P53蛋白及P21蛋白在视网膜母细胞瘤表达的研究

目的：探讨P53和P21在视网膜母细胞瘤发生中的作用,及其与预后的关系。方法：应用抗人P53,P21抗体,采用链霉素亲生物素蛋白一过氧化霉（SP）免疫组化方法。对30例RB常规石蜡标本进行P53和P21蛋白的测定,结果：P53和P21在RB中的阳性表达率分别为60％和80％,P53的表达与临床分期有关（P＜0．05）,P53和P21的表达均与生存时间有关,P53阳性组生存时间低于P53阴性组（P＜0．05）,P21阳性组生存时间高于P21阴性组（P＜0．01）,P53阳性组的2年生存率低于P53阴性组,而P21阳性组的2年生存率高于P21的阴性组,结论：在RB的发生中P53和P21起着重要的作用,P53和P21的表达可以作为临床预后的一个参考指标。     

P16INK4a和P14ARF蛋白在喉表达及临床意义鳞癌中的

【摘要】目的探讨P16INK4a和P14ARF蛋白在喉鳞状细胞癌组织中的表达及其临床意义。方法采用免疫组织化学EnVision法检测71例喉鳞状细胞癌组织中P16INK4a和P14ARF蛋白的表达。结果71例喉鳞状细胞癌标本中,35例（49．3％）P16INK4a蛋白阴性,29例（40．8％）P14ARF蛋白阴性,15例（21．1％）P16INK4a和P14ARF蛋白表达均阴性。P16INK4a和P14ARF蛋白阴性间无相关性（P〉O．05）。P16INK4a和P14ARF蛋白阴性率均与患者性别、年龄及临床分期无相关性（P〉0．05）。P14ARF蛋白在Ⅰ—Ⅱ期病例中强阳性占阳性比例为41．7％,在Ⅲ～Ⅳ期中强阳性比例为11．1％。结论P16INK4a和P14ARF在喉鳞状细胞癌发生过程中起重要作用,两种蛋白的失活是各自独立的事件。P14ARF蛋白的缺失发生在喉鳞状细胞癌早期。（中国眼耳鼻喉科杂志,2010,10：218—220）     

Expression of P2Y1, P2Y2, P2Y4, and P2Y6 receptor subtypes in the rat retina

PURPOSE: To elucidate the expression pattern of different types of metabotropic P2Y receptors in the adult rat retina. METHODS: Qualitative RT-PCR was used to investigate the expression profile of different P2Y receptor subtypes (P2Y1, P2Y2, P2Y4, and P2Y6), and in situ hybridization studies were performed to show their cellular localization within the retina. Immunohistochemical staining was used to detect the corresponding P2Y proteins (P2Y1, P2Y2, and P2Y4) and their cellular localization. Southern blot analysis and sequencing verified the identity of the P2Y PCR products. RESULTS: RT-PCR revealed the presence of P2Y1, -2, -4, and -6 mRNA in the neural retina and the retinal pigment epithelium (RPE) and choroid. In situ hybridization showed labeling in the retinal ganglion cell layer for all four P2Y receptor subtypes, although the intensity varied. In addition, staining for P2Y1, -4, and -6 mRNA was shown in the inner nuclear layer, but was absent for the P2Y2 receptor subtype. Immunohistochemistry showed intense staining for P2Y1, -2, and -4 in the ganglion cell layer and the outer plexiform layer. There was also a specific subtype staining in the inner plexiform layer (P2Y2, -4), the inner (P2Y1, -4) and outer (P2Y1) nuclear layers and the inner segments of the photoreceptors (P2Y1, -2). discussion. The data suggest that extracellular nucleotides may play complex roles as autocrine-paracrine mediators and may have neuromodulatory effects in the retina through metabotropic P2Y receptors.     

