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At least 127 records · Page 7Linked to original sources
PubMed1996

Q-switched ruby laser treatment of oculodermal melanosis (nevus of Ota).

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- to 40-ns pulse duration produced by this laser approximates the thermal relaxation time for the melanosomes, thereby confining the energy to the target. The Q-switched ruby laser was used to treat 47 patients (11 males and 36 females) with nevus of Ota during the period December 1991 to 1994. The involved facial area ranged from 3 x 3 cm2 to 20 x 20 cm2. The energy fluence used varied from 8 to 10 J/cm2, and the number of treatments ranged from 1 to 8 (mean 3.4). The results were graded on the basis of cleaning and fading as follows: poor (0 to 25 percent), fair (26 to 50 percent), good (51 to 75 percent), and excellent (76 to 100 percent). The mean follow-up period was 15 months. Poor and/or fair results were found in 8 patients who received one treatment and 7 patients who had two treatments. Good results were seen in 1 patient who had two treatments, 7 patients who received three treatments, and 3 patients who had four treatments. Twenty-one patients had excellent results after three or more treatments of the whole lesion. In conclusion, this laser system produces clinically significant fading of nevus of Ota in patients without complications such as hypertrophic scarring or permanent changes in the normal skin pigmentation.

Adolescent↗
PubMed1999

Ruby laser-assisted hair removal success in relation to anatomic factors and melanin content of hair follicles.

Ruby laser-assisted hair removal is thought to work via selective photothermolysis, which relies on light reaching the deeper layers of skin, and the absorption of light by the target chromophore, melanin. It is therefore possible that efficacy of treatment is affected by anatomic factors that determine the amount of light reaching the hair bulbs (i.e., skin color, depth of intracutaneous hair, epidermal thickness and dermal density) and the melanin content of hair. To examine this hypothesis, a prospective study was performed. Forty-eight volunteers were treated with the Chromos 694 Depilation Ruby Laser at a single standard fluence of 11 J/cm2. Treatment efficacy was determined by measuring hair density at 3 and 7 months after treatment. Epidermal depth and dermal density were measured from 2-mm biopsies taken before treatment, and the intracutaneous hair length was determined from plucked hair. Skin color was assessed using a spectrophotometer, and melanin content of dissolved hair was assessed using spectrophotometry. Efficacy of treatment for each patient was compared with the patient's age, intracutaneous hair length, epidermal depth, dermal density, skin color, and total melanin content and relative eumelanin content of hair. No correlation was found between the efficacy of treatment and age and the various anatomic factors. Patients with higher eumelanin content in their hair had better long-term results (Spearman rank test, p = 0.00219). The results suggested that the efficacy of treatment did not depend solely on the amount of laser light penetrating the skin but correlated well with the eumelanin content of hair. The clinical implication of this finding is discussed.

Adolescent↗
PubMed2002

The long-term results of ruby laser depilation in a consecutive series of 346 patients.

The goal of this study was to prospectively assess the long-term results of ruby laser depilation in 346 consecutive patients who underwent hair removal at 402 anatomical sites. The patients were treated using a ruby laser, with mean power ranging from 8.6 J to 15.7 J according to skin type. Results were assessed using two outcome measures-the percentage reduction in hair density and the hair-free interval. The median reduction in hair density was 55 percent (range, 0 to 100 percent) at a median time of 1 year after the last treatment session. The median hair-free interval was 8 weeks. Patients underwent a median number of four treatment sessions. Forty-three of the 346 patients were treated at more than one anatomical site. Of the sites treated, 75 percent reduction in hair density was achieved in 22 percent, 90 percent reduction was achieved in 2.2 percent, and complete depilation was achieved in only 0.7 percent. Darker colored hair was more effectively treated. Treatment efficacy was not affected by anatomical site, with the exception of the faces of male patients, which were found to be particularly resistant to treatment. There was a significant correlation between the number of treatments given and the outcome. The overall complication rate was 9.0 percent (36 of 402 sites) with respect to pigmentary changes and blistering, but varied according to Fitzpatrick skin type. The complication rate was highest in skin types V and VI (24.7 percent), with no complications in skin type I. Although a greater than 50 percent reduction in hair density was achieved in half of the 346 patients treated, complete depilation was achieved in only an extremely limited number of patients.

Adult↗
PubMed2001

A revision of Rhizobium Frank 1889, with an emended description of the genus, and the inclusion of all species of Agrobacterium Conn 1942 and Allorhizobium undicola de Lajudie et al. 1998 as new combinations: Rhizobium radiobacter, R. rhizogenes, R. rubi, R. undicola and R. vitis.

