Evaluation of two, commercial, multi-dye, nucleic acid amplification technology tests, for HBV/HCV/HIV-1/HIV-2 and B19V/HAV, for screening blood and plasma for further manufacture.

BACKGROUND: The cobas TaqScreen MPX Test, version 2.0, a multiplex, multi-dye nucleic acid amplification technology (NAT) test from Roche was evaluated by two European Blood Banks, the German Red Cross Blood Donor Service, Frankfurt, Germany and Centro de Hemoterapia y Hemodonación de Castilla y León, Valladolid, Spain. In addition, the cobas TaqScreen DPX Test was evaluated for the simultaneous detection and quantitation of parvovirus B19 and the detection of hepatitis A virus (HAV). STUDY DESIGN AND METHODS: The performances of the two tests were evaluated regarding the analytical sensitivity, the reproducibility of the tests using samples containing low concentrations of each virus and cross-contamination using samples containing high titres of virus. RESULTS: The analytical sensitivity of the MPX Test, version 2.0, obtained by the German Red Cross Blood Donor Service was 1·1, 3·9 and 43·3 IU/ml for HBV, HCV and HIV-1, respectively. The comparable analytical sensitivity at Centro de Hemoterapia y Hemodonación de Castilla y León was 3·5, 17·6 and 50·6 IU/ml for HBV, HCV and HIV-1, respectively. The analytical sensitivity of the DPX test determined by the German Red Cross Blood Donor Service was 0·6 and 3·8 IU/ml for HAV and B19. CONCLUSION: These multiplex and multi-dye blood screening assays represent a flexible NAT screening system for mini-pools between 6 and 96 samples per pool and fulfil all requirements of the European Pharmacopoeia for HCV and B19V testing of plasma for fractionation. The inclusion of a new multi-dye technology means discriminatory assays are no longer required for either test thus improving workflow, turn-around time and minimize the risk of obtaining a reactive result for which the virus cannot be identified.

Histopathologic changes of the eyelid skin following trichloroacetic acid chemical peel.

The use of trichloroacetic acid (TCA) as a periorbital and eyelid peel for skin rejuvenation is gaining significant acceptance among oculoplastic surgeons, dermatologists, and other surgery groups. In spite of the current enthusiasm, there remain potentially serious complications resulting from any periorbital peel. Cases of cicatricial ectropion have been reported in phenol-peeled patients, and lower eyelid ectropion has reportedly occurred in patients undergoing deep eyelid peel in conjunction with a blepharoplasty (1,2). To avoid this complication, it is necessary to better understand the depth of the wound produced by different strengths and combinations of peeling agents applied to living eyelid tissue and, more important, to determine the concentrations of TCA that are likely to lead to cicatricial ectropion when applied in a consistent fashion. We chose upper-eyelid skin because it is easier to obtain for histopathologic study than lower-eyelid skin and, in our experience, is more sensitive to hypertrophic changes after chemical peeling or carbon dioxide laser resurfacing. We applied TCA to the preseptal skin of 10 patients 48 h before standard upper-eyelid blepharoplasty. The acid was applied to produce a "frost," using varying concentrations of acid, ranging from 20 to 50%. The treated skin removed at the time of blepharoplasty was reviewed in a masked fashion by a dermatopathologist to determine the depth of necrosis. We found that superficial peels with necrosis involving 30% of the epidermis were produced by the lowest-concentration combination of TCA applied (20% followed by 0%). As the strength increased, so did the depth of peel. The combination of 50% followed by a second application of 50% produced the deepest peel, with necrosis into the papillary dermis. This finding would indicate that the chance of developing cicatricial ectropion with any of the tested combinations of TCA should be very remote.

A peeler's thoughts on skin improvement with chemical peels and laser resurfacing.

The new pulsed CO2 lasers are an exciting modality. They have the ability to do what no other procedure can do with the same safety profile. The drawbacks of cost, pain and prolonged healing, however, serve to limit the lasers use to a niche, rather than replacing all other means of skin resurfacing. Skin problems of the epidermis and superficial papillary dermis are more easily and less expensively treated with chemical peeling. This includes most types of hyperpigmentation as well as actinic keratoses and poorly textured skin. This is especially true of postinflammatory hyperpigmentation, in which any procedure that creates prolonged erythema dramatically increases the risk of increased pigmentation. In these patients, the use of CO2 laser resurfacing is risky, if not even contraindicated. Skin problems of the deeper papillary dermis and reticular dermis, such as rhytides and scars, however, respond as well to laser resurfacing as they do to deep chemical peels, but with a better safety profile and a more natural clinical appearance of the healed skin. In many cases, the patient would be better served with a medium depth chemical peel of the entire face and laser resurfacing of the rhytides in the perioral or periorbital areas. This would give the patient the best clinical result with the fastest recovery. The major drawback to this type of therapy has been that the postoperative care of the two treatment regions is different. This may cause some logistical difficulties for the patient, as well as some confusion. Certainly, another option is to treat the patient on two separate occasions; that is, first peel the entire face and then later go back and laser resurface the areas of the remaining rhytides. Although this approach creates more healing time for the patient, it minimizes the areas of prolonged erythema, thereby allowing the patient a faster return to normal. As laser technology continues to advance, we can expect faster healing times and less expensive machinery. Presumably, with our current understanding of the wound healing process, we should expect better post laser treatment regimens, with associated faster healing. Therefore, it is distinctly possible that the current niche for pulsed CO2 lasers will be expanded greatly in the next year or two.

