[Ultrastructural evaluation of mitomycin C toxic effects on the ciliary epithelium of normal rabbits eyes with and without aqueous humor suppressant treatment]. / Avaliação ultra-estrutural dos efeitos tóxicos da mitomicina C no epitélio ciliar de olhos de coelhos normais com e sem tratamento hipotensor ocular prévio.

PURPOSE: To evaluate the effects of mitomycin C (MMC) on the internal ciliary epithelium (ICE) of the ciliary body of animals treated with two different aqueous humor suppressants. METHODS: The eyes of sixteen Norfolk albino rabbits divided into four experimental groups were studied. The right eyes (RE) of the four groups received 0.1 ml of MMC (0.5 mg/ml) under the scleral flap. The left eyes (LE) was the control group. Group 1 (G1) did not have any other treatment. To Group 2 (G2) and Group 4 (G4) acetazolamide was administered. To Group (G3) and Group 4 (G4) timolol maleate was administered. ICE was examined by transmission electron microscopy (TEM). RESULTS: The following aspects were observed in all groups, except in G1 LE: cell shrinkage and/or enlargement of intercellular spaces, rarefied mitochondria, clear vesicular structures and electron-dense bodies. The internal limitant membrane showed to be thickened, discontinued and separated in all groups, except in G1 LE and G2 LE. Discharge of cytoplasmatic material was observed only in the groups treated with aqueous humor suppressants. CONCLUSIONS: 1) MMC, acetazolamide and timolol maleate caused morphological alterations in the ciliary epithelium even when used alone. 2) The combination of MMC and acetazolamide caused more alterations than did isolated acetazolamide, but not more than MMC alone. 3) For the other combinations the alterations were similar.

Avaliação ultra-estrutural dos efeitos tóxicos da mitomicina C no epitélio ciliar de olhos de coelhos normais com e sem tratamento hipotensor ocular prévio / Ultrastructural evaluation of mitomycin C toxic effects on the ciliary epithelium of normal rabbits eyes with and without aqueous humor suppressant treatment

OBJETIVO: Avaliar o epitélio ciliar interno (ECI) do corpo ciliar após aplicação de mitomicina C (MMC) sob retalho escleral, em animais tratados com dois tipos de inibidores da produção do humor aquoso. MÉTODOS: Foram estudados ambos os olhos de 16 coelhos divididos em 4 grupos experimentais. Foi realizado retalho escleral em todos os olhos dos animais, mas apenas os olhos direitos (OD) receberam MMC. No grupo 1 (G1) não houve tratamento prévio. Nos grupos G2 e G4 foi administrada acetazolamida e nos grupos G3 e G4 maleato de timolol. O ECI foi examinado à microscopia eletrônica de transmissão (MET). Os olhos esquerdos formaram os grupos controle. RESULTADOS: Em todos os grupos exceto no G1 OE, foram observadas: retração das células e/ou alargamento entre invaginações, mitocôndrias com rarefação, vesículas claras e corpos densos. A membrana limitante interna estava espessada, descontínua ou descolada em todos grupos exceto G1 OE e G2 OE. Foi observada liberação de material citoplasmático apenas nos grupos tratados com inibidores da produção de humor aquoso. CONCLUSÕES: 1- MMC, acetazolamida e maleato de timolol causaram alterações morfológicas no epitélio ciliar mesmo usados isoladamente. 2- A associação MMC e acetazolamida causou mais alterações do que a acetazolamida isoladamente, mas não mais do que a MMC isoladamente. 3- Nas demais associações as alterações foram semelhantes.

