[Argon laser therapy of sebaceous adenoma].
Explore the source record for details and available documents.
Adenoma↗
Biomedical subjects
W Waidelich
Publications and source records attributed to W Waidelich.
Effect of low-power density laser radiation on healing of open skin wounds in rats.
We performed a study to determine whether laser radiation of low-power density would affect the healing of open skin wounds in rats. The wounds were irradiated daily with a helium-neon laser (wavelength, 632.8 nm) and an argon laser (wave-length, 514.5 nm) at a constant power density of 45 mW/sq cm. The rate of wound closure was followed by photographing the wounds in a standardized way. The collagen hydroxyproline concentration in the scar tissue was determined on the 18th postoperative day. Helium-neon laser radiation had a statistically significant stimulating effect on collagen synthesis in the wound, with a maximum effect at an energy density of 4 joules/sq cm. The rate of wound closure was enhanced significantly between the third and 12th postoperative days. The argon laser exposure produced a significant increase in collagen concentration both in irradiated and nonirradiated contralateral wounds. However, an acceleration of the healing rate was not registered in this case. The wound contraction up to the fourth day of the experiment was inhibited under helium-neon and argon laser exposure to 20 joules/sq cm. The described effects were not specific for the laser light. There may be a wavelength-selective influence of coherent light on the metabolic and proliferation processes in wound healing, with the associated problem of the possible carcinogenic effects of laser radiation.
Animals↗
[Physical and biological principles of the use of lasers in dermatology (author's transl)].
A description of the principle of laser is followed by indicating the specific characteristics of laser light. The biological and physical influences of light are mentioned slightly. Using the laser in medicine primarily means to utilize the thermcal effect of radiation. This effect results both from the parameters of irradiation and thermcal and optical characteristics (absorption and diffraction) of the tissue. The possibilities of employing different systems of laser in dermatology - surgical operations, treatment of skin lesions and light-induced wound healing - are discussed.
Biophysical Phenomena↗
[Therapeutic use of lasers in dermatology].
Lasers are used increasingly in dermatology. The use of different laser types for various indications is discussed. Nevi and benign vessel tumors, tattoos, condylomata acuminata, hypertrophic scars, and keloids are indications for laser therapy. The application of lasers in the treatment of malignant tumors, such as malignant melanoma or malignant vessel tumors, is discussed. Finally, the stimulating effects of laser light with low energy density on wound healing is mentioned.
Cicatrix↗
[Effects of direct laser radiation on human lymphocytes (author's transl)].
In vitro experiments with human lymphocytes showed that if irradiations with coherent light of a He-Ne-laser were performed an immune suppressor effect is obtained. Using incoherent light of the same wavelength, effects only occur (80% compared to the laser) if the light is linear polarized.
Cell Migration Inhibition↗
Partial transtentorial displacement of the cerebellum and the brain stem in hydrocephalus-a primary condition or a result of treatment?
Two cases of upward displacement of parts of the brain stem and the cerebellum are discussed. In both cases shunts for a hydrocephalus had been operating for a long time (three and a half years in one and seven months in the other). One infant had a meningomyelocele but no complete Arnold-Chiari malformation. The cause of the hydrocephalus in the other case was doubtful, but was thought to be transtentorial displacement of the brain stem and the cerebellum causing traction on the pons and consequent meningeal fibrosis with obstruction of the cisterna pontis. In this case osseous hypoplasia of the posterior fossa was excluded by craniometry, so the upward displacement must have been due to hypoplasia of the tentorium cerebelli and its low attachment to the occiput, bringingg about a narrowing of the infratentorial space. The authors believe the condition to be a primary malformation, and reject the hypothesis of secondary herniation following long standing supratentorial decompression. The concept of a primary malformation is supported by previous descriptions of the condition in cases with spina bifida, Arnold-Chiari malformation, and hydrocephalus without shunting, as well as by other features in the cases which have been recorded.
Age Factors↗