Biomedical subjects

J M de Queiroz

Publications and source records attributed to J M de Queiroz.

5 recordsLinked to original sources

PubMed1993

Indocyanine green-enhanced diode laser treatment of melanoma in a rabbit model.

Indocyanine green (ICG)-enhanced laser therapy was evaluated for the treatment of experimental intraocular melanoma. Immediately after an intravenous injection of ICG, a 790-nm chromophore, 810-nm semiconductor diode laser was used to irradiate Greene hamster melanomas that had been implanted in the iris of rabbits. ICG-enhanced laser treatment of melanoma (14 eyes) was compared with treatment by laser alone (4 eyes), ICG alone (1 eye), and no treatment (2 eyes). Tumors treated with ICG-enhanced laser showed no growth after treatment, as judged by clinical examination and photography. Histologically, 4 of the 14 tumors treated with ICG-enhanced laser showed total necrosis, whereas the remaining 10 tumors treated similarly demonstrated only rare viable cells around blood vessels or at the tumor periphery. Laser treatment without ICG enhancement resulted in only superficial tumor necrosis, and all four of these tumors continued to grow after treatment. With further evaluation, indocyanine green in combination with a commercially available diode laser may be useful in the treatment of ocular melanoma.

Animals↗

PubMed1993

Foucault: the imaginary sex.

Foucault has haphazardly written many things about contemporary homosexuality (we have only two short interesting interviews on the subject). But La Volonté de Savoir develops a new idea about the modern sexuality inclination; Surveiller et Punir is a real political economy of the human body; and Foucault's last two books on antiquity give us a new point of view as regards the relations of subject to desire. This combined analysis constitutes a coherent structure of proposals that helps to enlighten crucial matters relevant to the gay community, particularly when it deals with what sexual "freedom and sexual identity mean. The answers outlined by Foucault yield two questions and two meanings as regards homosexuality nowadays, which cannot be kept apart from experience, and without any need of theoretical dissociation, if we are to understand the problem better.

Cross-Cultural Comparison↗

PubMed1992

Photodynamic therapy of experimental subchoroidal melanoma using chloroaluminum sulfonated phthalocyanine.

Although photodynamic therapy has shown great promise for the treatment of a variety of malignant neoplasms, the role of this new therapeutic modality in the clinical management of intraocular tumors remains incompletely understood. This study examines the effects of photodynamic therapy using chloroaluminum sulfonated phthalocyanine on Greene hamster melanoma transplanted into the subchoroidal space in rabbits. Twenty-four hours after intravenous administration of chloroaluminum sulfonated phthalocyanine (5 mg/kg), tumors were irradiated with 675 nm of light at total light doses of 7 to 60 J/cm2. The results show that tumor growth was arrested at total light doses of 22 to 60 J/cm2. At total light doses of 15 to 21 J/cm2, tumor growth was initially arrested. However, regrowth of these tumors was apparent within 7 days. Total light doses of less than 15 J/cm2 showed no response. Complications of photodynamic therapy, such as intraretinal or subretinal hemorrhages and retinal detachment, were seen only in animals who received total light doses in excess of 43 J/cm2.

Aluminum↗

PubMed1992

Corneal toxicity study of two perfluorocarbon liquids in rabbit eyes.

Perfluorocarbon liquids are fully fluorinated, synthetic, transparent compounds with a high specific gravity. These compounds are being increasingly used as an intraoperative tool for repair of complicated retinal detachments. A potential complication of their use, however, is liquid entering the anterior chamber in aphakic patients. In the study described herein we evaluated the effects of two of these liquids when placed in the anterior chamber of the rabbit eye. Sixteen rabbit eyes underwent anterior chamber injection of 0.05 ml of either perfluoroctane, perfluoropolyether, or balanced salt solution (control eyes). Animals were monitored clinically by biomicroscopy and external photography for up to 14 days, after which they were sacrificed and the corneas processed for light and for scanning electron microscopy. The animals injected with perfluoropolyether showed more intense stromal inflammation and corneal vascularization (p less than 0.02) than did those that received perfluoroctane. However, the perfluoroctane group showed more of the "fish-egging" phenomenon (p less than 0.03). Loss of endothelial cells was similar in the two groups, as determined by light and scanning electron microscopy. These results suggest that the corneal toxicity of these two perfluorocarbon liquids is such that their use as vitreous substitutes should be limited to short-term replacement.

Animals↗

PubMed1992

Subretinal perfluorocarbon liquids. An experimental study.

Perfluorocarbon liquids (PFCL) are fully fluorinated, synthetic, transparent compounds with a high specific gravity. These compounds are being increasingly used as an intraoperative tool for repair of complicated retinal detachments. A known complication of their use, however, is liquid entering the subretinal space via a retinal break. The purpose of this study was to evaluate the effects of two of these liquids when placed subretinally in the rabbit eye. Vitrectomy, retinotomy, and subretinal injection of 0.03 cc of either perfluoroctane, perfluorotributylamine, or balanced salt solution (control eyes) were performed on 36 rabbit eyes. Animals were monitored clinically by indirect ophthalmoscopy and fundus photography for up to 21 days. After the 21-day observation period, electroretinograms (ERG) were taken before the rabbits were killed. Histopathologic studies were done at 3 hours, 24 hours, 3 days, 7 days, 14 days, and 21 days after injection. Three eyes demonstrated tearing of the retinotomy site due to downward migration of the PFCL droplet. Results of the ERGs were normal in all animals tested. Phagocytosis of PFCL droplets by the retinal pigment epithelium (RPE) was observed in 1 eye 3 hours after injection. Three of the eyes that received PFCL injections and all of the control eyes demonstrated moderate intracellular edema of both inner and outer nuclear layers as early as 24 hours after injection. In one eye injected with PFCL, these changes progressed to swelling and cystic formation of the inner nuclear layer and mild degeneration of the outer photoreceptor segments 3 days after injection. It was assumed that these effects occurred on a mechanical basis and were not related to PFCL toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