PURPOSE: To evaluate the effects of mitomycin C (MMC) on the internal ciliary epithelium (ICE) of the ciliary body of animals treated with two differents aqueous humor supressants. METHODS: The eyes of sixteen Norfolk albino rabbits divided into four experimental groups were studied. The right eyes (RE) of the four groups received 0.1 ml of MMC (0.5 mg/ml) under the scleral flap. The left eyes (LE) was the control group. Group 1 (G1) did not have any other treatment. To Group 2 (G2) and Group 4 (G4) acetazolamide was administered. To Group (G3) and Group 4 (G4) timolol maleate was administered. ICE was examined by transmission electron microscopy (TEM). RESULTS: The following aspects were observed in all groups, except in G1 LE: cell shrinkage and/or enlargement of intercellular spaces, rarefied mitochondria, clear vesicular structures and electron-dense bodies. The internal limitant membrane showed to be thickened, discontinued and separeted in all groups, except in G1 LE and G2 LE. Discharge of cytoplasmatic material was observed only in the groups treated with aqueous humor supressants. CONCLUSIONS: 1) MMC, acetazolamide and timolol maleate caused morphological alterations in the ciliary epithelium even when used alone. 2) The combination of MMC and acetazolamide caused more alterations than did isolated acetazolamide, but not more than MMC alone. 3) For the other combinations the alterations were similar.

Influência da citoplegia sobre a açäo hipertensora do latanoprost em indivíduos normais / Influence of citoplegia on the hypotensive latanoprost effect on normal subjects

Avaliar a influência da citoplegia sobre a açäo hipotensora ocular do latanoprost em indivíduos normais. Pacientes, materiais e métodos: Foram estudados 17 volutários normais, sem antecedentes de doenças oculares crônicas, trauma ou cirurgias. Foi instilado latanoprost 0,005 por cento em ambos os olhos e após 20 minutos foi instilado ciclopentolato 1 por cento no olho direito. A pressäo intra-ocular (Po) foi medida, pela tonometria de aplanaçäo de Goldmann, antes da instilaçäo do latanoprost e após 20 minutos, 1 hora e 20 minutos, 3 horas e 20 minutos e 4 horas e 20 minutos. A Po foi comparada entre o olho direito (OD) e o olho esquerdo (OE) pelo teste de Wilcoxon. A comparaçäo entre as medidas realizadas em cada olho nas diferentes fases de estudo foi procedida pelo teste de Friedman. A variaçäo percentual da Po foi calculada em cada tempo e comparada entre OD e OE.

The effects of RGD (Arg-Gly-Asp) peptides on glaucoma filtration surgery in rabbits.

BACKGROUND AND OBJECTIVE: Integrins are the main mediators of the interaction between fibroblasts and extracellular matrix (ECM) during scar formation. The adhesion motive RGD (Arg-Gly-Asp) is contained in the ECM and is recognized by the integrin receptor. Soluble peptides containing the RGD sequence can compete with -RGD- contained in the ECM for binding to the integrin receptor and thus prevent cell adhesion and scar formation. MATERIALS AND METHODS: The peptides RGD (p602), GRGDSP (p603), GRGDSPCA (p604), and GGRGDSPCA (p605) were used in 25 glaucoma filtering surgeries in rabbits (five eyes per peptide and five with saline). RESULTS: Postoperative subconjunctival injections of peptides were given at days 0, 4, 8, 12, and 16. Bleb size, bleb survival, and signs of toxicity were examined. The GRGDSPCA and GGRGDSPCA showed an increase in bleb formation, size, and survival with no clinical signs of toxicity compared with controls (P < .008). Histopathologic evaluation confirmed inhibitory effects in scar formation with bleb formation, and transmission electron microscopy demonstrated that there was no toxicity to the ciliary body. CONCLUSION: These peptides were effective in controlling scar formation in glaucoma filtering surgery.

Biochemical studies on the secretion of glycoproteins by isolated ciliary body of rabbits.

The contribution of the ciliary body to the origin of vitreous proteins was investigated in rabbits by incubating explants of this eye component under novel conditions. At the end of incubations for up to 21 h, the tissues were processed histologically and were shown to be in an excellent state of morphological preservation. When radioactive amino acids and fucose were added to the culture medium, protein and glycoprotein synthesis and secretion were detected using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) plus fluorography. The origin of these secretory products was traced by autoradiography to the ciliary epithelium. When samples of vitreous bodies - injected intravitreally with the same radioactive precursors - were run beside samples of the tissue culture media, comigration of at least 8 radioactively labelled bands including the one previously identified as transferrin was detected. This indicates that some vitreous proteins may be secreted by the ciliary body and that cultures of explants of ciliary body-iris are useful tools for studies on vitreous protein secretion.

