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Biomedical subjects

M Lebwohl

Publications and source records attributed to M Lebwohl.

At least 19 recordsLinked to original sources
PubMed1999

Finasteride in the treatment of men with frontal male pattern hair loss.

BACKGROUND: Finasteride, a specific inhibitor of type II 5alpha-reductase, decreases serum and scalp dihydrotestosterone and has been shown to be effective in men with vertex male pattern hair loss. OBJECTIVE: This study evaluated the efficacy of finasteride 1 mg/day in men with frontal (anterior/mid) scalp hair thinning. METHODS: This was a 1-year, double-blind, placebo-controlled study followed by a 1-year open extension. Efficacy was assessed by hair counts (1 cm2 circular area), patient and investigator assessments, and global photographic review. RESULTS: There was a significant increase in hair count in the frontal scalp of finasteride-treated patients (P < .001), as well as significant improvements in patient, investigator, and global photographic assessments. Efficacy was maintained or improved throughout the second year of the study. Finasteride was generally well tolerated. CONCLUSION: In men with hair loss in the anterior/mid area of the scalp, finasteride 1 mg/day slowed hair loss and increased hair growth.

5-alpha Reductase Inhibitors↗
PubMed1999

Interactions between tazarotene and ultraviolet light.

Tazarotene in combination with phototherapy is being used clinically for the treatment of plaque psoriasis. This study investigates the dose of UVB light required to induce minimal erythema and the dose of UVA light required to induce immediate pigment darkening, with and without pretreatment with tazarotene 0.1% gel. The photostability of tazarotene is also assessed. Pretreatment with tazarotene 0.1% gel 3 times per week for 2 weeks before phototherapy significantly reduced the mean minimal erythema dose (MED) for UVB from 56.25 to 42.50 mJ/cm(2) (P <.01), and significantly reduced the mean UVA exposure required to induce immediate pigment darkening from 20.18 to 18.50 J/cm(2) (P <.05). A thin application of tazarotene gel immediately before phototherapy had no significant effect on the mean MED for UVB, whereas a thick application of the gel increased the MED slightly, from 56.25 to 62.50 mJ/cm(2) (P =.1). Tazarotene remained chemically stable when used in conjunction with UVB or UVA phototherapy. To reduce the patient's potential to burn or tan, we recommend initiating UVB phototherapy at 50% to 75% of the MED when it is used in combination with tazarotene. We also recommend initiating PUVA therapy at slightly lower doses than usual. Lower total doses of UVA or UVB may be needed when patients with psoriasis are treated concomitantly with tazarotene.

Adult↗
PubMed1999

Acitretin in combination with UVB or PUVA.

Combination therapy of psoriasis with acitretin and phototherapy (psoralen-ultraviolet A [PUVA] or ultraviolet B [UVB]) offers multiple advantages over use of either modality alone. As monotherapy, acitretin in doses of 50 mg/day is moderately effective, but is associated with numerous side effects. Single modality treatment with UVB or PUVA involves multiple visits over a period of months and is also associated with dose-limiting side effects. When used in combination, lower doses of both modalities can be used more effectively, helping to reduce side effects. In addition, clearing occurs much more quickly, reducing treatment time and number of phototherapy visits. Moreover, patients whose psoriasis does not clear with monotherapy will often achieve significant clearing with the combination of acitretin and phototherapy.

Acitretin↗
PubMed1999

Duration of remission of psoriasis therapies.

The armamentarium of therapies for psoriasis continues to expand with drugs such as tazarotene, calcipotriene, and acitretin approved in recent years. New forms of old treatments such as cyclosporine and anthralin have also been introduced. Frequently, inadequate attention is devoted to duration of remission. The purpose of this article is to examine the duration of remission reported with many therapies currently used for psoriasis. Studies examining duration of remission are included. Among our conclusions were the following: the definitions of remission/relapse used in various studies differ, duration of remission is influenced by the natural history of each patient's disease, among topical monotherapies anthralin and tazarotene appear to induce longer remissions than calcipotriene and corticosteroids, among systemic agents longer remissions occur with etretinate than cyclosporine or methotrexate but compared with the remission rate of phototherapeutic modalities, especially Goeckerman and PUVA therapy, the remission rates are much less.

