Aims/hypothesis Disruption of the retinal pigment epithelial (RPE) barrier contributes to sub-retinal fluid and retinal oedema as observed in diabetic retinopathy. High placental growth factor (PLGF) vitreous levels have been found in diabetic patients. This work aimed to elucidate the influence of PLGF-1 on a human RPE cell line (ARPE-19) barrier in vitro and on normal rat eyes in vivo. Methods ARPE-19 permeability was measured using transepithelial resistance and inulin flux under stimulation of PLGF-1, vascular endothelial growth factor (VEGF)-E and VEGF165. Using RT-PCR, we evaluated the effect of hypoxic conditions or insulin on transepithelial resistance and on PLGF-1 and VEGF receptors. The involvement of mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK, also known as EPHB2) signalling pathways under PLGF-1 stimulation was evaluated by western blot analysis and specific inhibitors. The effect of PLGF-1 on the external haemato-retinal barrier was evaluated after intravitreous injection of PLGF-1 in the rat eye; evaluation was by semi-thin analysis and zonula occludens-1 immunolocalisation on flat-mounted RPE. Results In vitro, PLGF-1 induced a reversible decrease of transepithelial resistance and enhanced tritiated inulin flux. These effects were specifically abolished by an antisense oligonucleotide directed at VEGF receptor 1. Exposure of ARPE-19 cells to hypoxic conditions or to insulin induced an upregulation of PLGF-1 expression along with increased transcellular permeability. The PLGF-1-induced RPE cell permeability involved the MEK signalling pathway. Injection of PLGF-1 into the rat eye vitreous induced an opening of the RPE tight junctions with subsequent sub-retinal fluid accumulation, retinal oedema and cytoplasmic translocation of junction proteins. Conclusions/interpretation Our results indicate that PLGF-1 may be a potential regulation target for the control of diabetic retinal and macular oedema.

Abstract-Angiotensin II (Ang II) plays essential roles in vascular homeostasis, neointimal formation, and postinfarct remodeling. Although Ang II has been shown to regulate apoptosis in cardiomyocytes and vascular smooth muscle cells, its role in vascular endothelial cells (ECs) remains elusive. To address this issue, we first performed TUNEL and caspase-3 activity assays with porcine microvascular ECs challenged by serum deprivation. Ang II significantly reduced the ratio of apoptotic cells and caspase-3 activity. The Ang II type 1 receptor (AT 1 ) was responsible for these effects. Among the signaling molecules downstream of AT 1 , we revealed that PI3-kinase/Akt pathway plays a predominant role in the antiapoptotic effect of Ang II. Interestingly, the expression of survivin, a central molecule of cell survival, increased after Ang II stimulation. Overexpression of a dominant-negative form of Akt abolished both Ang II-induced antiapoptosis and survivin protein expression. In a murine model of hyperoxygen-induced retinal vascular regression, AT 1a knockout mice showed a significant increase in retinal avascular areas. Our data indicate that Ang II plays a critical antiapoptotic role in vascular ECs by a mechanism involving PI3-kinase/Akt activation, subsequent upregulation of survivin, and suppression of caspase-3 activity. Key Words: angiotensin II Ⅲ apoptosis Ⅲ endothelium Ⅲ survivin Ⅲ caspase-3 A ngiotensin II (Ang II), the most important effector peptide of the renin-angiotensin system, plays central roles in volume and salt homeostasis. Ang II is implicated in cardiovascular and renal pathology including cardiac left ventricular hypertrophy, neointimal formation, postinfarct vascular remodeling, and nephrosclerosis. 1,2 Apoptosis and cellular proliferation are important mechanisms causing these pathological conditions. In this respect, Ang II has been recognized as a growth-promoting and apoptosis-regulating factor contributing to vascular structural alteration. 3 Ang II initiates its effects by interaction with at least two pharmacologically distinct subtypes of cell-surface receptors, AT 1 and AT 2 . In mice, the AT 1 receptor is further subdivided into AT 1a and AT 1b . Major functions of Ang II in the cardiovascular system are mediated through AT 1 , whereas AT 2 exerts antigrowth and antihypertrophic effects. 4 Ang II activates multiple signaling pathways, including protein kinase C (PKC), 5 and mitogen-activated protein kinase (MAPK). 5 MAPKs are key regulatory proteins that control the cellular response to growth, apoptosis, and stress signals. More recently, stimulation of AT 1 has been shown to trigger the activation of phosphatidylinositol 3 (PI3)-kinase and Akt, 6 which is a common feature in the signal transduction of the antiapoptotic effects of growth factors. Although both MAPK and PI3-kinase/Akt contribute to apoptosis, the precise role of Ang II in apoptosis has been a subject of continuing controversy. Ang II has been reported to induce apoptosis in fibroblasts, 7 cardiomyocytes, 8 ...