Rhizobium, Agrobacterium and Allorhizobium are genera within the bacterial family Rhizobiaceae, together with Sinorhizobium. The species of Agrobacterium, Agrobacterium tumefaciens (syn. Agrobacterium radiobacter), Agrobacterium rhizogenes, Agrobacterium rubi and Agrobacterium vitis, together with Allorhizobium undicola, form a monophyletic group with all Rhizobium species, based on comparative 16S rDNA analyses. Agrobacterium is an artificial genus comprising plant-pathogenic species. The monophyletic nature of Agrobacterium, Allorhizobium and Rhizobium and their common phenotypic generic circumscription support their amalgamation into a single genus, Rhizobium. Agrobacterium tumefaciens was conserved as the type species of Agrobacterium, but the epithet radiobacter would take precedence as Rhizobium radiobacter in the revised genus. The proposed new combinations are Rhizobium radiobacter, Rhizobium rhizogenes, Rhizobium rubi, Rhizobium undicola and Rhizobium vitis.

Base Composition↗
PubMed2003

Observation of ultraslow light propagation in a ruby crystal at room temperature.

We have observed slow light propagation with a group velocity as low as 57.5+/-0.5 m/s at room temperature in a ruby crystal. A quantum coherence effect, coherent population oscillations, produces a very narrow spectral "hole" in the homogeneously broadened absorption profile of ruby. The resulting rapid spectral variation of the refractive index leads to a large value of the group index. We observe slow light propagation both for Gaussian-shaped light pulses and for amplitude modulated optical beams in a system that is much simpler than those previously used for generating slow light.

Journal Article↗
PubMed1987

Melanosomes are a primary target of Q-switched ruby laser irradiation in guinea pig skin.

The specific targeting of melanosomes may allow for laser therapy of pigmented cutaneous lesions. The mechanism of selective destruction of pigmented cells by various lasers, however, has not been fully clarified. Black, brown, and albino guinea pigs were exposed to optical pulses at various radiant exposure doses from a Q-switched, 40 nsec, 694 nm ruby laser. Biopsies were analyzed by light and electron microscopy (EM). Albino animals failed to develop clinical or microscopic evidence of cutaneous injury after irradiation. In both black and brown animals, the clinical threshold for gross change was 0.4 J/cm2, which produced an ash-white spot. By light microscopy, alterations appeared at 0.3 J/cm2 and included separation at the dermoepidermal junction, and the formation of vacuolated epidermal cells with a peripheral cytoplasmic condensation of pigment. By EM, enlarged melanosomes with a central lucent zone were observed within affected epidermal cells at 0.3 J/cm2. At 0.8 and 1.2 J/cm2, individual melanosomes were more intensely damaged and disruption of melanosomes deep in the hair papillae was observed. Dermal-epidermal blisters were formed precisely at the lamina lucida, leaving basal cell membranes and hemidesmosomes intact. Possible mechanisms for melanosomal injury are discussed. These observations show that the effects of the Q-switched ruby laser are melanin-specific and melanin-dependent, and may be useful in the selective destruction of pigmented as well as superficial cutaneous lesions.

Animals↗
PubMed1996

Successful treatment of mucosal melanosis of the lip with normal pulsed ruby laser.

Melanosis of the lip is not rare in Orientals. Although it causes cosmetic problems, treatment of this pigmentary disorder is often neglected because a satisfactory tool for complete removal of mucosal melanosis has not yet been developed. The pulsed ruby laser, which has a wavelength of 694 nm and a short pulse duration of 1-2 msec, selectively damages pigmented cells in the skin. In this study, six Japanese patients with labial melanosis, manifested as labial lentigo and Peutz-Jeghers syndrome, were successfully treated with the pulsed ruby laser. The therapy achieved rapid results without producing changes in mucosal texture or recurrence after operation.

Adolescent↗
PubMed1993

Clinical use of the Q-switched ruby and the Q-switched Nd:YAG (1064 nm and 532 nm) lasers for treatment of tattoos.

