Dietary supplementation with green tea extract improves the antioxidant status and oocyte developmental competence in Italian Mediterranean buffaloes.

The aim of this work was to assess the antioxidant status and the developmental competence of oocytes recovered by ovum pick-up (OPU) in Italian Mediterranean buffaloes supplemented with green tea extracts (GTE) for 90 days. Buffalo cows (n = 16) were randomly assigned to a control group receiving no supplement and a treatment group, receiving GTE starting 90 days before OPU, carried out for five consecutive sessions. Blood samples were collected before the start of supplementation with GTE (T0) and at day 45 (T1) and day 90 (T2) of supplementation, to measure ferric reducing activity (FRAP), total antioxidant capacity (TAC), superoxide dismutase (SOD) and catalase (CAT). The antioxidant status of follicles was measured as TAC on the follicular fluid collected from the dominant follicle just prior OPU, coinciding with T2, and at the end of five repeated OPU sessions (T3). Another objective was to assess in vitro the protective effects of green tea extracts on hepatic cells exposed to methanol insult. Different concentrations of GTE (0.5 µM and 1 µM) were tested on cultured hepatic cells and viability, morphology and SOD activity were assessed at 24, 48 and 72 h. Supplementation with GTE increased (P < 0.05) the number of total follicles (8.7 ± 0.5 vs 6.9 ± 0.5), the number and the percentage of Grade A + B cumulus-oocyte complexes (COCs) compared with the control (3.7 ± 0.4 vs 2.3 ± 0.3 and 57.5 ± 4.2 vs 40.4 ± 4.9 %, respectively). Oocyte developmental competence was improved in the GTE group as indicated by the higher (P < 0.05) percentages of Grade 1,2 blastocysts (44.8 vs 29.1 %). In the GTE group, plasma TAC was higher both at T1 and T2, while FRAP increased only at T2, with no differences in SOD and CAT. The TAC of follicular fluid was higher (P < 0.05) in the GTE compared to the control both at T2 and at T3 The in vitro experiment showed that co-treatment with methanol and 1 µM GTE increased (p < 0.01) cell viability at 24 h (P < 0.01), 48 h (P < 0.05) and 72 h (P < 0.01) compared with the methanol treatment co-treatment with 1 µM GTE prevented the decrease in SOD activity observed with methanol at 24 and 48 h of culture. In conclusion, the results of in vivo and in vitro experiments suggest that supplementation with GTE increases buffalo oocyte developmental competence, by improving oxidative status and liver function.

Indocyanine green angiography of well-defined plaque choroidal neovascularization in age-related macular degeneration.

OBJECTIVE: To determine the natural course of well-defined plaque choroidal neovascularization (CNV) using indocyanine green angiography. METHODS: Two ophthalmologists, experts in macular diseases and indocyanine green angiography, examined 40 eyes with exudative age-related macular degeneration and a well-defined plaque CNV using complete ophthalmoscopic evaluation, fluorescein angiography, and indocyanine green angiography. The increase in the size of the plaques was analyzed using multivariate analysis, in relation to the worsening of visual acuity, with adjustment for age, sex, and length of follow-up. RESULTS: Mean follow-up was 13.5 months (median, 11 months). Initial and final mean visual acuity were 20/46 (median, 20/50) and 20/65 (median, 20/100), respectively. The mean initial size of the plaque was 6.62 mm2 (median, 6.20 mm2), and the mean final size was 10.40 mm2 (median, 9.76 mm2). The enlargement was statistically significant (P<.001). CONCLUSIONS: We found that plaque CNV tends to become larger with time, the enlargement reaching about 40% in 1 year of follow-up. The resulting loss of visual acuity, however, is not significant, and is slightly correlated with the extension of the lesion; it also does not appear to be directly related to sex.

ICGA-guided laser photocoagulation of occult choroidal neovascularization in age-related macular degeneration. Indocyanine green angiography.

