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At least 181 records · Page 10Linked to original sources
PubMed1998

Selective photothermolysis of hair follicles by normal-mode ruby laser treatment.

This study was designed to evaluate the effect of selective photothermolysis on dark pigmented hair follicles treated with a normal-mode ruby laser (694-nm wavelength, pulse duration 0.5 ms, fluence 20 J/cm2, spot size 2 mm). In 15 volunteers, four test areas each were selected. After shaving, the first area was irradiated once, the second twice, the third three times and the fourth served as control area. A punch biopsy was taken from each volunteer immediately after the first laser treatment. Four weeks after the last irradiation, no effect was found in six cases and little effect in another six cases (50-90% regrowth). Hair regrowth of less than 30% was observed in only three cases. Eight weeks after the last session, no effect was found in 11 cases, little effect in 2 cases (10%) and less than 30% regrowth in only 2 cases. Twelve weeks after the last treatment, no difference could be detected between the areas untreated and treated by laser. The laser parameters applied in this study do not result in effective epilation of body hair. In some cases, a delay in growth of several weeks was noticed.

Adult↗
PubMed2002

Recurrent pilonidal sinus treated with epilation using a ruby laser.

BACKGROUND: Surgical treatment of pilonidal sinus disease of the natal cleft has a significant failure rate. Reported here is the case of a 33-year-old man who first presented at the age of 18 with a pilonidal sinus. METHOD: The patient's scar was treated with a ruby laser using a pulse length of 2 ms and energy densities of 6.0-7.2 J/cm(2). Treatment was performed five times at 6-week intervals. RESULT: The sinus healed and has not recurred to date, 6 months after the last treatment. CONCLUSION: It is felt that there may be a future for this treatment, either as primary treatment or as an adjunct to surgery in refractive cases. It could also be useful in preventing the growth of hairs into wounds that have been left open and allowed to granulate.

Adult↗
PubMed2004

Q-switched ruby laser irradiation on spotty pigmentation in the skin of the hairless dog.

OBJECTIVE: To investigate macroscopically and histopathologically the dermatological changes after Q-switched ruby laser (QRL) irradiation with different exposure doses in UVB-induced pigmentation in hairless dogs. METHODS: QRL irradiation with 3.0, 5.0 and 7.0 J/cm(2) was carried out on the UVB-induced spotty pigmentation in the skin of the hairless dog. Gross appearance was observed daily throughout this study. Histopathological examination was performed 1 day before QRL irradiation and 1 and 3 days and 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14 and 16 weeks after QRL irradiation. RESULTS: Immediately after QRL irradiation, spotty pigmentation was removed. One week after QRL irradiation, re-epithelialization started from the margin of the irradiated sites. between 5 and 10 weeks after QRL irradiation, the skin color returned to normal and some portions showed recurrence of hyperpigmentation. Histopathologically, spotty pigmentation had a heavy deposition of melanin granules in the stratum basale, spinosum and corneum. One day after QRL irradiation, the skin showed destruction of melanin granules. Seven days after QRL irradiation, re-epithelialization began from the surroundings of the QRL-irradiated sites and the pilosebaceous units. The delayed process of re-epithelialization was dependent on the incident exposure dose with QRL. The repaired epidermis was devoid of melanin granules. By 5 weeks after QRL irradiation with 3.0 and 5.0 J/cm(2), the stratum basale and spinosum revealed a redistribution of melanin granules. In the sites of recurrent hyperpigmentation, the bases of the remaining hair follicles showed a notable increase in the reproduction of melanin granules. Melanin granules abundantly aggregated in the bottom portion of the nucleus in each epidermal cell. CONCLUSION: These results revealed that hairless dogs were invaluable laboratory animals, which developed spotty pigmentation after successive UVB irradiation. In addition, UVB-induced spotty pigmentation in hairless dogs is useful for investigating the process of depigmentory treatment with QRL irradiation and recurrence of this lesion.

Animals↗
PubMed1966

An electron microscopy study of vitally stained single cells irradiated with a ruby laser microbeam.