Rod photoreceptor function predicts blood vessel abnormality in retinopathy of prematurity

PURPOSE: To test the hypothesis that early rod dysfunction predicts the blood vessel abnormalities that are the clinical hallmark of retinopathy of prematurity (ROP). METHODS: Two rat models of ROP, induced by exposure to alternating 50%/10% oxygen (50/10 model) from postnatal day (P) 0 to P14, or exposure to 75% oxygen (75 model) from P7 to P14, and controls reared in room air were studied. In a longitudinal design, electroretinographic (ERG) records and digital fundus images were obtained at P20 +/- 1, P30 +/- 1, and P60 +/- 1. Rod sensitivity was derived from the ERG a-wave. Integrated curvature for the arterioles was calculated using Retinal Image multi-Scale Analysis (RISA) software. RESULTS: In both ROP models, rod sensitivity was low at P20. Sensitivity improved by P60 in the 50/10 model, but remained low in the 75 model. Integrated curvature was high at P20 in both ROP models, decreased nearly to normal by P30 in the 50/10 model, but remained high in the 75 model, even at P60. At P20, rod sensitivity correlated with integrated vessel curvature. Furthermore, low rod sensitivity at P20 predicted abnormal retinal vasculature--that is, high integrated curvature--at P30 and P60. In contrast, vessel curvature at P20 did not predict sensitivity at P30 or P60. CONCLUSIONS: The rods may instigate the vascular abnormalities that are the clinical hallmark of ROP.     

小鼠角膜上皮细胞消化培养法和组织块培养法的比较研究

目的:比较小鼠角膜上皮细胞消化培养法和组织块培养法。方法:分别使用消化培养法和组织块培养法培养小鼠角膜上皮细胞。比较两种方法中小鼠角膜上皮细胞的克隆形成率(CFE)和群体倍增(PD)。通过Western blotting方法检测p63、角蛋白19以及角蛋白12的表达。结果:其中80%组织块培养法的原代培养可成功传代,而仅12%的消化培养法原代培养可成功传代;两者比较有显著性差异(P<0.05)。传代培养中,组织块培养法中55%的第一代(P1)细胞可以传代超过P10并继续稳定传代至少可传至P25。而消化培养法传代至P2即不能融合。在P1,组织块培养法细胞的CFE高于消化培养法(P=0·02);而组织块培养法P20细胞的CFE又显著高于其P1细胞(P=0.001)。免疫荧光染色显示消化培养法的P1细胞和组织块培养法的P1,P20细胞均表达p63和K19。K12仅在消化培养法的P1细胞和组织块培养法的P1中表达,而组织块培养法的P20细胞中,K12阴性表达。结论:小鼠角膜上皮细胞的培养,组织块培养法优于消化培养法。     

体外培养不同代角膜缘干细胞特性分析

目的比较不同代角膜缘干细胞的生物学特性,为角膜缘细胞移植在临床中的氉应用提供依据。方法组织块培养法体外培养角膜缘干细胞,光镜观察、HE染色和免疫荧光染色分析原代、第1代和第2代角膜缘细胞形态学特性;流式细胞技术定量检测原代、第1代和第2代角膜缘细胞ABCG2表达;MTT比色法测定体外培养原代、第1代和第2代角膜缘干细胞的增殖活性变化。结果倒置相差显微镜下可见原代细胞培养24h有单个细胞从组织块边缘迁出,48h细胞局部可见拉网样生长趋势,72h出现大片细胞,细胞呈现多边形或多角形,96h细胞几乎铺满整个培养板。随着传代次数的增加,细胞形态变得不规则,CK3单克隆抗体表达阳性率逐渐增强;p63单克隆抗体原代和第1代细胞间表达阳性率无明显差别,第2代细胞表达量明显减弱。流式细胞检测显示原代、第1代和第2代细胞ABCG2表达阳性率分别为13.41%、22.96%和4.43%。MTT结果显示随传代次数增加细胞增殖活性逐渐下降。结论原代和第1代角膜缘干细胞可以作为制备组织工程角膜上皮细胞膜片的较理想种子细胞。     

Association between risk factors and retinal nerve fiber layer loss in early stages of diabetic retinopathy

