Second-generation 1,550-nm fractional photothermolysis for the treatment of acne scars.

BACKGROUND AND OBJECTIVES: Acne scars affect the entire population, causing significant distress and concern. Previous treatments for acne scars have yielded varying degrees of success and associated side effects. Fractional photothermolysis has been shown to improve scars, including surgical scars, hypopigmented scars, and atrophic acne scars. The newest system has the option of increased fluences for greater depth of penetration and variable treatment coverage. Our aim was to determine the efficacy and safety of the second-generation erbium-doped 1,550-nm fractional photothermolysis laser (1,550-nm Fraxel SR laser, Reliant Technologies Inc.) in the treatment of all types of acne scars and of all severities. STUDY DESIGN/MATERIALS AND METHODS: Twenty-nine patients (20 females and 9 males, ages 15-65 years), Fitzpatrick Skin Types I to V, were treated with two to six treatments with the second-generation erbium-doped 1,550-nm fractional photothermolysis laser at 1-month intervals. Fluences ranged from 35 to 40 mJ/microthermal zone. Treatment levels varied from 7 to 10 and "Advanced Level 1," corresponding to treatment coverage of 20% to 35%. Patients were graded on a 4-point scale by three independent physicians using digital photography. RESULTS: The majority of patients achieved a 50% to 75% improvement in facial and back acne scarring (18 of 29 patients). Five patients had an improvement of greater than 75% in acne scarring, 5 patients had a 25% to 50% improvement in acne scarring, and 1 patient had less than a 25% response to treatment. The patients' degree of satisfaction paralleled the physicians' assessment. Side effects were minimal and no posttreatment pigmentary changes were noted. CONCLUSION: Fractional photothermolysis is a safe and efficacious treatment modality for the treatment of all types of acne scars of all severities. No adverse effects were noted, including in patients with Fitzpatrick Skin Types III to V.

A three-component dicamba O-demethylase from Pseudomonas maltophilia, strain DI-6: gene isolation, characterization, and heterologous expression.

Dicamba O-demethylase is a multicomponent enzyme from Pseudomonas maltophilia, strain DI-6, that catalyzes the conversion of the widely used herbicide dicamba (2-methoxy-3,6-dichlorobenzoic acid) to DCSA (3,6-dichlorosalicylic acid). We recently described the biochemical characteristics of the three components of this enzyme (i.e. reductase(DIC), ferredoxin(DIC), and oxygenase(DIC)) and classified the oxygenase component of dicamba O-demethylase as a member of the Rieske non-heme iron family of oxygenases. In the current study, we used N-terminal and internal amino acid sequence information from the purified proteins to clone the genes that encode dicamba O-demethylase. Two reductase genes (ddmA1 and ddmA2) with predicted amino acid sequences of 408 and 409 residues were identified. The open reading frames encode 43.7- and 43.9-kDa proteins that are 99.3% identical to each other and homologous to members of the FAD-dependent pyridine nucleotide reductase family. The ferredoxin coding sequence (ddmB) specifies an 11.4-kDa protein composed of 105 residues with similarity to the adrenodoxin family of [2Fe-2S] bacterial ferredoxins. The oxygenase gene (ddmC) encodes a 37.3-kDa protein composed of 339 amino acids that is homologous to members of the Phthalate family of Rieske non-heme iron oxygenases that function as monooxygenases. Southern analysis localized the oxygenase gene to a megaplasmid in cells of P. maltophilia. Mixtures of the three highly purified recombinant dicamba O-demethylase components overexpressed in Escherichia coli converted dicamba to DCSA with an efficiency similar to that of the native enzyme, suggesting that all of the components required for optimal enzymatic activity have been identified. Computer modeling suggests that oxygenase(DIC) has strong similarities with the core alphasubunits of naphthalene 1,2-dioxygenase. Nonetheless, the present studies point to dicamba O-demethylase as an enzyme system with its own unique combination of characteristics.