An electron microscope study has been made of vitally stained single cells whose cytoplasm has been subjected to a localized ruby laser microbeam. Light and moderate laser absorption (the resultant of stain concentration and laser energy density) produced restricted selective damage of mitochondria in cells stained with Janus green B; heavy laser absorption resulted in mitochondrial damage, as well as in nonselective interaction with other cell structures. With four other basic vital stains, the polysomes, ergastoplasm, mitochondria and other organelles at the irradiated site were uniformly damaged. Unstained cells showed no morphological alterations. With light primary damage (that restricted to the irradiation site), no secondary effects of the incident radiation were observed. With moderate primary damage, however, secondary damage of the mitochondria in the unirradiated cell portions was produced, which was reversible within 4 hr after irradiation. Heavy primary lesions caused severe secondary alteration of all cell structures that was irreversible and cell death occurred within 2 hr. Surviving cells examined 24 hr after light and moderate irradiation could not be distinguished from unirradiated controls. The possible mechanisms involved in the production of laser-induced cellular alterations are discussed.

Animals↗
PubMed1969

Effect of the ruby laser microbeam on mitochondria of KB cells supravitally stained by pinacyanol.

With pinacyanol as the supravital stain, a preferential effect on mitochondria of KB cells was achieved by the irradiation with the ruby laser beam. The observation confirmed the results of other workers using janus green B in the same experimental system. The preferential effect on mitochondria was noted in the area extending 8-10 micro beyond the nonpreferential damage of 4-5 micro in diameter. The opaque material associated with mitochondria possibly represented coagulated protein. The effect involved cristae mitochondriales without severe disarrangement of their structure. The opaque material could be interpreted as the result of direct interaction between mitochondria and the laser beam, even though the mitochondria were noted outside of the previously estimated focal spot size of about 3 micro Within the thickness of 2-4 micro of monolayered cells, larger areas of damage can be accounted for by divergence of the beam which is focused by a microscope objective of very short focal length. A threshold of biologic effectiveness is probably also involved.

Culture Techniques↗
PubMed2005

Five types of olfactory receptor neurons in the strawberry blossom weevil Anthonomus rubi: selective responses to inducible host-plant volatiles.

Plants release hundreds of volatiles that are important in the interaction with herbivorous animals, but which odorants are detected by which species? In this study, single receptor neurons on the antenna of the oligophagous strawberry blossom weevil Anthonomus rubi were screened for sensitivity to naturally produced plant compounds by the use of gas chromatography linked to electrophysiological recordings from single cells. The narrow tuning of the neurons was demonstrated by responses solely to a few structurally related sesquiterpenes, aromatics or monoterpene hydrocarbons out of hundreds of plant constituents tested. We present five olfactory receptor neuron types, identified according to one primary odorant i.e. the compound to which the neurons are most sensitive. These odorants, (-)-germacrene D, (-)-beta-caryophyllene, methyl salicylate, E-beta-ocimene and (3E)-4,8-dimethyl-1,3,7-nonatriene, present in the intact strawberry plant, are induced in higher amounts by weevil feeding. This suggests that these compounds can provide information about the presence of conspecifics. We used protocols especially designed to allow comparison with previously investigated species. Striking similarities, but also differences, are demonstrated between receptor neuron specificity in the strawberry weevil and moths.

Animals↗
PubMed2005

Exogenous gibberellins inhibit coffee (Coffea arabica cv. Rubi) seed germination and cause cell death in the embryo.

The mechanism of inhibition of coffee (Coffea arabica cv. Rubi) seed germination by exogenous gibberellins (GAs) and the requirement of germination for endogenous GA were studied. Exogenous GA(4+7) inhibited coffee seed germination. The response to GA(4+7) showed two sensitivity thresholds: a lower one between 0 and 1 microM and a higher one between 10 and 100 microM. However, radicle protrusion in coffee seed depended on the de novo synthesis of GAs. Endogenous GAs were required for embryo cell elongation and endosperm cap weakening. Incubation of coffee seed in exogenous GA(4+7) led to loss of embryo viability and dead cells were observed by low temperature scanning microscopy only when the endosperm was surrounding the embryo. The results described here indicate that the inhibition of germination by exogenous GAs is caused by factors that are released from the endosperm during or after its weakening, causing cell death in the embryo and leading to inhibition of radicle protrusion.

Cell Death↗
PubMed1992

Treatment of superficial cutaneous pigmented lesions by melanin-specific selective photothermolysis using the Q-switched ruby laser.