Açäo da mitomicina C nas estruturas intraoculares de coelhos / Action of mitomicin C in intraocular structure of rabbits

Injetamos no espaço vítreo, mitomicina C em concentraçöes de 0,1 mg/0,1 ml e 0,5 mg/0,1 ml e, deixamos a droga ser absorvida nos tecidos oculares, por difusäo, sem removê-la cirurgicamente. A mitomicina é altamente lesiva para a retina, coróide e corpo ciliar, levando à necrose isquêmica desses tecidos nas duas concentraçöes usadas (o,1 mg e 0,5 mg) sendo que as alteraçöes da retina e do cristalino foram mais graves no grupo de maior concentraçäo e nesse grupo os olhos foram para atrofia. A necrose total da retina ocorreu em todos os olhos do grupo 2 (mitomicina 0,5 mg) (100 por cento) e em 21 por cento dos olhos do grupo 1 (mitomicina 0,1mg) neste grupo houve maior incidência de necrose parcial da retina (63,9 por cento). A incidência de necrose parcial da retina (63,9 por cento). A incidência de necrose isquêmica da coróide e corpo ciliar também foram maiores no grupo 2 (mitomicina 0,5 mg), tendo ocorrido necrose total em todos os olhos neste grupo.

Drogas parassimpaticolíticas na terapêutica ocular / Parasympatholytics drugs in ocular therapeutic

Os autores fazem uma revisao dos aspectos farmacológicos de drogas anticolinérgicas na terapia ocular. É demonstrado o fármaco de escolha para algumas situaçoes práticas dentro da clínica oftalmológica e também se procede a um estudo comparativo entre essas mesmas drogas. Com isso, procura-se trazer ao clínico uma visao prática do uso desses fármacos, o que, certamente, contribuirá para esclarecer alguma situaçoes do dia-a-dia da práxis médica.

Effects of pertussis toxin on intraocular pressure and adenylate cyclase activity of ciliary processes in rabbits.

The effects of pertussis toxin on the intraocular pressure (IOP) lowering effect of clonidine and isoproterenol as well as on the inhibitory effects of clonidine and neuropeptide Y on adenylate cyclase activity of ciliary processes were studied in albino rabbits. I.v. administered pertussis toxin elicited transient changes in IOP which, however, returned to control values during 2-3 days. In the following days the IOP lowering effect of the alpha 2-adrenergic agonist clonidine was abolished and that of the nonselective beta-adrenergic agonist isoproterenol was attenuated. At the same time, the inhibitory effects of clonidine and neuropeptide Y on basal as well as stimulated adenylate cyclase activities in homogenates of ciliary processes were grossly diminished. The effects of pertussis toxin on the IOP lowering action of adrenergic agonists and on the inhibitory action of clonidine and neuropeptide Y on adenylate cyclase activity were ascribed to an impairment of the function of a G protein in ciliary processes, probably G(i) protein. It is suggested that the decrease of IOP induced by clonidine is due to inhibition of adenylate cyclase.

Vascular effects of acetylcholinesterase inhibitors in the rabbit eye: a study with fasciculin and physostigmine.

The vascular effects of fasciculin and physostigmine, two acetylcholinesterase inhibitors, were studied with radioactively labelled microspheres in the rabbit eye. In addition, the effects on the intraocular pressure, pupil size and the aqueous humor protein concentration were determined. Both drugs were injected intracamerally in pentobarbital anesthetized and indomethacin pretreated animals. Fasciculin injected in a dose of 0.5 micrograms (0.7 x 10(-10)M) reduced blood flow in the anterior uvea as determined 30 and 60 min after injection. Higher doses had inconsistent effects. Physostigmine injected in a dose of 3 micrograms (1.1 x 10(-8)M) also reduced blood flow in the anterior uvea. The effect was most pronounced in the iris. Neither drug had any appreciable effect on choroidal or retinal blood flow. Both drugs caused pupillary constriction but the reduction in blood flow was not secondary to miosis. The effects on the intraocular pressure and aqueous humor protein concentration were inconsistent. The reduction in blood flow of the anterior uvea after intracameral injection of acetylcholinesterase inhibitors is consistent with a cholinergic vasoconstriction previously described in the eye during electrical stimulation of the oculomotor nerve.