Effects of hypobaric pressure on human skin: Feasibility study for port wine stain laser therapy (Part I)

2005 ◽  
Vol 36 (2) ◽  
pp. 124-129 ◽  
Author(s):  
Guillermo Aguilar ◽  
Lars O. Svaasand ◽  
J. Stuart Nelson
Keyword(s):  
Laser Therapy ◽  
Human Skin ◽  
Feasibility Study ◽  
Port Wine Stain ◽  
Port Wine

scholarly journals Performance evaluation of pulsed photothermal profiling of port wine stain in human skin

2004 ◽  
Vol 75 (6) ◽  
pp. 2048-2055 ◽  
Author(s):  
Bincheng Li ◽  
Boris Majaron ◽  
John A. Viator ◽  
Thomas E. Milner ◽  
J. Stuart Nelson
Keyword(s):  
Performance Evaluation ◽  
Human Skin ◽  
Port Wine Stain ◽  
Port Wine

Acquired Port-Wine Stain in a Pediatric Patient

2006 ◽  
Vol 10 (3) ◽  
pp. 151-153 ◽  
Author(s):  
F. Sule Afsar ◽  
Ragıp Ortac
Keyword(s):  
Literature Review ◽  
Laser Therapy ◽  
Pediatric Patient ◽  
Pediatric Patients ◽  
Sun Exposure ◽  
Vascular Lesions ◽  
Port Wine Stain ◽  
Port Wine ◽  
Left Forearm ◽  
Port Wine Stains

Background: Acquired port-wine stains (PWSs) are vascular lesions that are identical to congenital PWSs morphologically and histopathologically. Objective: Because acquired PWSs are rarely seen in adult and pediatric patients, we present a 9-year-old boy with an acquired PWS on his left forearm. Conclusion: None of the proposed etiologies, such as trauma, chronic sun exposure, or hormonal medication, was applicable to our patient, and a literature review showed us that acquired PWSs give a faster and better response to pulsed dye laser therapy than congenital lesions do.

Imaging of Port Wine Stain Lesions Using a Multi-Sensor Photoacoustic Probe

2004 ◽  
Author(s):  
John S. Viator ◽  
Steven L. Jacques ◽  
Guillermo Aguilar
Keyword(s):  
Human Skin ◽  
Acoustic Waves ◽  
Basal Layer ◽  
Depth Profiling ◽  
Spatial Relationship ◽  
Skin Surface ◽  
Port Wine Stain ◽  
Port Wine ◽  
Nanosecond Pulses ◽  
Visible Reflectance

Successful treatment of port wine stain (PWS) birthmarks in human skin utilizes cryogen spray cooling (CSC) in conjunction with laser treatment. CSC pre-cools the epidermis to protect it from subsequent laser irradiation which raises the temperature of both the epidermis and the deeper PWS. As the epidermal temperature is depressed by cryogen, damage to the skin surface is minimized while the PWS reaches temperatures sufficient to permanently damage the lesion. In order to optimize cooling and laser heating dosages and to properly guide laser therapy, the spatial relationship of epidermal melanin and PWS must be known. Photoacoustic depth profiling of human skin uses low energy, nanosecond pulses of laser light to induce acoustic waves in optically absorbing media, such as blood and melanin. We used a 532 nm Nd:YAG laser to measure total epidermal melanin content in human skin, comparing the results with visible reflectance spectroscopy. Furthermore, we performed numerical simulations of photoacoustic generation in skin, showing that a hemisperical acoustic sensor array could be used to reconstruct the rete pattern of epidermal melanin in the basal layer. Finally, we built a hemispherical probe for use in future experiments for imaging of human skin.

scholarly journals The Pathogenesis of Port Wine Stain and Sturge Weber Syndrome: Complex Interactions between Genetic Alterations and Aberrant MAPK and PI3K Activation

2019 ◽  
Vol 20 (9) ◽  
pp. 2243 ◽  
Author(s):  
Vi Nguyen ◽  
Marcelo Hochman ◽  
Martin C. Mihm ◽  
J. Stuart Nelson ◽  
Wenbin Tan
Keyword(s):  
Endothelial Cells ◽  
Human Skin ◽  
Current Knowledge ◽  
Vascular Malformations ◽  
Genetic Alterations ◽  
Future Research ◽  
Port Wine Stain ◽  
Port Wine ◽  
Weber Syndrome ◽  
Sturge Weber Syndrome