Humans↗
PubMed1999

Photoinduced dermal pigmentation in patients taking tricyclic antidepressants: histology, electron microscopy, and energy dispersive spectroscopy.

Two patients had been taking long-term tricyclic antidepressant therapy. Each developed a blue to slate-gray hyperpigmentation in sun-exposed areas. On histologic examination there were refractile golden brown granules free in the dermis along collagen bundles. Similar pigment was present in macrophages and along the basement membrane zone. The granules stained for melanin, but not for iron, and were bleached by the permanganate method. Electron microscopy showed varying size and shaped electron-dense granules within lysosomes and free in the dermis, which, in unstained sections, showed a less dense peripheral halo. This peripheral halo was also evident on light microscopy. Energy dispersive spectroscopy showed these granules to be rich in copper and sulfur (elements present in tyrosinase and pheomelanin, respectively). We believe that this represents a drug-melanosome complex, which is most likely caused by chronic photoactivation.

Antidepressive Agents, Tricyclic↗
PubMed1999

Scavenging of hydrogen peroxide and inhibition of ultraviolet light-induced oxidative DNA damage by aqueous extracts from green and black teas.

Aqueous extracts of green and black teas have been shown to inhibit a variety of experimentally induced animal tumors, particularly ultraviolet (UV) B light-induced skin carcinogenesis. In the present study, we compared the effects of different extractable fractions of green and black teas on scavenging hydrogen peroxide (H2O2), and UV irradiation-induced formation of 8-hydroxy 2'-deoxyguanosine (8-OHdG) in vitro. Green and black teas have been extracted by serial chloroform, ethyl acetate and n-butanol, and divided into four subfractions designated as GT1-4 for green tea and BT1-4 for black tea, respectively. The total extracts from green and black teas exhibited a potent scavenging capacity of exogenous H2O2 in a dose-dependent manner. It appeared that the total extracts from black tea scavenged H2O2 more potently than those from green tea. When tested individually, the potency of scavenging H2O2 by green tea subfractions was: GT2 > GT3 > GT1 > GT4, whereas the order of efficacy for black tea was: BT2 > BT3 > BT4 > BT1. In addition, we demonstrated that total fractions of green and black teas substantially inhibited the induction of 8-OHdG in calf thymus by all three portions of UV spectrum (UVA, B and C). Consistent with the capacity of scavenging H2O2, the subfractions from black tea showed a greater inhibition of UV-induced 8-OHdG than those from green tea. At low concentrations, the order of potency of quenching of 8-OHdG by green tea subfractions was: GT2 > GT3 > GT4 > GT1 and the efficacy of all subfractions became similar at high concentrations. All subfractions of the black tea except BT1 strongly inhibited UV-induced 8-OHdG and the order of potency was: BT2 > BT3 > BT4 > BT1. Addition of (-)-epigallocatechin gallate (EGCG), an ingredient of green tea extract, to low concentration of green and black tea extracts substantially enhanced the scavenging of H2O2 and quenching of 8-OHdG, suggesting the important role of EGCG in the antioxidant activities of tea extracts. The potent scavenging of oxygen species and blocking of UV-induced oxidative DNA damage may, at least in part, explain the mechanism(s) by which green/black teas inhibit photocarcinogenesis.

Carcinogenicity Tests↗
PubMed1999

PUVA (8-methoxy-psoralen plus ultraviolet A) induces the formation of 8-hydroxy-2'-deoxyguanosine and DNA fragmentation in calf thymus DNA and human epidermoid carcinoma cells.

