Studies Show Combination Laser Therapy Effective At Clearing Acne, Reducing Oil Production

Posted : Thu, 05 Mar 2009 22:00:23 GMT

SAN FRANCISCO, March 5

AAD-lasertherapy-acne

Dermatologist evaluates the latest laser and light sources approved for treating acne

SAN FRANCISCO, March 5 /PRNewswire-USNewswire/ -- From the removal of childhood birthmarks to skin rejuvenation, laser technology has become a mainstay in dermatology. Now, dermatologists are fine-tuning this technology to safely and effectively treat one of the most common skin conditions that plagues teenagers and adults alike: acne.

Speaking today at the 67th Annual Meeting of the American Academy of Dermatology [AAD] (Academy), dermatologist Macrene Alexiades-Armenakas, MD, PhD, FAAD, assistant clinical professor of dermatology at Yale University School of Medicine in New Haven, Conn., presented scientific data illustrating how photodynamic therapy combined with a long-pulse, pulsed-dye laser and topical 5-aminolevulinic acid provides long-lasting clearance of acne lesions.

"Laser technology has made great inroads in the treatment of acne, which until recently has been treated almost exclusively - and with varying degrees of success - with topical, systemic and hormonal medications," said Dr. Alexiades-Armenakas. "Now, we have solid evidence-based medicine supporting the effectiveness of certain laser therapies as a long-term solution for treating active acne. The key is to distinguish the benefits and limitations of these available technologies and select the most effective treatments for each acne patient."

Photodynamic Therapy with a Photosensitizer
In a preliminary study, Dr. Alexiades-Armenakas examined whether a combination of photodynamic therapy (PDT) with a photosensitizer known as topical 5-aminolevulinic acid (ALA) and activated by long-pulse, pulsed dye laser could safely and effectively clear mild to severe cases of acne. PDT works by using laser or light energy - in this case a pulsed dye laser was used - to activate the ALA, which is a solution that penetrates into the oil glands and is applied to the skin one hour prior to treatment. As it penetrates, ALA binds to the oil glands and sensitizes the cells to light.

The 14 patients treated with ALA PDT received one to six treatments depending on the severity of their acne and continued to use topical medications during and after the study. The control group consisted of four patients who were either treated with conventional therapy (such as systemic or topical medications) or with laser energy but without ALA PDT.

Upon analyzing the data, Dr. Alexiades-Armenakas found that all (100 percent) of the 14 patients in the ALA PDT treatment group experienced complete clearance of their acne. She reported that an average of 2.9 ALA PDT treatments was administered to this patient group and improvement in the acne lesions was visible within one to two weeks after the first treatment. By comparison, none of the four patients in the control group who were treated with either laser energy alone or conventional therapy achieved complete clearance of their acne.

"The first-of-a-kind study found this particular form of photodynamic therapy used in conjunction with topical therapy to be the first such treatment to achieve complete clearance of acne up to 13 months post treatment and a 77 percent clearance rate per treatment. Four subsequent studies conducted by other investigators involving an additional 75 patients demonstrated similar results," said Dr. Alexiades-Armenakas. "Patients also experienced an added benefit of significant improvement in their acne scars, as the pulsed dye laser offers superior penetration to the deeper layers of the skin where scars form."
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Sensitive Nanowire Disease Detectors Made by Yale Scientists

Published: October 10, 2008

New Haven, Conn. — Yale scientists have created nanowire sensors coupled with simple microprocessor electronics that are both sensitive and specific enough to be used for point-of-care (POC) disease detection, according to a report in Nano Letters.

The sensors use activation of immune cells by highly specific antigens — signatures of bacteria, viruses or cancer cells — as the detector. When T cells are activated, they produce acid, and generate a tiny current in the nanowire electronics, signaling the presence of a specific antigen. The system can detect as few as 200 activated cells.

In earlier studies, these researchers demonstrated that the nanowires could detect generalized activation of this small number of T cells. The new report expands that work and shows the nanowires can identify activation from a single specific antigen even when there is substantial background “noise” from a general immune stimulation of other cells.

