Objective: A histopathological and immunohistochemical study was initiated to assess changes in benign human pigmented skin lesions after quality switched ruby laser (QSRL) irradiation. Method: A total of 196 solar lentigines on 8 patients’ forearms were irradiated in vivo, 13 biopsies were taken. Hematoxylin-eosin staining and immunohistochemical techniques using anti-S-100 and Fontana-Masson stainings, as well as cryosections stained with nitroblue tetra-zolium chloride (NBTC), were employed for the evaluation of the specimens. Results: Immediately after QSRL impact selective photothermal damage (vacuolization) of all pigmented epidermal and basal melanocytes, keratinocytes, superficial dermal melanocytes and melanophages could be observed in solar lentigines. Cryosections stained with NBTC featured minimal thermal damage of the surrounding tissue. One Becker’s nevus was also exposed to the QSRL, biopsies were taken before and immediately after QSRL exposure. In this lesion, superficially located pigments were selectively damaged, but a fair amount of pigmented cells in adnexal structures persisted throughout this single course of QSRL treatment. Recurrence of lentigines was not observed. In Becker’s nevus, following initial fading of the lesion, clinically reactive hyperpigmentation occurred 4 weeks later. Conclusion: We found that pigmented lesions featuring a moderate amount of pigment exclusively in and around the basal cell layer, like solar (actinic) lentigo, can be successfully removed by a single QSRL exposure selectively damaging epidermal and basal pigmented structures. Further investigations concerning QSRL treatment of dermally pigmented skin lesions have to be initiated.
In the Western world, more than 10% of the population have at least 1 tattoo. If the tattoo is removed, the tattoo pigment particles in the skin can be selectively destroyed by means of selective photothermolysis. This treatment requires laser pulses of short durations (nanoseconds) and high intensities. We report on 12 patients who received treatments with improper treatment parameters. In all patients, we diagnosed hypo- or hyperpigmentations and scar formation at the treatment site. In particular, the pulse duration of the light sources or lasers applied were considerably longer than those required by the principles of selective photothermolysis. The light intensities of those devices are normally not sufficient to destroy the pigment particles. Instead of destruction, the pigment particles in the skin are heated up and the heat is conducted to the adjacent tissue causing unspecific tissue injury. Lasers or intense pulsed light sources with millisecond pulses and low light intensities are clearly not suitable to be applied for tattoo removal.
The values for the maximum coagulation depth (MCD) of various types of lasers which are specified in the literature are not comparable, because often different irradiation times were used. MCD depends not only on the wavelength of laser light, but also on the time of action of the laser beam, because of heat transfer. In excised human skin MCD was determined histologically for irradiation with the argon laser, Nd:YAG laser, and CO2 laser. Extending the irradiation time from 0.2 s to 10 s results in a 4-6-fold increase in MCD. Coagulation experiments performed with a soldering iron have shown results similar to those obtained with the CO2 laser. Enlargement of the laser-beam diameter from 1 to 2 mm leads to a 50% increase in MCD. Additional chilling of the skin with water during laser irradiation protects the skin from evaporation, and the values for MCD increase to 3.5 mm for the argon laser and 5.5 mm for Nd:YAG laser. Detailed knowledge of the MCD is necessary to obtain the desired therapeutic effect, and also to avoid unwanted effects.
The effect of Laser light on the motility and the velocity of human spermatozoa were measured by means of multiple ex osure photography. Total sperm motility increased after Laser irradiation at 4 J/cm', 8 J/cmz and 32 J/cm2 respectively with respect to control. However, no influence on sperm velocity was demonstrated after Laser irradiation. This observation suggests that Laser light stimulates non-motile live spermatozoa. Die Effekte des Laserlichts auf Spermatozoenmotilitat und Spermatozoengeschwindigkeit in vitroSemen samples were obtained by masturbation form normal subjects and from patients
GvHD remains associated with significant morbidity and mortality despite new techniques for allogeneic stem cell transplantation (SCT), such as optimized conditioning regimens. Within the past ten years, the incidence of acute GvHD has remained unchanged and the incidence of chronic GvHD has even increased. The traditional classification of GvHD according to the time of clinical manifestation is now out-dated. Acute GvHD symptoms may even occur after 100 days; vice versa, primary chronic GvHD may already be observed one month after stem cell transplantation. The current classification introduced by the National Institutes of Health includes classic acute GvHD (up to 100 days), late-onset acute GvHD (after 100 days), as well as an overlap syndrome showing features of acute and chronic GvHD and classic chronic GvHD without any time limit. Diagnosis of GvHD of the skin remains difficult because of histological similarities to drug eruptions and viral exanthems. In this first part of the article the pathophysiology, classification, skin manifestations of acute and chronic GvHD and the histopathology will be presented. In a second part the prognosis, prophylaxis and therapy of GvHD will be discussed.
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