PURPOSE: To evaluate the efficacy of indocyanine green angiography (ICGA)-guided laser photocoagulation in eyes with fluorescein angiographic evidence of occult choroidal neovascularization (O-CNV) in patients with age-related macular degeneration (ARMD) with or without pigment epithelium detachment (PED). METHODS: Eighty eyes of 79 consecutive patients with O-CNV underwent laser treatment of a clearly outlined extrafoveal ICGA hyperfluorescent area, presumed to be focal CNV. Four types of presumed CNV were treated: Group 1 (20 eyes), CNV beneath the PED; Group 2 (23 eyes), CNV at the margin of the PED; Group 3 (10 eyes), parapapillary CNV and PED; and Group 4 (27 eyes), macular CNV without PED. Median follow-up was 17.5 months (range, 6-24 months). RESULTS: After 1 year, 15% of the eyes in Group 1, 30% in Group 2, 100% in Group 3, and 52% in Group 4 had obliteration of the presumed CNV. After 1 year, visual acuity was stable or improved in 18% of Group 1, in 37.5% of Group 2, in 100% of Group 3, and in 73% of Group 4. The remaining eyes worsened. CONCLUSIONS: Indocyanine green angiography-guided laser treatment may improve or stabilize visual acuity in some eyes with O-CNV. The best outcome is seen in eyes with presumed parapapillary CNV, probably made up of choroidal telangiectases in many cases. The type and location of the presumed CNV influence prognosis after laser treatment considerably. A randomized, controlled clinical study appears necessary to investigate the efficacy of ICGA-guided laser treatment in different types of presumed CNV. The inclusion criteria for further trials need to be defined with precision, as data from patients with different choroidal vascular abnormalities have been pooled until now.

Trans-ACPD reduces multiple components of synaptic transmission in the rat hippocampus.

Activation of metabotropic quisqualate receptors by trans-ACPD (trans-1-aminocyclopentane-1,3-dicarboxylic acid) caused a reduction in the amplitude of the synaptic response elicited by stimulation of the Schaffer collateral projection and recorded intracellularly from area CA1 in slices of rat hippocampus. Pharmacological agents were used to isolate components of the response mediated by N-methyl-D-aspartate (NMDA) receptors, non-NMDA receptors, and gamma-aminobutyric acid (GABA) receptors. Each of these components was reduced during the trans-ACPD application. These results indicate that one subtype of glutamate receptor may be able to decrease the synaptic efficacy of other subtypes and may provide an important means for balancing the synaptic enhancement processes often studied in the hippocampus.

Activity-induced decrease in early and late inhibitory synaptic conductances in hippocampus.

The use dependence of inhibitory postsynaptic potentials (IPSPs) and their underlying conductances was studied in area CA1 of the hippocampal brain slice preparation, using a two-pulse paradigm in which paired activation of two separate synaptic inputs resulted in changes in the second, or "primed" response. In intracellular current-clamp recordings, the "primed" response, normally triphasic, exhibited a larger, wider excitatory PSP (EPSP) component and greatly reduced or absent IPSP components. Maximal widening occurred when the interval between synaptic stimuli was between 200 and 250 msec. Hyperpolarization of the postsynaptic cell reversed both the early IPSP and the direction of change of the width of the "primed" EPSP response, suggesting that the changes in the "primed" waveform were not due to the addition of an unidentified inward current(s). Furthermore, the reduction of the IPSPs during the "primed" response could not be accounted for by the fact that the membrane potential of the postsynaptic cell was hyperpolarized and therefore closer to IPSP reversal potential. Using single-electrode voltage-clamp techniques, we found that the early inhibitory conductance generally decreased by approximately 50%, with little if any change in reversal potential. The late inhibitory conductance also showed a priming-induced decrease of approximately 95%. Finally, "primed" four-pulse bursts of stimuli induced a larger depolarization in the postsynaptic cell than did unprimed bursts, also with an optimal interval of about 250 msec. We conclude that activation of certain synaptic pathways in the hippocampus results in a temporal window of 200-300 msec during which inhibitory synaptic activity is depressed and excitatory synaptic transmission is maximally effective, especially if the excitation occurs in short bursts. Such a mechanism would endow the inhibitory synaptic components of the hippocampus with a "gating" function to control long-term synaptic modification at excitatory synapses in the same region.

Activity-induced depression of synaptic inhibition during LTP-inducing patterned stimulation.

In the hippocampus, patterns of electrical stimulation that approximate bursting neuronal activity during theta rhythm have been shown to induce a long-term potentiation (LTP) of excitatory synapses. In this study, a single subthreshold stimulus applied to one set of Schaffer/commissural fibers affected the response to a second stimulation delivered 200 ms later to a separate set of Schaffer/commissural fibers in the CA1 field of rat hippocampal slices. The first (priming) stimulus caused a prolongation of the synaptic response elicited by the second (primed) stimulus. In addition, the priming stimulation facilitated the induction of LTP by bursts of stimulation (4 pulses at 100 Hz) of the second afferent pathway. Analysis of the shape of the synaptic responses indicates that the prolongation is due to the removal of an inhibitory component rather than the addition of a novel excitatory component. Blockade of GABAA-ergic transmission with picrotoxin mimicked the priming effect in that it also widened synaptic responses and facilitated burst-induced LTP. We suggest that these patterns of stimulation result in a transient loss of inhibition during the primed stimulation. This, in turn, brings about a prolongation of the synaptic response that allows short bursts of excitatory synaptic activity to depolarize postsynaptic cells sufficiently to trigger LTP.