Describing the sensitivity of the system, senior author Tarek Fahmy, Yale assistant professor of biomedical engineering, said:. “Imagine I am the detector in a room where thousands of unrelated people are talking — and I whisper, ‘Who knows me?’ I am so sensitive that I can hear even a few people saying, ‘I do’ above the crowd noise. In the past, we could detect everyone talking — now we can hear the few above the many.”

According to the authors, this level of sensitivity and specificity is unprecedented in a system that uses no dyes or radioactivity. Beyond its sensitivity, they say, the beauty of this detection system is in its speed — producing results in seconds — and its compatibility with existing CMOS electronics.

“We simply took direction from Mother Nature and used the exquisitely sensitive and flexible detection of the immune system as the detector, and a basic physiological response of immune cells as the reporter,” said postdoctoral fellow and lead author, Eric Stern. “We coupled that with existing CMOS electronics to make it easily usable.”

The authors see a huge potential for the system in POC diagnostic centers in the US and in underdeveloped countries where healthcare facilities and clinics are lacking. He says it could be as simple as an iPod-like device with changeable cards to detect or diagnose disease. Importantly, Stern notes that the system produces no false positives — a necessity for POC testing.

The authors suggest that in a clinic, assays could immediately determine which strain of flu a patient has, whether or not there is an HIV infection, or what strain of tuberculosis or coli bacteria is present. Currently, there are no electronic POC diagnostic devices available for disease detection.

“Instruments this sensitive could also play a role in detection of residual disease after antiviral treatments or chemotherapy,” said Fahmy. “They will help with one of the greatest challenges we face in treatment of disease — knowing if we got rid of all of it.”

The work resulted from collaboration between the laboratories of Fahmy and Mark Reed, the Harold Hodgkinson Professor of Engineering & Applied Science within the Yale Institute for Nanoscience and Quantum Electronics (YINQE). Reed and biomedical engineering graduate student Erin Steenblock [erin.steenblock@yale.edu] are also authors on the study that was funded by the Department of Defense, the National Institutes of Health, the Department of Homeland Security and the National Science Foundation.

Citation: Nano Letters 8(10): 3310-3314 (October 1, 2008)

PRESS CONTACT: Janet Rettig Emanuel [janet.emanuel@yale.edu] 203-432-2157

Source

Nano Lett., 8 (10), 3310–3314, 2008. 10.1021/nl801693k

Web Release Date: September 3, 2008
Copyright © 2008 American Chemical Society

Label-free Electronic Detection of the Antigen-Specific T-Cell Immune Response

Eric Stern,† Erin R. Steenblock,† Mark A. Reed,*‡§ and Tarek M. Fahmy*†∥

Departments of Biomedical Engineering, Electrical Engineering, Applied Physics, and Chemical Engineering, Yale University, 55 Prospect Street, New Haven, Connecticut 06511

Received June 13, 2008

Revised August 1, 2008


Abstract:

Detection of antigen-specific T-cells is critical for diagnostic assessment and design of therapeutic strategies for many disease states. Effective monitoring of these cells requires technologies that assess their numbers as well as functional response. Current detection of antigen-specific T-cells involves flow cytometry and functional assays and requires fluorescently labeled, soluble forms of peptide-loaded major histocompatability complexes (MHC). We demonstrate that nanoscale solid-state complementary metal-oxide-semiconductor (CMOS) technology can be employed to allow direct, label-free electronic detection of antigen-specific T-cell responses within seconds after stimulation. Our approach relies on detection of extracellular acidification arising from a small number of T-cells (as few as ~200), whose activation is induced by triggering the T-cell antigen receptor. We show that T-cell triggering by a nonspecific anti-CD3 stimulus can be detected within 10 s after exposure to the stimulus. In contrast, antigen-specific T-cell responses are slower with response times greater than 40 s after exposure to peptide/MHC agonists. The speed and sensitivity of this technique has the potential to elucidate new understandings of the kinetics of activation-induced T-cell responses. This combined with its ease of integration into conventional electronics potentially enable rapid clinical testing and high-throughput epitope and drug screening.

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