In oculo transplants of myometrium from postpartum guinea pigs fail to support sympathetic reinnervation. (1/841)

Sympathetic nerves to the enlarged fetus-containing region of the uterus undergo degenerative changes during late pregnancy and show slow regrowth after parturition. It is not known whether this unusual response of sympathetic nerves to smooth muscle hypertrophy is due to the sensitivity of short adrenergic neurons to hormonal changes, or whether the nerves respond to changes in the neurotrophic capacity of the target. We have investigated this question using in oculo transplantation. Small pieces of myometrium from the uterine horn of virgin guinea pigs, or from the region previously occupied by the placenta and fetus in postpartum guinea pigs, were transplanted into the anterior eye chamber. After 3 wk in oculo, the pattern of reinnervation of the transplants was assessed on whole mount stretch preparations stained for tyrosine hydroxylase. The histology of the transplants was examined in toluidine blue-stained semithin sections. Myometrial transplants from virgin donors and uterine artery transplants from both virgin and postpartum donors became organotypically reinnervated by sympathetic fibres from the host iris. In contrast, sympathetic nerves did not reinnervate myometrial transplants from postpartum donors, although they approached the transplants and became distributed in the surrounding connective tissue. All transplanted tissues showed a normal histological appearance. Both the myometrium and uterine artery from postpartum donors retained a hypertrophic appearance after 3 wk in oculo. We interpret these results to indicate that the degeneration of sympathetic nerves in late pregnancy, as well as their slow regrowth to the uterus after delivery, may be due to changes in uterine smooth muscle rather than a particular sensitivity of short adrenergic neurons to hormonal changes.  (+info)

Latrunculin-A causes mydriasis and cycloplegia in the cynomolgus monkey. (2/841)

PURPOSE: To determine the effect of latrunculin (LAT)-A, which binds to G-actin and disassembles actin filaments, on the pupil, accommodation, and isolated ciliary muscle (CM) contraction in monkeys. METHODS: Pupil diameter (vernier calipers) and refraction (coincidence refractometry) were measured every 15 minutes from 0.75 to 3.5 hours after topical LAT-A 42 microg (approximately 10 microM in the anterior chamber [AC]). Refraction was measured every 5 minutes from 0.5 to 1.5 hours after intracameral injection of 10 microl of 50 microM LAT-A (approximately 5 microM in AC), with intramuscular infusion of 1.5 mg/kg pilocarpine HCl (PILO) during the first 15 minutes of measurements. Pupil diameter was measured at 1 and 2 hours, and refraction was measured every 5 minutes from 1 to 2 hours, after intravitreal injection of 20 microl of 1.25 mM LAT-A (approximately 10 microM in vitreous), with intramuscular infusion of 1.5 mg/kg PILO during the first 15 minutes of measurements (all after topical 2.5% phenylephrine), and contractile response of isolated CM strips, obtained <1 hour postmortem and mounted in a perfusion apparatus, to 10 microM PILO +/- LAT-A was measured at various concentrations. RESULTS: Topical LAT-A of 42 microg dilated the pupil without affecting refraction. Intracameral LAT-A of 5 microM inhibited miotic and accommodative responses to intramuscular PILO. Intravitreal LAT-A of 10 microM had no effect on accommodative or miotic responses to intramuscular PILO. LAT-A dose-dependently relaxed the PILO-contracted CM by up to 50% at 3 microM in both the longitudinal and circular vectors. CONCLUSIONS: In monkeys, LAT-A causes mydriasis and cycloplegia, perhaps related to its known ability to disrupt the actin microfilament network and consequently to affect cell contractility and adhesion. Effects of LAT-A on the iris and CM may have significant physiological and clinical implications.  (+info)

Effect of pilocarpine on visual acuity and on the dimensions of the cornea and anterior chamber. (3/841)

The effect of pilocarpine on visual acuity and on the dimensions of the cornea, anterior chamber, and lens were studied in two groups of subjects. Significant changes in ocular tension, corneal curvature, anterior chamber depth, and lens anterior radius were found in a group of 55 glaucomatous eyes as a result of pilocarpine treatment, but there was no change in corneal thickness. Out of 102 glaucomatous eyes 78 became relatively myopic, and this appears to be due to changes in the dimensions of the lens of the eye similar to those occurring in accommodation, as a result of the effect of the drug on the ciliary muscle. The effect of pilocarpine on anterior chamber depth, area, and volume was studied in 125 eyes using a photographic method, and a significant reduction in the dimensions of the anterior chamber was observed as a result of the administration of pilocarpine. A significant correlation between depth and volume was also noted and the implications of this are discussed.  (+info)

Lens extraction with ultrasound. Experiments in rabbits. (4/841)