AIM:To investigate the changes of retinal nerve fiber layer(RNFL)among normal individuals,diabetic patients without diabetic retinopathy(NDR)and non-proliferative diabetic retinopathy(NPDR),and explore the possible risk factors of early diabetic retinopathy(DR).METHODS:In this cross-sectional study,107 participants were divided in three groups.Totally 31 normal individuals(control group),40 diabetic patients without DR(NDR group)and 36 patients with NPDR(NPDR group)were included.Optical coherence tomography(OCT)was used to detect RNFL thickness and other optic disc parameters among different groups.The potential association between RNFL loss and systemic risk factors were assessed for DR,including diabetes duration,body mass index(BMI),hemoglobin A1 c(Hb A1 c),serum lipids,and blood pressure.RESULTS:The average and each quadrant RNFL thickness were thinner in NPDR group compared to control group of the right(P=0.00,P=0.01,P=0.01,P=0.02,P=0.04)and left eyes(P=0.00,P=0.00,P=0.00,P=0.03,P=0.04).The average,superior and inferior RNFL thickness were thinner in NDR group compared to the NPDR group of the right(P=0.00,P=0.02,P=0.03)and left eyes(P=0.00,P=0.00,P=0.01).Diabetic duration was negatively correlated with the superior,inferior,and average RNFL thickness of the right(r=-0.385,P=0.001;r=-0.366,P=0.001;r=-0.503,P=0.000)and left eyes(r=-0.271,P=0.018;r=0.278,P=0.015;r=-0.260,P=0.023).Hb A1 c was negatively correlated with the superior,inferior,and average RNFL thickness of the right(r=-0.316 P=0.005;r=-0.414,P=0.000;r=-0.418,P=0.000)and left eyes(r=-0.367,P=0.001;r=-0.250,P=0.030;r=-0.393,P=0.000).Systolic pressure was negatively correlated with the inferior and average RNFL thickness of the right eye(r=-0.402,P=0.000;r=-0.371,P=0.001)and was negatively correlated with the superior and average RNFL thickness of the left eye(r=-0.264,P=0.021;r=-0.233,P=0.043).CONCLUSION:RNFL loss,especially in the superior and inferior quadrants,may be the earliest structural change of the retina in diabetic patients,and is also associated with diabetic duration,Hb A1 c,and systolic pressure.     

Retrobulbar administration of purified anti-nerve growth factor in developing rats induces structural and biochemical changes in the retina and cornea

AIM:To develop an experimental model of endogenous nerve growth factor(NGF)deprivation by retrobulbar administration of purified neutralizing anti-NGF antibodies in young Sprague-Dawley rats and provide further information on NGF expression in the retina and cornea.METHODS:Sixty old pathogen-free Sprague Dawley rats(p14,post-natal days)were treated with repeated retrobulbar injections of neutralizing anti-NGF(2μL,100μg/m L,every 3 d).After 2 wk(p28),retinal and corneal tissues were investigated for morphological,biochemical,and molecular expression of trkANGFR by using Western blotting or immunofluorescence.Rhodopsin as well as protein profile expression were also investigated.RESULTS:Chronic retrobulbar neutralizing anti-NGF antibodies changed the distribution of trkANGFR immunoreactivity at retinal level,while no changes were detected for global trkANGFR protein expression.By contrary,the treatment resulted in the increase of corneal trkANGFR expression.Retinal tissues showed a decreased rhodopsin expression as well as reduced number of both rhodopsin expressing and total retinal cells,as observed after single cell extraction.A decreased expression of ICAM-1,IL-17 and IL-13 as well as an increased expression of IL-21 typified retinal extracts.No significant changes were observed for corneal tissues.CONCLUSION:The reduced availability of endogenous NGF,as produced by chronic retrobulbar anti-NGF administration,produce a quick response from retinal tissues,with respect to corneal ones,suggesting the presence of early compensatory mechanisms to protect retinal networking.     

Chorioretinal vascular oxygen tension changes in response to light flicker

PURPOSE: To investigate oxygen tension (P(O2)) changes in the retinal and choroidal vasculatures in response to visual stimulation by light flicker. METHODS: A previously developed optical section phosphorescence imaging system was used to measure P(O2) separately in the retinal veins, arteries, and capillaries and in the choroid before and during light flicker. Imaging was performed in rats during light flicker at frequencies between 0 and 14 Hz. Light flicker-induced changes in the chorioretinal vasculature P(O2) and arteriovenous P(O2) differences were determined. Retinal arterial and venous P(O2) were measured along blood vessels as a function of the distance from the optic nerve head. RESULTS: Retinal arterial P(O2) and arteriovenous P(O2) differences increased with increasing light flicker at frequencies up to 10 Hz, after which no further increase was observed. Significant increases in retinal arterial P(O2) (P = 0.009; n =10) and in retinal capillary P(O2) (P = 0.04, n = 10) were measured in response to light flicker at 10 Hz. Retinal arteriovenous P(O2) differences during light flicker were significantly greater than differences before light flicker (P = 0.01; n = 10). Retinal arterial P(O2) decreased significantly with increased distance from the optic nerve head (P < or = 0.004), whereas retinal venous P(O2) remained relatively unchanged (P > or= 0.4). CONCLUSIONS: Measurement of changes in the chorioretinal vasculature P(O2) can potentially advance the understanding of oxygen dynamics in challenged physiological states and in animal models of human retinal diseases.     