BACKGROUND: The desire to remove tattoos has probably been around as long as their existence. Recent technological advances in lasers have finally made it possible to remove tattoos without leaving an equally undesirable scar. OBJECTIVE: The purpose of this article is to review the use of the Q-switched ruby (694 nm) and the Q-switched Nd:YAG (532 and 1064 nm) lasers for effective removal of tattoo ink, with cosmetically appealing results. RESULTS: The Q-switched ruby laser (694 nm) effectively removes blue-black and green ink, may treat other colors less efficiently, and is frequently associated with transient pigmentary changes, including rare depigmentation. The Q-switched Nd:YAG laser at 1064 nm quickly removes black ink, as well as other colors less efficiently; pigmentary changes are much less frequent, correlating with its lower absorption by melanin. The 532-nm wavelength treats red ink effectively, but also leads to temporary hypopigmentation. Transient textural changes may be noted at all three wavelengths discussed, but scarring is rare. CONCLUSIONS: Q-switched lasers can remove tattoos without residual scarring. Efficacy of ink removal is dependent on the wavelength used for the targeted pigment.

Adult↗
PubMed1994

Q-switched ruby laser. Further observations on treatment of professional tattoos.

The Q-switched ruby laser is effective in the treatment of amateur tattoos and other pigmented lesions. Previous studies have shown that, though amateur tattoos usually respond well, professional tattoos show greater resistance to clearing. Our study evaluates the treatment of 20 patients with 28 professional (blue, green, black) tattoos by a Q-switched ruby laser with a 28-ns pulse width, and using high energy fluences up to 10 J/cm2. Responses proved to be good to excellent among these patients, who needed fewer treatments than previously reported.

Adolescent↗
PubMed1994

Q-switched ruby laser treatment of labial lentigines in Peutz-Jeghers syndrome.

BACKGROUND. The Q-switched ruby laser emits energy with a 694-nm wavelength and has a pulse duration in the nanosecond range, which allows selective treatment of benign pigmented lesions. Labial and perioral pigmented macules associated with Peutz-Jeghers syndrome are often numerous and cosmetically disfiguring. RESULTS/CONCLUSION. We report successful treatment of these lentigines with the Q-switched ruby laser and consider it the treatment of choice for these lesions.

Adult↗
PubMedDate not supplied

Q-switched ruby laser treatment of traumatic tattooing induced by pencil point puncture in children.

Traumatic tattoos induced by pencil point puncture in children may result in persistent disfigurement if left untreated. The Q-switched ruby laser effectively removes darkly colored cutaneous chromophores with minimal disruption of unaffected skin. We present a young patient with pencil point induced traumatic tattooing of the face, suffered 1 year prior to presentation, who was successfully treated with the Q-switched ruby laser with excellent cosmetic results.

Child↗
PubMed1965

Retina: pathology of neodymium and ruby laser burns.

Chorioretinal lesions hiave been prodluced in monkeys during experitments with ruby and neodlymium lasers. Most of the energy from the ruby laser (wavelength 6943 angstroms) is absorbed by the pigment epithelium, where the greatest damage appears. With the neodymium laser (10,600 angstroms) the neural portions of the retina absorb more of damage than the pigment epithelium and adjacent tissues.

Animals↗
PubMed1996

Polymorphs of Alumina Predicted by First Principles: Putting Pressure on the Ruby Pressure Scale

Fully optimized quantum mechanical calculations indicate that Al2O3 transforms from the corundum structure to the as yet unobserved Rh2O3 (II) structure at about 78 gigapascals, and it further transforms to Pbnm-perovskite structure at 223 gigapascals. The predicted x-ray spectrum of the Rh2O3 (II) structure is similar to that of the corundum structure, suggesting that the Rh2O3 (II) structure could go undetected in high-pressure x-ray measurements. It is therefore possible that the ruby (Cr3+-doped corundum) fluorescence pressure scale is sensitive to the thermal history of the ruby chips in a given experiment.

Journal Article↗
PubMed1975

Histopathology of ruby and argon laser lesions in monkey and human retina. A comparative study.

Suprathreshold fundus lesions produced by ruby and argon laser photocoagulation were studied within 24 hours by light and electron microscopy. It was shown that damage was maximal in the outer retina in all ruby laser lesions and extramacular argon laser lesions. In both monkey and human, inner retinal damage occurred independently of outer retinal damage in macular lesions produced by the argon laser. In lesions produced by equal energy, inner retinal damage was more severe in humans than in monkeys. In both species outer retinal damage was less severe in the foveal than the parafoveal region and this disparity was greater in humans than in monkeys. These findings are important to the therapeutic use of argon laser energy for mascular disease. In particular, absortion of energy in the inner retina reduces the energy available in the treatment of subretinal lesions in the foveal area, and causes unwanted neuroretinal damage. The higher sensitivity to argon laser irradiation of the human fovea compared with the monkey fovea, has not been appreciated when defining laser safety limits.

Animals↗
PubMed1992

Q-switched ruby laser therapy of nevus of Ota.