The Q-switched ruby laser at 694 nm, a wavelength well absorbed by melanin relative to other optically absorbing structures in skin, causes highly selective destruction of pigment-laden cells. In addition, the 20-nsec pulse duration produced by this laser approximates the thermal relaxation time for melanosomes, thereby confining the energy to the target. This new laser system produces clinically significant fading of superficial cutaneous pigmented lesions in patients, without complications such as hypertrophic scarring or changes in the normal skin pigmentation, often seen with conventional laser systems or other therapeutic methods. In ongoing clinical trials at our facility, excellent results have been obtained for lentigines, café-au-lait macules, nevus spilus, Becker's nevi, and ephelides (freckles), without skin scarring or textural or permanent pigment changes. The purpose of this report is to (1) describe the theoretical considerations that can be understood and used by a nonlaser-oriented practitioner involved in achieving selective removal of superficial cutaneous pigmented lesions, and (2) describe the practical application of the device to the clinical management of patients.

Female↗
PubMed1996

Traumatic tattooing: treatment with the Q-switched ruby laser: a case study.

This case report details the successful treatment of extensive, facial traumatic tattooing in an adult male. The Q-switched ruby laser was utilized. It is demonstrated to be an excellent tool for the treatment of traumatic tattooing. The results achieved are superior to other methods and complications reported with other treatment options are minimized.

Facial Injuries↗
PubMed1998

Hair removal using the long-pulsed ruby laser.

There are a variety of traditional treatments for the removal of unwanted hair. Recently, lasers have been developed to remove hair. The long-pulsed ruby laser uses light at a wavelength of 694 nm with a 3-msec pulse to destroy hair. Seventy-two patients were treated with this laser from one to four times in a variety of areas. Seventy-one patients had an alteration in their hair growth. One patient had no change in her hair pattern. There were no scars and no permanent changes in pigmentation. Laser hair removal is a useful method for the treatment of unwanted facial and body hair.

Female↗
PubMed2000

The temperatures reached and the damage caused to hair follicles by the normal-mode ruby laser when used for depilation.

Although it is proposed that heat is the cause of follicular damage leading to depilation, this has never been proved. This study aims to determine the mode by which depilation is effected and, if heat is the mechanism, what temperatures are reached within treated follicles and if sufficient damage is produced therein. Two excised specimens of hair-bearing skin from 5 patients undergoing facelifts were dissected to reveal the hair bulbs/shafts on the deep surface. They were placed on a jig, and one pulse from a normal-mode ruby laser (NMRL) of 15 J per square centimeter was fired on the epidermal surface. A thermal imaging camera recorded dermal temperature changes on the deep surface in real time. Specimens were then examined histologically for the site and extent of cellular damage by immunohistochemical staining for a protein marker of cell damage (p53). The NMRL targeted hair follicles specifically. The most common follicular temperature increase ranged from 5 to 10 degrees C. In specimens from 1 patient the increase was more than 30 degrees C (p < 0.001). Heat dissipation into interfollicular tissue in all specimens occurred 2 seconds after exposure. Evidence of laser-induced damage to follicle-lining cells was found only in those follicles with damaged hair shafts. The changes were found to a greater depth (to the bulb) and greater extent (beyond the bulge) in those follicles reaching higher temperatures. These findings suggest that the NMRL should produce permanent depilation. The variability between follicles and between patients explains, perhaps, the uneven outcome regarding depilation using the NMRL. Success appears to depend on peak follicular temperatures achieved during laser exposure, which may result from the follicular characteristics of the individual patient.

Body Temperature↗
PubMed1994

Probabilistic laser safety: ocular damage models for Q-switched neodymium and ruby lasers.

International standards for the protection of the eyes from the hazards of laser radiation define a nominal ocular hazard distance as a distance beyond which an individual would not be expected to suffer any adverse biological effects. The nominal ocular hazard distance, and any associated hazard zones, are calculated using a deterministic technique. This technique does not consider the likelihood that an eye will be irradiated, or the probability that if any eye is exposed, then some level of ocular damage will result. An alternative method of hazard assessment, without compromising safety, is to adopt a probabilistic approach in which the ultimate safety criterion is that the expectation of someone receiving ocular damage must be less than some acceptable risk level. An important element in this assessment is an ocular damage model, which predicts the probability with which a laser exposure will cause permanent eye damage. This paper describes a rationale for the use of the minimum ophthalmoscopically visible lesion as a threshold criterion for the development of ocular damage models. A brief review of existing ocular damage threshold data for Q-switched neodymium:YAG and ruby lasers is presented, and ocular damage models for these lasers systems are derived.

