

Acetone↗
PubMed2002

Vitamin D and topical therapy.

A sequential therapy regimen involving an initial clearing phase of daily applications of calcipotriene 0.005% ointment and halobetasol 0.05% ointment for 2 weeks, followed by halobetasol applied twice daily on weekends and calcipotriene applied twice daily on weekdays, has been shown to be effective in the management of chronic plaque psoriasis. As a clearing regimen, the combined use of halobetasol and calcipotriene for 2 weeks was superior to monotherapy with either agent. Subsequently, the use of halobetasol on weekends and calcipotriene on weekdays allowed 76% of patients to stay in remission for up to 6 months, compared with 40% of patients who applied halobetasol on weekends only and placebo on weekdays. Calcipotriene can be inactivated when mixed with some topical preparations; however, halobetasol propionate 0.05% ointment and cream have been shown to be compatible with calcipotriene for up to 2 weeks. The compatibility of calcipotriene and halobetasol permits the use of these agents together.

Administration, Topical↗
PubMed2002

Treatment of mycosis fungoides with oral bexarotene combined with PUVA.

Bexarotene has recently been approved in the United States and Europe as a single orally administered retinoid for the treatment of cutaneous T-cell lymphoma (CTCL) in patients who are refractory to at least one prior systemic therapy. We describe a 47-year old female with a 4-year history of mycosis fungoides (MF) who developed debilitating side effects from acitretin and PUVA, and subsequently responded to bexarotene 75 mg orally once daily combined with PUVA. Bexarotene has been approved at an optimal starting dose of 300 mg/m2/d but has not yet been approved for use in combination with PUVA. We used a low dose (75 mg) combined with PUVA in an attempt to minimize side effects while maintaining treatment efficacy. Our patient's response to a novel regimen of low dose bexarotene combined with PUVA has been excellent and suggests that this regimen may be a useful method for treatment of MF.

Anticarcinogenic Agents↗