BACKGROUND: The Q-switched ruby laser has been demonstrated to provide selective photothermolysis of pigmented tissue at a wavelength of 694 nm and a pulse width of 40 ns with dermal penetration. It was used to treat 15 patients with nevus of Ota involving the face with an age range of 6 to 52 years. Other methods of treatment for the nevus of Ota have either left scarring or were ineffective. The clinical efficacy of this laser treatment was evaluated in a comparative photographic analysis. OBSERVATIONS: Complete clearing was noted in four of the 15 patients and a minimum of 50% lightening of the original color in the remaining 11. Ten of the 15 patients were Asian, two were white, two were Hispanic, and one was Indian. The energy fluence used varied between 6 and 10 J/cm2, and the number of treatments ranged from 1 to 7. Significant lightening or clearing was found at the higher energy ranges of 9 to 10 J/cm2 with significantly less lightening noted at the lower energy range of 6 to 8.5 J/cm2. No scarring was noted in any of the 15 patients, and some isolated hypopigmentation was noted in one of the subjects. Transient postinflammatory hyperpigmentation of 2 months' duration was noted in only one patient. CONCLUSION: Q-switched ruby selective photothermolysis appears to be an effective and safe method of lightening or removing nevus of Ota.

Adolescent↗
PubMed1991

Q-switched ruby laser irradiation of normal human skin. Histologic and ultrastructural findings.

The Q-switched ruby laser is used for treatment of tatoos. The effects of Q-switched ruby laser pulses on sun-exposed and sun-protected human skin, as well as senile lentigines, were investigated with clinical observation, light microscopy, and transmission electron microscopy. A pinpricklike sensation occurred at radiant exposures as low as 0.2 J/cm2. Immediate erythema, delayed edema, and immediate whitening occurred with increasing radiant exposure. The threshold for immediate whitening varied inversely with skin pigmentation, ranging from a mean of 1.4 J/cm2 in lentigines to 3.1 J/cm2 in sun-protected skin. Transmission electron microscopy showed immediate alteration of mature melanosomes and nuclei within keratinocytes and melanocytes, but stage I and II melanosomes were unaffected. Histologically, immediate injury was confined to the epidermis. There was minimal inflammatory response 1 day after exposure. After 1 week, subthreshold exposures induced hyperpigmentation, with epidermal hyperplasia and increased melanin staining noted histologically. At higher radiant exposures, hypopigmentation occurred with desquamation of a pigmented scale/crust. All sites returned to normal skin color and texture without scarring within 3 to 6 months. These observations suggest that the human skin response to selective photothermolysis of pigmented cells is similar to that reported in animal models, including low radiant exposure stimulation of melanogenesis and high radiant exposure lethal injury to pigmented epidermal cells.

Adult↗
PubMed1990

Treatment of tattoos by Q-switched ruby laser. A dose-response study.

Tattoo treatment with Q-switched ruby laser pulses (694 nm, 40 to 80 nanoseconds) was studied by clinical assessment and light and electron microscopy. Fifty-seven blue-black tattoos or portions thereof (35 amateur and 22 professional) were irradiated with 1.5 to 8.0 J/cm2 at a mean interval of 3 weeks. Substantial lightening or total clearing occurred in 18 (78%) of 23 amateur tattoos and 3 (23%) of 13 professional tattoos in which the protocol was completed. Response was related to exposure dose. Scarring occurred in one case, and persistent confettilike hypopigmentation was frequent. Optimal fluence was 4 to 8 J/cm2. Clinicohistologic correlation was poor. Q-switched ruby laser pulses can provide an effective treatment for tattoos.

Adult↗
PubMed1965

The inheritance of yellow-larva and ruby-eye in Culex pipiens.

It has been suggested that mosquito vectors of filariasis and other diseases might be controlled by genetic methods. This is not yet possible because of the lack of genetic information concerning the vector species. The present study describes the development of a marker strain which is being used to study genetic control.Two spontaneous mutants of Culex pipiens are described, one for the first time. Ruby-eye (ru) is an autosomal recessive in linkage group 2. It is completely penetrant and completely expressed. It is evident in later instar larvae, pupae, and adults. Yellow-larva (y) is an autosomal recessive, sometimes behaving as a partial dominant, and is also in linkage group 2. It is evident in late fourth-instar larvae and pupae and is generally associated with lengthened larval development. Ruby-eye and yellow-larva are occasionally seen in collections from the field. The frequency of crossing over between ru and y differs significantly among progenies and also between the sexes, the median values being 17% in males and 24% in females.

Culex↗