Eye Injuries↗
PubMed1984

Grating visual evoked potentials in the evaluation of laser bioeffects: twenty nanosecond foveal ruby exposures.

A series of experiments was performed to determine the parameters necessary to produce immediate measurable changes in the visual system of nonhuman primates after exposure of the fovea to laser radiation. The parameters investigated were stimulus spatial frequency (1.6 and 2.8 c/deg), size of the visual field stimulated (30 and 3.6 degrees), retinal diameter of the laser exposure (50 and 500 micron), and total intraocular energy. Steady-state visual evoked potentials (VEP's) were recorded from cynomolgus monkeys in response to an oscillating grating. Single 20 ns Q-switched ruby laser pulses (694.3 nm) were directed into the fovea of the experimental eye during the pattern stimulation. No immediate effects on the VEP were noted. Strong delayed effects occurred 45 to 120 s postexposure and were characterized by large phase shifts in the response signal as referenced to the stimulus, magnitude decreases, variance increases, and a loss of waveform correlation with pre-exposure baseline signals. These effects persisted for approximately 30 s before the VEP again became normally re-entrained.

Animals↗
PubMed1993

Rapid response of traumatic and medical tattoos to treatment with the Q-switched ruby laser.

Traumatic tattoos can be very difficult to remove. Excision is often not possible because of the extent of the tattoo, and dermabrasion may not be able to reach the area of pigment without significant scarring. Six patients with traumatic (n = 5) or medical (n = 11) tattoos were treated with the Q-switched ruby laser with complete or nearly complete resolution after one to six treatments without cutaneous scarring or permanent pigmentary alteration.

Adolescent↗
PubMed2004

Coherent interactions of terahertz strain solitons and electronic two-level systems in photoexcited ruby.

We observe coherent interactions between an ultrashort, longitudinal acoustic soliton train and the 29-cm(-1) electronic transition in photoexcited ruby. Propagation of the strain pulses over millimeter distance through an excited zone reveals striking behavior of the induced electronic population, which has been explained by impulsive excitation of the two-level systems, combined with the nonlinear properties of the solitons in the resonant medium. This opens up new possibilities for coherent manipulation of ultrashort acoustic pulses by local electronic centers.

Journal Article↗
PubMed1991

Light and electron microscopic analysis of tattoos treated by Q-switched ruby laser.

Short-pulse laser exposures can be used to alter pigmented structures in tissue by selective photothermolysis. Potential mechanisms of human tattoo pigment lightening with Q-switched ruby laser were explored by light and electron microscopy. Significant variation existed between and within tattoos. Electron microscopy of untreated tattoos revealed membrane-bound pigment granules, predominantly within fibroblasts and macrophages, and occasionally in mast cells. These granules contained pigment particles ranging from 2-in diameter. Immediately after exposure, dose-related injury was observed in cells containing pigment. Some pigment particles were smaller and lamellated. At fluences greater than or equal to 3 J/cm2, dermal vacuoles and homogenization of collagen bundles immediately adjacent to extracellular pigment were occasionally observed. A brisk neutrophilic infiltrate was apparent by 24 h. Eleven days later, the pigment was again intracellular. Half of the biopsies at 150 d revealed a mild persistent lymphocytic infiltrate. There was no fibrosis except for one case of clinical scarring. These findings confirm that short-pulse radiation can be used to selectively disrupt cells containing tattoo pigments. The physial alteration of pigment granules, redistribution, and elimination appear to account for clinical lightening of the tattoos.

Biopsy↗
PubMed2003

A giant melanocytic nevus treated with combined use of normal mode ruby laser and Q-switched alexandrite laser.

We report a combination procedure that can improve the effectiveness of laser removal of giant congenital melanocytic nevi (CMN). A 2-year-old girl with a giant CMN was seen in our outpatient clinic. Histological findings showed a compound nevus without any evidence of malignancy or dysplastic changes. The patient was treated with the normal mode ruby laser and Q-switched alexandrite laser. The lesion was significantly improved in color and cosmetic appearance. Partial hypopigmentation and texture changes were observed. Histological findings showed a marked decrease in the number of junctional melanocytes and the nests in the papillary and reticular dermis. The combined laser treatment is an effective method for the treatment of giant CMN, but further study is warranted to follow-up questions of recurrence and malignant change.

Biopsy, Needle↗