The objective of this study is to investigate if 8-methoxy-psoralen (8-MOP) plus ultraviolet A (UVA) radiation (PUVA) induces oxidative DNA damage. When calf thymus DNA was incubated with 8-MOP and irradiated with UVA (335-400 nm), the level of 8-hydroxy-2'-deoxyguanosine (8-OHdG) was substantially increased by approximately 6-fold. Formation of 8-OHdG proportionally correlated with both UVA fluence and 8-MOP concentrations. Human epidermoid carcinoma cells were incubated with 10 microg 8-MOP per milliliter, followed by irradiation of 25 kJ/m2 UVA. The level of 8-OHdG increased by nearly 3-fold in PUVA-treated cells compared to 8-MOP and UVA controls. The formation of 8-OHdG correlated with DNA fragmentation as determined by spectrofluorometry. To investigate the reactive oxygen species (ROS) involved in PUVA-induced oxidative DNA damage, less or more specific ROS quenchers were added to DNA solution prior to PUVA treatment. The results showed that only sodium azide and genistein significantly quenched PUVA-induced 8-OHdG, whereas catalase, superoxide dismutase, and mannitol exhibited no effect. The quencher study with cultured cells indicated that N-acetyl-cysteine and genistein protected oxidative DNA damage as well as DNA fragmentation by PUVA treatment. Our studies show that PUVA treatment is able to induce the formation of 8-OHdG in purified DNA and cultured cells and suggest that singlet oxygen is the principle reactive oxygen species involved in oxidative DNA damage by PUVA treatment.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1999

Erythema nodosum.

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Erythema Nodosum↗
PubMed1998

Benzo[a]pyrene enhances the formation of 8-hydroxy-2'-deoxyguanosine by ultraviolet A radiation in calf thymus DNA and human epidermoid carcinoma cells.

The objective of this study is to investigate if benzo[a]pyrene (BaP) and ultraviolet (UV) radiation synergistically induce oxidative DNA damage. Calf thymus DNA was incubated with BaP and irradiated with UVB (280-320 nm) and UVA (335-400 nm). BaP substantially enhanced the formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) by UVA, but only moderately increased the level of 8-OHdG by UVB. Formation of 8-OHdG proportionally correlated with both UV dose and BaP concentration. Human epidermoid carcinoma cells were incubated with 10 microg of BaP/mL for 24 h and then exposed to 10 kJ/m2 UVB and 25 kJ/m2 UVA. UVB plus BaP did not affect the level of 8-OHdG in cultured cells, whereas UVA plus BaP substantially increased 8-OHdG by over 4-fold compared to BaP and UVA controls. To confirm what reactive oxygen species (ROS) are involved in BaP plus UVA-induced oxidative DNA damage, less or more specific ROS quenchers were added to DNA solution. The results showed that only superoxide dismutase and genistein significantly quenched BaP plus UVA-induced 8-OHdG, whereas catalase, sodium azide, and mannitol exhibited no effect. Our studies suggest that BaP enhances the formation of 8-OHdG in purified DNA and cultured cells by UVA, but not by UVB, and that superoxide anion plays an important role in the synergistic induction of oxidative DNA damage.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1998

Atopic dermatitis.

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Dermatitis, Atopic↗
PubMed1998

DNA structural integrity and base composition affect ultraviolet light-induced oxidative DNA damage.

We previously demonstrated that ultraviolet (UV) light (254 nm) induced the formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in DNA via a singlet oxygen mechanism. In the present paper, we provide novel findings that DNA structure and base composition significantly affect the yield of 8-OHdG by UV radiation. Unlike ionizing radiation that induces 8-OHdG both in free 2'-deoxyguanosine (dG) and in DNA, UV light induced 8-OHdG formation in intact DNA and polydG.dC, but not in dG. When thermally denatured DNA was irradiated with UV light, the yield of 8-OHdG was reduced by more than 80% compared to intact DNA. Oxygenation of the denatured DNA solution did not restore the yield of UV-induced 8-OHdG. Irradiation of DNA with different AT/GC ratios showed that the yield of UV-induced 8-OHdG varied in proportion to the AT content, suggesting that AT base pairs in DNA enhance generation of the oxidizing species and subsequent oxidation of dG. The natural antioxidants genistein, estradiol, protocatechuic acid (PCA), and oleanolic acid (OA) were investigated for their inhibition of UV-induced 8-OHdG. Genistein and estradiol, that intercalate into DNA as shown by a computer modeling, significantly quenched UV-induced 8-OHdG, whereas PCA and OA did not fit into DNA and exhibited weak or no effect. These results suggest that the intercalation of genistein and estradiol into DNA may alter the DNA structural integrity, interrupt the production of oxidizing species, and subsequently reduce the formation of 8-OHdG by UV radiation.

Animals↗