The extraction of the rabbit lens is described using a 25 G irrigating needle and a 22 G aspirating needle; at the latter's bevelled tip lens fragmentation occurs due to the longitudinal ultrasonic vibrations generated there--an 'acoustic horn' causes the tip to vibrate with large amplitudes. The use of small needles allows considerable manoeuvrability in the anterior chamber and usually eliminates the need for corneal suturing. Push-pull coupled syringes equate the volume of irrigation with that of aspiration. This procedure makes possible lens extraction through an aperture in the anterior capsule of the rabbit's lens and a similar machine is being constructed for trial on human cataract.  (+info)

Latrunculin-A increases outflow facility in the monkey. (5/841)

PURPOSE: To determine the effect of Latrunculin (LAT)-A, a macrolide that binds to G-actin, which leads to the disassembly of actin filaments, on shape, junctions, and the cytoskeleton of cultured bovine aortic endothelial cells (BAECs) and on outflow facility in living monkeys. METHODS: Latrunculin-A dose-time-response relationships in BAECs were determined by immunofluorescence and phase contrast light microscopy, facility by two-level constant pressure anterior chamber perfusion. RESULTS: In BAECs, LAT-A caused dose- and incubation time- dependent destruction of actin bundles, cell separation, and cell loss. Cell-cell adhesions were more sensitive than focal contacts. Recovery was also dose- and time-dependent. In monkeys, exchange intracameral infusion and topical application of LAT-A induced dose- and time-dependent several-fold facility increases. The facility increase was completely reversed within several hours after drug removal. However, for at least 24 hours after a single topical LAT-A dose, perfusion with drug-free solution caused an accelerated increase in facility beyond that attributed to normal resistance washout. CONCLUSIONS: Pharmacological disorganization of the actin cytoskeleton in the trabecular meshwork by specific actin inhibitors like LAT-A may be a useful antiglaucoma strategy.  (+info)

Effect of staurosporine on outflow facility in monkeys. (6/841)

PURPOSE: To determine the effect of the serine-threonine kinase inhibitor staurosporine on outflow facility in living monkeys. METHODS: Total outflow facility was determined by two-level constant pressure perfusion of the anterior chamber bilaterally before and after intracameral infusion of staurosporine or vehicle in opposite eyes. RESULTS: Intracameral staurosporine dose-dependently doubled outflow facility, with 0.1 microM, 1 microM, and 10 microM being subthreshold, effective, and maximal doses, respectively. At 50 microM, intracameral staurosporine was less effective than 10 microM on facility and induced corneal toxicity. CONCLUSIONS: The broad-spectrum protein kinase inhibitor staurosporine increases outflow facility in living monkeys, perhaps by affecting the trabecular meshwork cytoskeleton.  (+info)

Epithelial ingrowth of anterior chamber and anterior surface of vitreous. (7/841)

This study is a case report of the histopathologic findings of the anterior chamber epithelial ingrowth in a patient who had penetrating injury in the right eye from an arrow approximately 20 years ago. The patient underwent the enucleation in the right eye due to pthisis bulbi and was fitted with a prosthetic eye. Specimens were prepared from the enucleated right eye for histopathologic observation using hematoxyllin-eosin to be observed under light microscopy. Epithelial ingrowth in the anterior chamber was noted in one layer or multi-layered epithelial cell growth. The ingrowth had spread to the posterior surface of the cornea to the anterior chamber angle, to the iris surface, and to the anterior surface of the vitreous. The finding suggests that epithelial ingrowth could invade even through a perforation site and spread wherever the cells could reach.  (+info)

T cell immunity induced by allogeneic microglia in relation to neuronal retina transplantation. (8/841)

Microglia share a lineage relationship with bone marrow-derived monocytes/macrophages and dendritic cells, and their inclusion in retinal and brain transplants may function as "passenger leukocytes. " In other solid allografts, passenger leukocytes are the primary sources of immunogenicity, triggering alloimmune rejection. We have conducted a series of in vitro and in vivo studies examining the capacity of microglia cultured from forebrain to activate alloreactive T cells and to induce and elicit alloimmunity. Cultured microglia expressed class II MHC molecules and costimulatory molecules (B7-1, B7-2, and CD40), and they secreted IL-12. Cultured microglia injected s.c. into naive recipients induced allospecific delayed hypersensitivity and elicited delayed hypersensitivity directed at alloantigens. Cultured microglia differed from conventional APCs by secreting significant amounts of mature TGF-beta2, but smaller amounts of IL-12. Moreover, while both cultured microglia and conventional APC stimulated T cell proliferation in vitro, microglia directed the responding T cells toward the Th2 pathway in which IL-4, but not IL-2 and IFN-gamma, was secreted. The abilities of microglia to secrete TGF-beta2, to stimulate alloreactive Th2 cells, and to induce anterior chamber associated immune deviation when injected into the eye of naive allogeneic mice suggest that they are not typical passenger leukocytes. The unique functional properties of cultured microglia may account for the capacity of neonatal retinal tissue transplanted into the eye to alter the systemic alloimmune response in a manner that delays, but does not prevent, graft rejection.  (+info)