Layer specific regulation of critical period timing and maturation of mouse visual cortex by endocannabinoids.

Plasticity during the critical period is important for the functional maturation of cortical neurons. While characteristics of plasticity are diverse among cortical layers, it is unknown whether critical period timing is controlled by a common or unique molecular mechanism among them. We here clarified layer-specific regulation of the critical period timing of ocular dominance plasticity in the primary visual cortex. Mice lacking the endocannabinoid synthesis enzyme diacylglycerol lipase-α exhibited precocious critical period timing, earlier maturation of inhibitory synaptic function in layers 2/3 and 4, and impaired development of the binocular matching of orientation selectivity exclusively in layer 2/3. Activation of cannabinoid receptor restored ocular dominance plasticity at the normal critical period in layer 2/3. Suppression of GABAA receptor rescued precocious ocular dominance plasticity in layer 4. Therefore, endocannabinoids regulate critical period timing and maturation of visual function partly through the development of inhibitory synaptic functions in a layer-dependent manner.

Dark Rearing Promotes the Recovery of Visual Cortical Responses but Not the Morphology of Geniculocortical Axons in Amblyopic Cat.

Monocular deprivation (MD) of vision during early postnatal life induces amblyopia, and most neurons in the primary visual cortex lose their responses to the closed eye. Anatomically, the somata of neurons in the closed-eye recipient layer of the lateral geniculate nucleus (LGN) shrink and their axons projecting to the visual cortex retract. Although it has been difficult to restore visual acuity after maturation, recent studies in rodents and cats showed that a period of exposure to complete darkness could promote recovery from amblyopia induced by prior MD. However, in cats, which have an organization of central visual pathways similar to humans, the effect of dark rearing only improves monocular vision and does not restore binocular depth perception. To determine whether dark rearing can completely restore the visual pathway, we examined its effect on the three major concomitants of MD in individual visual neurons, eye preference of visual cortical neurons and soma size and axon morphology of LGN neurons. Dark rearing improved the recovery of visual cortical responses to the closed eye compared with the recovery under binocular conditions. However, geniculocortical axons serving the closed eye remained retracted after dark rearing, whereas reopening the closed eye restored the soma size of LGN neurons. These results indicate that dark rearing incompletely restores the visual pathway, and thus exerts a limited restorative effect on visual function.

Safety of intracameral injection of moxifloxacin using total replacement technique (bag and chamber flushing).

PURPOSE: To assess the safety of intracameral injection of moxifloxacin (MFLX) using the total replacement technique [bag and chamber (BC) flushing]. METHODS: The anterior chamber including the area behind the intraocular lens was irrigated and replaced using BC flushing. In Group A, 36 patients received balanced salt solution irrigation in the right eye and intracameral MFLX (150 µg/mL: 33-fold dilution of 0.5% eye drops) in the left eye. In Group B, 33 patients received intracameral MFLX in the right (500 µg/mL: 10-fold dilution) and left eyes (150 µg/mL: 33-fold dilution). Visual acuity, intraocular pressure, corneal endothelial cell density, corneal thickness, and foveal thickness were recorded before and up to 3 months after surgery. RESULTS: In either group, there were no statistically significant differences between the right and left eyes with respect to visual acuity, intraocular pressure, corneal endothelial cell count, and foveal thickness before and at 3 months after surgery. There was no difference in corneal thickness before and at 3 months after surgery. In patients who received 500 µg/mL MFLX during surgery, central corneal thickness at 1 week after surgery was significantly reduced. CONCLUSIONS: In the present study, there was no adverse effect associated with intracameral injection of 150-500 µg/mL MFLX. Moreover, our results supported the safety of BC flushing. Thus, BC flushing, which can irrigate the inside of the capsular bag and attain stable antibiotic concentrations, appears to be a favorable technique for intracameral injection of MFLX.

Assessment of vitreous drug concentration in the porcine eye following intracameral injection or irrigation with moxifloxacin.

INTRODUCTION: Posterior capsule rupture causes instant vitreous contamination, resulting in endophthalmitis. However, transfer of intracameral moxifloxacin (MFLX) to the vitreous has not been examined in detail. We investigated vitreous antibiotic concentrations following intracameral MFLX in both ruptured and intact posterior capsular eyes. METHODS: Experiment 1: Intraocular lenses were inserted into 21 extracted porcine eyes by one of the following three methods: (1) Irrigation: Throughout surgery, 33-fold diluted MFLX irrigation solution (150 µg/mL) was used; (2) Bag and chamber flushing: After surgery, the anterior chamber and area behind the intraocular lenses were irrigated with 30-fold diluted MFLX (167 µg/mL) using a 5 mL syringe; (3) Simple injection: Tenfold diluted MFLX (50 µg in 0.1 mL) was injected intracamerally at the conclusion of surgery. The eyeballs were frozen and the anterior, central, and posterior portions of the vitreous were cubed. After defrosting, concentrations were measured using high-performance liquid chromatography. Experiment 2: The same procedure was conducted for 18 eyes in which the posterior capsule had been ruptured. RESULTS: Experiment 1: Transfer of intracameral MFLX to the anterior vitreous was approximately 1% (1.56-2.20 µg/mL) regardless of the administration method. Experiment 2: MFLX reached a high concentration in the vitreous with irrigation solution administration (maximum 30.22 µg/mL). The concentrations reached by simple injection or flushing were significantly less than those obtained by irrigation. CONCLUSION: With an intact posterior capsule, intracameral MFLX exhibited limited effects on vitreous concentration. Despite the fact that the risk of infection clearly increases in cases of ruptured capsule, no special infection prevention protocol has been proposed. It was confirmed that irrigation solution caused vitreous contamination in ruptured eyes within only a short irrigation time. In this case, intracameral administration did not necessarily achieve preventive concentrations for endophthalmitis, but it appears that an effective drug concentration can be achieved in the vitreous by the administration of irrigation solution.

Regiocontrolled addition of arylboronic acids to allenes using palladium and platinum catalysts.

Studies about the regiocontrolled addition of arylboronic acids to allenes using a palladium or a platinum catalyst have been described. The selectivity of the reaction can be altered by the choice of the metal reagent and base. Contrary to the formation of endo-olefinic products in the reactions using hydroxopalladium complex, predominant production of exo-olefinic products was observed by the reaction with hydroxoplatinum complex.

Palladium-catalysed coupling reaction of allenic alcohols with aryl- and alkenylboronic acids.

The direct coupling of aryl- and alkenylboronic acids with allenic alcohols has been achieved using a palladium catalyst to yield various substituted dienes and trienes in high yields.