title: Epidermal and vascular damage analysis of in vivo human skin in response to 595 nm pulsed laser irradiation.
abstract: OBJECTIVE
  Laser irradiation is the current modality for treatment of cutaneous hypervascular malformations such as port wine stains and telangiectasia. Although cryogen spray cooling (CSC) is used to protect the epidermis from non-specific laser-induced thermal damage in moderately-pigmented skin types, individuals with high melanin content are still at risk for epidermal damage using the current laser irradiation and CSC parameters. The objective of this study was to investigate the influence of the spray Weber number (1,100 or 5,100) on epidermal protection and examine vascular coagulation in response to pulsed dye laser irradiation.
  
  
  METHODS
  Normal, in vivo human skin from eight subjects of Fitzpatrick skin types I-V were precooled with either low or high Weber number cryogen sprays and subsequently irradiated with a pulsed dye laser at 595 nm. Analysis of gross purpura, morphological vascular damage, and apoptosis of the vascular walls were performed.
  
  
  RESULTS
  Results demonstrated a high Weber number spray of 5,100 decreased the level of epidermal damage in darker and moderate pigmented individuals compared to a Weber number spray of 1,100. This study also established a positive correlation between gross purpura and the level of vessel wall apoptosis.
  
  
  CONCLUSIONS
  This study has demonstrated that CSC with a high Weber number spray can decrease nonspecific thermal damage to the epidermis in response to laser irradiation in vivo. We have also established a positive correlation between gross purpura and the level of vessel wall apoptosis. Lasers Surg. Med. (c) 2005 Wiley-Liss, Inc.
authors.affiliation: Department of Bioengineering, Rice University, PO Box 1892, Houston, TX 77251, USA.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Pikkula
authors.forename: David W
authors.initials: DW
authors.lastname: Chang
authors.forename: Tianhong
authors.initials: T
authors.lastname: Dai
authors.forename: Bahman
authors.initials: B
authors.lastname: Anvari
mesh_terms: D000335:Aerosol Propellants / Q000008:administration & dosage; D017209:Apoptosis / Q000528:radiation effects; D001777:Blood Coagulation / Q000528:radiation effects; D001808:Blood Vessels / Q000528:radiation effects*; D017679:Cryotherapy / Q000379:methods*; D004817:Epidermis / Q000187:drug effects* / Q000528:radiation effects*; D005260:Female; D006801:Humans; D007036:Hypothermia, Induced / Q000379:methods; D028022:Low-Level Light Therapy / Q000379:methods*
chemical_list: D000335:Aerosol Propellants