Transcription factor Ets-1 has been reported to regulate angiogenesis in vascular endothelial cells. Here, we investigated a mechanism that may regulate the expression of Ets-1 in vascular endothelial growth factor (VEGF)- and hypoxia-induced retinal neovascularization and that may have potential to inhibit ocular neovascular diseases. VEGF and hypoxia increased Ets-1 expression in cultured bovine retinal endothelial cells. The VEGF-induced mRNA increase of Ets-1 was suppressed by a tyrosine kinase inhibitor (genistein), by inhibitors of MEK (mitogen-activated protein and extracellular signal-regulated kinase kinase) (PD98059 and UO126), and by inhibitors of protein kinase C (GF109203X, staurosporine, and Gö6976). Dominant-negative Ets-1 inhibited VEGF-induced cell proliferation, tube formation, and the expression of neuropilin-1 and angiopoietin-2. In a mouse model of proliferative retinopathy, Ets-1 mRNA was up-regulated. Intravitreal injection of dominant-negative Ets-1 suppressed retinal angiogenesis in a mouse model of proliferative retinopathy. In conclusion, VEGF induces Ets-1 expression in bovine retinal endothelial cells and its expression is protein kinase C/ERK pathway-dependent. Ets-1 up-regulation is involved in the development of retinal neovascularization, and inhibition of Ets-1 may be beneficial in the treatment of ischemic ocular diseases.

The purpose of this study was to investigate the duration of each series of offensive and defensive techniques and the cardiovascular, metabolic, and perceptual responses during 2- and 3-minute bouts of simulated karate sparring. Six young men (age, 18-20 years) and 6 boys (age, 16-17 years) participated in this study. We formed 3 pairs of men and 3 pairs of boys to create a demanding competitive environment. After a rest period, each pair performed a 2-minute bout of sparring, sat quietly for 60 minutes, and then performed 3-minute bout of sparring. We measured oxygen uptake (Vo2), heart rate (HR), and blood lactate responses and ascertained the rate of perceived exertion (RPE) and energy expenditure (EE) during these sparring bouts. The ventilatory threshold was estimated from ventilatory equivalent and Vo2 obtained during the treadmill test. The duration of each series of offensive and defensive techniques was videotaped. During the 2- and 3-minute bouts of sparring, the duration of longest series of offensive and/or defensive combination techniques performed were 2.1 +/- 1.0 and 1.8 +/- 0.4 seconds, respectively; the mean total times of performing offensive and defensive techniques were 13.3 +/- 3.3 and 19.4 +/- 5.5 seconds, respectively. The mean oxygen uptake (Vo2), the percentage of maximum oxygen uptake (%Vo2max), HR, percentage of maximum HR, RPE, and EE for a 3-minute bout of sparring were significantly higher than for a 2-minute bout of sparring. The mean %Vo2max values for these bouts of sparring were below the ventilatory threshold. It is recommended that karate practitioners perform more specific weight training, plyometric exercises, and interval training to increase the ability to buffer acid muscle and blood concentrations and to build lean body mass, strength, and power to develop the specific motor skills required in sparring.

In DMO, the ELM status may be as closely related to VA as the IS/OS status.

No abstract

23-gauge TSV appears to be as safe and effective as 25-gauge TSV in macular hole surgery.

Imaging of melanin in the eye is important as the melanin is structurally associated with some ocular diseases, such as age-related macular degeneration. Although optical coherence tomography (OCT) cannot distinguish tissues containing the melanin from other tissues intrinsically, polarization-sensitive OCT (PS-OCT) can detect the melanin through spatial depolarization of the backscattered light from the melanin granules. Entropy is one of the depolarization metrics that can be used to detect malanin granules in PS-OCT and valuable quantitative information on ocular tissue abnormalities can be retrived by correlating entropy with the melanin concentration. In this study, we investigate a relationship between the melanin concentration and some depolarization metrics including the entropy, and show that the entropy is linearly proportional to the melanin concentration in double logarithmic scale when noise bias is corrected for the entropy. In addition, we also confirm that the entropy does not depend on the incident state of polarization using the experimental data, which is one of important attributes that depolarization metrics should have. The dependence on the incident state of polarization is also analyzed for other depolarization metrics.