毛果芸香碱促进培养的兔泪腺上皮细胞蛋白合成和分泌

目的研究毛果芸香碱对体外培养兔泪腺上皮细胞蛋白分泌与合成的影响。设计实验研究。研究对象培养的兔泪腺上皮细胞。方法对培养细胞进行广谱细胞角蛋白、波形蛋白免疫组化染色及电镜观察鉴定后,培养的兔泪腺上皮细胞中,分别加入700、70、7、0．7和0．07μmol／L的毛果芸香碱,培养24小时,分别测定培养液和细胞中的β－氨基已糖苷酶活性。在不同浓度毛果芸香碱的培养细胞中加入70μmol／L阿托品,培养24小时,分别测定培养液和细胞中的β－氨基已糖苷酶活性。主要指标β－氨基已糖苷酶活胜（光密度值,OD）。结果毛果芸香碱在700、70、7、0．7和0．07μmol／L浓度时使泪腺上皮细胞培养液β－氨基已糖苷酶活性OD值分别增加17．7％（P＝0．015）、14．7％（P＝0．038）、5．7％（P＝0．399）、413％（P=0．517）和2．0％（P=0．7641,使泪腺上皮细胞冻融液β－氨基已糖苷酶活性OD值分别增加25．0％（P=0.000）、16．8％（P＝0．001）、10．6％（P=0．023）、7．6％（P=0．089）和4．8％（P=0．271）。阿托品抑制毛果芸香碱的作用,使泪腺上皮细胞培养液β-氨基已糖苷酶活性OD值分别减少20．5％（P=0．018）、15．1％（P=0．029）、10．1％（P=0．097）、11．5％（P=0．118）和7．9％（P=0．085）,使泪腺上皮细胞冻融液B一氨基已糖苷酶活性OD值分别减少10．0％（P=0．039）、4．8％（P=0．113）、6．2％（P=0．162）、2．9％（P=0．315）和0％（P=0．300）。结论毛果芸香碱可增加培养的泪腺上皮细胞的蛋白分泌和合成,阿托品可抑制毛果芸香碱的作用。     

Properties of the visual pigments of the moth Manduca sexta and the effects of two detergents, digitonin and CHAPS

The three known visual pigments (P520, P450, P357) of the moth, Manduca sexta (Lepidoptera, Sphingidae), were extracted in two different detergents (2% digitonin, 6 or 12mM CHAPS). As is the case in unextracted membranes, the metarhodopsins are quite stable in CHAPS extracts, while in digitonin the metarhodopsins of P520 and P450 decay rapidly at 15° C to opsin and free retinal. The relative absorbance ratios are: 1.0:1.6 (P520:M485), 1.0:1.1 (P450:M485), and 1.0:0.8 (P357:M470). The relative amounts of the visual pigments found in digitonin extracts is 100:25:8 (P520:P450:P357); about 60 picomoles of P520 can be extracted from one Manduca retina.     

米诺环素对视网膜色素变性小鼠光感受器细胞的保护作用

目的 观察米诺环素对视网膜色素变性（RP）的rd小鼠［C3H/HeN (Pde6brd-/rd-)］RP过程的影响。方法 40只新生rd小鼠随机分为10组，5组为实验组，5组为对照组，每组4只小鼠。实验组，出生后每日腹腔注射米诺环素22.5 mg/kg；对照组，出生后每日腹腔注射生理盐水10 ml/kg。在出生后1、7、14、21、28 d各处死一组实验组和对照组小鼠，取眼球做组织学观察并行凋亡细胞检测，并对两组视网膜光感受器细胞数、外核层厚度以及凋亡细胞数目进行统计分析。结果 （1）rd小鼠出生后7 d光感受器细胞开始凋亡，14 d达高峰，28 d光感受器细胞完全消失；（2）出生后7 d实验组光感受器细胞数目和外核层厚度与对照组比较差异无统计学意义；（3）出生后14、21 d实验组光感受器细胞数目和外核层厚度多于对照组相应时间点，差异有统计学意义（14 d：t=-3.03、P=0.016，t=-4.469，P=0.004；21d: t=-8.782、P＜0.001，t=-3.497、P=0.004）；（4）出生后7、14 d实验组外核层凋亡细胞数目少于对照组相应时间点，差异有统计学意义（t=-3.497、P=0.004，t=-8.782、P＜0.0001）。结论 米诺环素在rd小鼠RP早期可以延缓光感受器细胞丢失，但不能完全阻止RP的发生。     

