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Biomedical subjects

T J Stafford

Publications and source records attributed to T J Stafford.

At least 19 recordsLinked to original sources

Role of the Alexandrite laser for removal of tattoos.

BACKGROUND AND OBJECTIVE: The development of the Alexandrite laser for the removal of blue-black tattoos is described. STUDY DESIGN/MATERIALS AND METHODS: The responses of an animal study, using professionally tattooed skin and a human study involving 22 (professional and nonprofessional) blue-black tattoos, to the Alexandrite laser are reported. RESULTS: Histopathologic evaluation of tattooed pig skin biopsies demonstrated the method of removal of dermal tattoo pigment. An average 11.6 treatments were required to remove completely the ten human blue-black professional tattoos compared to an average of 10.3 treatments to reach the same endpoint in six subjects with nonprofessional tattoos. CONCLUSION: Of significance was the fact that unlike the Q-switched Ruby and Nd:YAG lasers where punctate bleeding and tissue splattering have been reported to occur during laser tattoo removal, epidermal integrity was maintained during exposure of tattooed skin to the Q-switched Alexandrite laser at therapeutic fluences used.

Adult↗

Removal of colored tattoos with the Q-switched alexandrite laser.

The Q-switched alexandrite laser at 760 nm and 50- to 100-ns pulse duration has been shown to effectively remove blue-black as well as green, red, and mauve in seven human subjects with colored tattoos. An average of 9.0 treatments were required to completely remove the green pigment at an average fluence of 5.80 J/cm2 compared with an average of 9.7 treatments at an average fluence of 6.10 J/cm2 for red and an average of 10 treatments at an average fluence of 6.20 J/cm2 for mauve. Orange and yellow were unaffected by the alexandrite laser over a range of fluences tested.

Animals↗

Pulsed dye laser treatment of recalcitrant verrucae: a preliminary report.

Patients with recalcitrant warts on the fingers and hands, periungual, and other parts of the body including verrucae plana and plantar surfaces were treated using the pulsed dye laser at 585 nm, 450 usec, and a spotsize of 5 mm diameter. Of the 39 patients treated, 28 (72%) were cleared of their warts after an average of 1.68 treatments at fluences of 6.25-7.5 J/cm2. Seven (18%) patients had a reduction of between 80-95% of their warts after 1.3 treatments, and verrucae reduced by 50% in four of the 39 patients after one treatment. The average follow-up period of the 28 cases cleared of their warts has been 5 months. Of this group, those with periungual warts have been followed for up to 6.4 months, compared to 4.8 months for those with warts on other parts of their body, 4.0 months for those with finger and hand warts, and 2.0 months for plantar warts. Only one of the 28 patients has had a recurrence after 3 months of clearance.

Adolescent↗

EMLA for laser treatment of portwine stains in children.

Vascular-specific lasers with pulse durations of between 300 and 500 microseconds are the treatment of choice for portwine stains (PWS), particularly in children. Although the discomfort felt following laser irradiation from a single pulse is transient, these sensations are intensified when multiple pulses are delivered over a confined area of skin. Because 75-80% of PWS are located in the head and neck regions, laser treatment of these sites tends to be more painful than those located in most other parts of the body. A prospective double blind randomized study, assessing pain during laser irradiation on PWS skin occluded with either EMLA, placebo, or no cream (control) was performed in 73 PWS subjects between 5 and 16 years of age. Analysis of the data showed that the pain scores for EMLA-treated sites were the smallest, the control scores tended to be the highest, with the placebo scores in the middle. The differences between the treatments were significant (P < 0.0001).

Adolescent↗

Location of port-wine stains and the likelihood of ophthalmic and/or central nervous system complications.

Of 310 patients with port-wine stains, 68% had more than one dermatome involved; 85% had unilateral and 15% had a bilateral distribution of their port-wine stain. At the time of examination, 8% of all patients with trigeminal port-wine stains had evidence of eye and/or central nervous system (CNS) involvement. Extensive involvement, with port-wine stain over the trunk and extremities as well as the head and neck, was observed in 12%. Patients who did not have port-wine stains on the areas served by branches V1 and V2 of the trigeminal nerve had no signs or symptoms of eye and/or CNS involvement. Port-wine stains of the eyelids, bilateral distribution of the birthmark, and unilateral port-wine stains involving all three branches of the trigeminal nerve were associated with a significantly higher likelihood of having eye and/or CNS complications. Twenty-four percent of those with bilateral trigeminal nerve port-wine stains had eye and/or CNS involvement compared with 6% of those with unilateral lesions. All those who had eye and/or CNS complications had port-wine stain involvement of the eyelids; in 91% both upper and lower eyelids were involved, whereas in 9% only the lower eyelid was involved. None of those with upper eyelid port-wine stains alone had eye and/or CNS complications. In addition, 3 (75%) of the 4 subjects with seizures alone had bilateral port-wine stain involvement. A third group, these with unilateral V1, V2, and V3 port-wine stains, had eye and/or CNS complications in 3 (19%) of 16 subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗

Histologic comparison of the pulsed dye laser and copper vapor laser effects on pig skin.

Albino pig skin was exposed to the copper vapor (CVL) and flash-lamp pulsed dye (PDL) lasers at 578 nm with a 3 mm diameter spotsize over a range of fluences until purpura and whitening were first established. The total irradiation time was the parameter that was varied in order for the CVL to reach the desired fluence. The lowest fluence producing each clinical endpoint was designated the threshold fluence: 34 J/cm2 was required to produce purpura using the CVL compared to 7.5 J/cm2 with the PDL laser. Histologically, skin exposed to purpura fluences from the CVL revealed the presence of constricted, disrupted papillary dermal blood vessels with trapped RBC's within them which were unlike those exposed to PDL where the irradiated vessels were dilated and packed with masses of intravascular agglutinated RBC's. The whitening threshold fluences for the CVL and PDL lasers were 67 J/cm2 and 29 J/cm2, respectively. Streaming of epidermal cells and dermal collagen denaturation were observed in CVL irradiated skin, compared to occasional dyskeratotic epidermal cells and focal dermal collagen denaturation following PDL exposure. The mechanisms responsible for the clinical and histologic changes produced by the two laser systems are discussed.

Animals↗

Treatment of port-wine stains at 577 nm: clinical results.

A pulsed, dye laser at 577 nm was used to treat 65 patients with port-wine stains. Results clearly indicate that the laser parameters of dose, wavelength, and pulse duration contribute to the outcome of laser treatment of port-wine stains.

Adolescent↗

Spontaneous degenerative maculopathy in the monkey.

Maculopathy has many varied facets. The subhuman diurnal primate demonstrates some of the changes occasionally seen in clinical practice. Examination of 574 diurnal subhuman primates, mostly older rhesus monkeys, revealed the following: drusen-like bodies in the macula and frequently elsewhere in the eye grounds of 5.9%; crescent shaped lesions suggestive of choroidal rupture; and macular and perimacular lesions associated with myopia and complicated by choroidal neovascular ingrowth.

Age Factors↗