Port wine stain (PWS) is a congenital vascular malformation involving human skin. Approximately 15–20% of children a facial PWS involving the ophthalmic (V1) trigeminal dermatome are at risk for Sturge Weber syndrome (SWS), a neurocutaneous disorder with vascular malformations in the cerebral cortex on the same side of the facial PWS lesions. Recently, evidence has surfaced that advanced our understanding of the pathogenesis of PWS/SWS, including discoveries of somatic genetic mutations (GNAQ, PI3K), MAPK and PI3K aberrant activations, and molecular phenotypes of PWS endothelial cells. In this review, we summarize current knowledge on the etiology and pathology of PWS/SWS based on evidence that the activation of MAPK and/or PI3K contributes to the malformations, as well as potential futuristic treatment approaches targeting these aberrantly dysregulated signaling pathways. Current data support that: (1) PWS is a multifactorial malformation involving the entire physiological structure of human skin; (2) PWS should be pathoanatomically re-defined as “a malformation resulting from differentiation-impaired endothelial cells with a progressive dilatation of immature venule-like vasculatures”; (3) dysregulation of vascular MAPK and/or PI3K signaling during human embryonic development plays a part in the pathogenesis and progression of PWS/SWS; and (4) sporadic low frequency somatic mutations, such as GNAQ, PI3K, work as team players but not as a lone wolf, contributing to the development of vascular phenotypes. We also address many crucial questions yet to be answered in the future research investigations.

scholarly journals In vivo, high-resolution, three-dimensional imaging of port wine stain microvasculature in human skin

2013 ◽  
Vol 45 (10) ◽  
pp. 628-632 ◽  
Author(s):  
Gangjun Liu ◽  
Wangcun Jia ◽  
J. Stuart Nelson ◽  
Zhongping Chen
Keyword(s):  
High Resolution ◽  
Human Skin ◽  
Three Dimensional ◽  
Port Wine Stain ◽  
Port Wine ◽  
Three Dimensional Imaging

Effect of Time-Dependent Boundary Conditions on Epidermal Tissue Damage During Port Wine Stain Laser Surgery

2001 ◽  
Author(s):  
Guillermo Aguilar ◽  
Sergio H. Diaz Valdes ◽  
J. Stuart Nelson ◽  
Enrique J. Lavernia
Keyword(s):  
Boundary Conditions ◽  
Blood Vessels ◽  
Laser Therapy ◽  
Tissue Damage ◽  
Laser Surgery ◽  
Thermal Damage ◽  
Laser Light ◽  
Time Dependent ◽  
Port Wine Stain ◽  
Port Wine

Abstract Port wine stain (PWS) birthmarks are a congenital and progressive vascular malformation of the dermis, involving capillaries, which occurs in approximately 0.7% of children. The objective of laser surgery for this and similar conditions is to cause selective thermal damage, thrombosis, and, eventually, permanent photocoagulation in the PWS vessels. To achieve this, the radiated laser light is set at a specific wavelength, which is highly absorbed by the blood vessels’ hemoglobin (the major chromophore in blood). Unfortunately, the PWS vessels do not absorb all energy radiated — a significant amount is also absorbed by hemoglobin in the ectatic capillaries of the upper dermis. This unwanted absorption causes two problems: firstly, insufficient heat generation within the targeted vessels leads to poor clinical results, and, secondly, there is an increased risk of damage to the overlying epidermis. In current PWS laser therapy, cryogen spray cooling (CSC) is used effectively to cool and protect selectively the epidermis (tens of micrometers thick) prior to the laser pulse, while minimally cooling the blood vessels. The thermal response of the system is characterized by time and/or temperature dependent boundary conditions. However, in many recent studies, the boundary conditions induced by CSC are regarded as constant. In the present work we study the effects of time-dependent boundary conditions on the overall epidermal thermal damage after PWS laser therapy. We use computer models to simulate the laser light distribution, heat diffusion, and tissue damage, and introduce experimentally determined time-dependent boundary conditions measured for custom-made and commercial atomizing nozzles. We show that time-dependent boundary conditions have a significant effect in the optimal laser dose required to induce photocoagulation of PWS blood vessels while preserving the epidermis.

Sign in / Sign up

Export Citation Format

Share Document