P-糖蛋白及多药耐药相关蛋白在眼眶横纹肌肉瘤中的表达及意义

目的　研究P 糖蛋白(P gp)、多药耐药相关蛋白 (MRP)在眼眶横纹肌肉瘤中的表达及临床意义。 方法　免疫组织化学法检测 42例眼眶横纹肌肉瘤和 10例正常眼眶组织中P gp、MRP的表达。 结果　P gp、MRP在眼眶横纹肌肉瘤组织中的表达阳性率分别为 38 10%和 54 76%,显著高于正常眼眶组织 (P<0 05 );P gp、MRP表达与年龄、性别、组织学类型、分期无关;复发组P gp和MRP的阳性表达率显著高于初发组(P<0 05);两蛋白间未见相关性。 结论　眼眶横纹肌肉瘤组织的多药耐药与P gp、MRP过表达有关,检测P gp、MRP的表达对判断预后有参考价值。     

Distinct P2Y receptor subtypes regulate calcium signaling in human retinal pigment epithelial cells

PURPOSE: Nucleotide signaling plays a role in retinal pigment epithelial (RPE) function, and receptors for nucleotides are potential therapeutic targets for various ocular diseases. The purpose of this study was to investigate the expression of P2Y receptor subtypes in native and cultured human RPE cells. METHODS: Intracellular Ca(2+) levels were monitored using real-time fluorescence imaging in cultured human RPE cells loaded with Fura-2. Expression of P2Y receptors in native and cultured RPE cells was determined by quantitative RT-PCR and Western blot analysis. RESULTS: Adenosine triphosphate (ATP), uridine triphosphate (UTP), adenosine diphosphate (ADP), 2-methylthio ATP (2MeSATP), and uridine diphosphate (UDP) produced concentration-related increases in [Ca(2+)](i) in cultured RPE cells. However, differences between the magnitude and shape of agonist responses were observed. ATP and UTP showed similar response characteristics, including a distinct Ca(2+) influx component. ATP and UTP were equipotent (EC(50), 6 muM) and maximum responses were equivalent, suggesting activation of a P2Y(2) receptor. Maximal responses to ADP and 2MeSATP were equivalent with EC(50)s of 1 muM and 0.3 muM. The P2Y(1) antagonist MRS 2179 (10 muM) inhibited these responses, confirming functional expression of P2Y(1) receptors. The presence of a response to UDP suggested P2Y(6) expression. There was no influx component to P2Y(1)- and P2Y(6)-mediated responses. mRNA for P2Y(1), P2Y(2,) P2Y(4), and P2Y(6) receptor subtypes was found in cultured RPE cells, and for P2Y(1), P2Y(2,) P2Y(4,) P2Y(6), and P2Y(12) it was found in native RPE cells. Expression of P2Y(1), P2Y(2), and P2Y(6) protein was found in native and cultured RPE cells. CONCLUSIONS: These data define the expression profile of P2Y receptors in human RPE and show that different P2Y subtypes control distinct calcium responses in these cells.     

老年性白内障患者术后P300的改变

本文采用Nicolet公司Compect Four电生理仪对30例正常人及年龄匹配的双眼老年性白内障36例分别测定事件相关电位(ERP),发现双眼白内障患者有明显的P_(300)潜时延长.其中随访到20例视力恢复达0.3以上患者於人工晶体术后3～5周内重复测定ERP,与术前做配对t检验,发现术后较术前有明显的 P_(300)潜时缩短(P<0.001)和P_3波幅的显著提高(P<0.05).表明白内障患者术后认知功能的改善与恢复.     