A histological comparison of 50% and 70% glycolic acid peels using solutions with various pHs.

BACKGROUND: Seventy percent glycolic acid solutions are being commonly used as superficial chemical peeling agents. The pH of these solutions ranges from 0.08 to 2.75. The histologic effects of these various pH solutions on human skin have not been studied. OBJECTIVE: The histologic effects of several commercially available glycolic acid solutions at various pHs were examined. METHODS: Test areas of seven glycolic acid solutions were applied to facial skin of two patients. The skin was not prepped for a peel prior to the application of the acid. The solution was left in place for 30 minutes, then neutralized. After 48 hours, a 2-mm punch biopsy was performed and examined histologically. RESULTS: The peeling solutions with a pH below 2 demonstrated the potential to induce crusting and necrosis, which was not seen with the partially neutralized solutions with a pH above 2. The higher concentration acids (70%) created more tissue damage than the lower concentration (50%) when comparing solutions with free acid. CONCLUSION: This study demonstrates that chemical peeling with a 70% free glycolic acid creates more tissue damage than a free glycolic acid. When using a 70% glycolic acid solution, the lower pH products (below pH 2) create more necrosis than the partially neutralized products with a pH above 2. At this time there is no evidence that creating necrosis leads to a more favorable result of the peel. Therefore, the use of partially neutralized glycolic acid solutions seems prudent, since they have a better safety profile than low pH solutions, which contain only free glycolic acid.

The efficacy of a topical lidocaine/prilocaine anesthetic gel in 35% trichloroacetic acid peels.

BACKGROUND: A topical formulation of lidocaine and prilocaine has been shown to provide effective anesthesia for certain superficial skin treatments. OBJECTIVE: To evaluate the efficacy of a topical self-occluding gel containing lidocaine 2.5% and prilocaine 3.5% in reducing the discomfort of 35% trichloroacetic acid (TCA) peels. METHODS: Ten patients who had previously undergone 35% TCA peels were treated with this anesthetic gel prior to their second 35% TCA peel. They rated their level of discomfort in comparison with their previous peel with no anesthesia. RESULTS: Eight of 10 patients reported at least a 40% reduction in discomfort. However, there was a tendency for the anesthetic gel to enhance the depth of the peel. CONCLUSION: Topical lidocaine/prilocaine gel is an effective agent for reducing the discomfort associated with 25% TCA peeling. However, it should only be used with TCA below 30% concentrations due to its ability to enhance the depth of the peel.

An overview of alpha hydroxy acids.

Alpha hydroxy acids (AHA), a group of naturally-occurring compounds, have the potential to improve a variety of skin disorders. Understanding the mechanism of action, types of treatment, side effects, and available AHA products will allow the dermatology nurse to better educate patients regarding aesthetic skin therapies.

The clinical use of alpha hydroxy acids.

Alpha Hydroxy Acids are a group of organic acids which have recently become popular in the treatment of several skin conditions. This article explores some of the clinical uses of these products in the treatment of ichthyosis, acne, hyperpigmentation and photo-damage. Specific recommendations are given for the treatment of each condition.

Trichloroacetic acid and other non-phenol peels.

Medium peels are an excellent modality for treating actinically damaged skin. Because they create wounds that extend only down into the upper dermis, they have less risk of complications than deeper phenol peels. Conversely, because of their more superficial nature, they also are not as effective as phenol peels in improving deep scars and wrinkles. Cosmetic surgeons should consider medium-depth peels a useful addition to their current armamentarium against aging skin, rather than a replacement for phenol peels.

Safety parameters for avoiding acute ocular damage from the reflected CO2 (10.6 microns) laser beam.

Reflections from instruments in the surgical field involving the CO2 laser beam present a serious ocular hazard. In addition to the use of plastic or glass protective eyewear, this hazard can be minimized by utilizing anodized instruments and recognizing the specific distances at which various reflections are no longer hazardous depending upon certain variables, including laser output wattage, emergent beam lengths, and surface characteristics of the reflecting instruments.

Pityriasis rotunda: two cases in black Americans.

Pityriasis rotunda is an uncommon cutaneous disorder consisting of asymptomatic, perfectly circular, scaling plaques on the trunk and extremities. Histopathologic findings are consistent with ichthyosis vulgaris. The majority of cases are seen in association with an underlying disease, and most authors believe that this entity represents a form of acquired ichthyosis. Previous cases have been restricted to certain geographic and ethnic groups (most commonly Japanese and South African Bantu). We report two cases of pithyriasis rotunda, both occurring in black Americans. We believe that these are the first reported cases seen in Americans.

Embedded foreign bodies presenting as earlobe keloids.

We present a case report of a young woman who developed earlobe nodules subsequent to the piercing of her ears. Clinically the nodules appeared to be keloids. Surgical intervention demonstrated the nodules to consist of the embedded backings of her pierced earrings.