Evolution of E.O.G. following pan retinal photocoagulation (author's transl)

E.O.G. have been performed before and after panretinal photocoagulation (P.R.P.) on 71 eyes with proliferative diabetic retinopathy. After the P.R.P., the L/D raio is abnormal in 100 % of the eyes. Nevertheless, the L/D ratio was already abnormal in 75 % of the eyes and decreased in 12 % of the eyes before the P.R.P. Thus the impairment of E.O.G. resulting from P.R.P. appears to be a relatively slight sacrifice if compared to the benefit of the treatment.     

Transient protective effect of caspase inhibitors in RCS rat

In most retinal degenerations in humans and in animal models, photoreceptor cells die by apoptosis. Although the biochemical features are similar in all apoptotic cells, different molecular events lead the cell to death. In the present study we used a rat model of inherited retinal degeneration, the RCS rats, to investigate the involvement of the proteases, caspases and/or calpains, in photoreceptor apoptosis. In the first experiments, rats were untreated or injected intravitreally at post natal day 27 (P27) with the large broad spectrum caspase inhibitor, ZVAD, the calpain inhibitor, MuhPhe, or with the vehicle, DMSO. Retinal status was evaluated at P35 and P42 by electroretinography, morphometry and apoptotic nuclei detection. DMSO and MuhPhe had no effect on RCS retinas as evidenced by equivalent loss of function and equivalent number of apoptotic cells than in untreated group. ZVAD transiently reduced apoptotic cells and preserved photoreceptor function at P35 but not at P42. These results suggest that caspases but not calpains are involved in retinal degeneration in the RCS. In the second experiments, RCS rats were injected twice at P27 and P35 with ZVAD or DMSO. Although ZVAD-treated retinas were preserved at P35 compared to the DMSO controls, the second injection of ZVAD did not extend the preserving effect to P42. Moreover, a single injection of ZVAD at P35 had no preserving effect at P42. All these data taken together suggest that caspases do not play a pivotal role after P35. In a fourth set of experiments, we used specific caspase inhibitors to elucidate which caspase was activated. The caspase-1/4 inhibitor (YVAD) or the caspase-3/7 inhibitor (DEVD) were injected intravitreally at P27 and retinal status was evaluated at P35 and P42. Electroretinograms and apoptotic nuclei detection demonstrated that YVAD and DEVD preserved photoreceptors at P35 but not at P42. These results suggest that both caspase-1/4 and caspase-3/7 play a major role in the apoptotic pathway between P27 and P35 in retinal degeneration of RCS rats. In this study, we show that 1/ the photoreceptor apoptotic process in the RCS rat involves caspases but not calpains, and 2/ the retinal degeneration seems to be composed of different phases involving different molecular players. Indeed, we have demonstrated that caspases are playing a major role at P35, but not at P42.     

Spatial pattern and temporal evolution of retinal oxygenation response in oxygen-induced retinopathy

PURPOSE: To determine the spatial pattern and temporal evolution of the change in retinal partial oxygen pressure (DeltaPO(2)) associated with a murine oxygen-induced retinopathy (OIR) model of retinal neovascularization (NV). METHODS: On P7, newborn C57BL/6 mice were exposed to 75% oxygen until postnatal day (P)12, followed by recovery in room air until P17 or P34. Control mice remained in room air until P17 or P34. At P17 and P34, functional magnetic resonance imaging (MRI) and a carbogen inhalation challenge was used to measure retinal DeltaPO(2). Retinal avascularity, distance from the optic nerve head to the vascular edge in the peripheral retina, and NV incidence and severity were measured in retinas stained with adenosine diphosphatase (ADPase). RESULTS: In P17 and P34 controls and in P34 OIR animals, retinas were fully vascularized without evidence of NV. In P17 OIR mice, there was a large central retinal capillary-free zone (22% +/- 3% of the entire retinal area, mean +/- SD) and 4 clockhours (range 1-7) of retinal NV at the border of the peripheral vascular and central acapillary retina in 100% (36/36) of the mice. In P17 OIR mice, retinal DeltaPO(2) over the vascularized far peripheral retina was not significantly (P > 0.05) different from the P17 control but was supernormal (P < 0.05) over the central capillary-free retina. However, no differences (P > 0.05) in retinal DeltaPO(2) were found between the P34 control and OIR groups. CONCLUSIONS: A reversible supernormal DeltaPO(2) was found only over the central acapillary retina during the appearance of retinal NV in a mouse OIR model. The present data show the applicability of carbogen-challenge functional MRI to the study of retinal DeltaPO(2) in vivo in eyes that are too small for the use of existing techniques.