The influence of ocular pulsatility on scanning laser Doppler flowmetry.

PURPOSE: To determine the effect of the cardiac cycle on scanning laser Doppler flowmeter measurements of retinal capillary blood flow in rhesus monkeys and humans. METHODS: Multiple scanning laser Doppler flowmetry images of rhesus monkey and human retinal capillary blood flow over a range of heart rates were obtained. Average flow values were determined for the 64 scan lines that compose the two-dimensional flow map. Cutaneous blood flow was measured simultaneously with a laser Doppler flowmeter. The temporal relationships between retinal capillary blood flow, peripheral arterial pulse, and cutaneous blood flow were determined. In addition, human retinal capillary blood flow in a 10 x 10-pixel area during different phases of the cardiac cycle was compared. RESULTS: Regular oscillations in human and rhesus monkey retinal capillary blood flow are evident as alternating bright and dark horizontal bands in scanning laser Doppler flowmetry images. These fluctuations are temporally correlated with cutaneous blood flow. Linear regression of actual vs predicted heart rate based on peaks in retinal capillary flow yielded r = 0.999 in a rhesus monkey and 0.938 in a human. Retinal capillary blood flow in a 10 x 10-pixel area fluctuated as much as 50% depending on the phase of the cardiac cycle. CONCLUSIONS: The alternating bright and dark banding pattern observed in scanning laser Doppler flowmetry scans of retinal capillary blood flow is related to the cardiac pulse. The errors introduced by pulse-related fluctuations in retinal capillary blood flow are significant and must be minimized or corrected for accurate and reproducible measurements of ocular hemodynamics.     

Effects of topical epinephrine on aqueous humor dynamics in the cat

The purpose of this study was to investigate, in cats, the effects of topical epinephrine on aqueous humor dynamics as measured by the non-invasive method of fluorophotometry and by other methods. Measurements were carried out on 12 cats before and after one week of twice daily treatment with 2% epinephrine hydrochloride to one eye. Aqueous flow and outflow facility were determined using fluorophotometry. Uveoscleral outflow was calculated from these results and was evaluated with anterior chamber perfusion of FITC-dextran. Outflow facility also was measured by tonography. Epinephrine-treated eyes, compared with their baseline values, showed a 31% reduction in intraocular pressure (P<0.001), a 23% reduction in aqueous flow (P<0.05), a 60% increase in fluorophotometric outflow facility (P<0.05), and a 43% increase in tonographic outflow facility (P<0.05). Treated eyes, compared with contralateral control eyes, showed a 27% reduction in IOP (P<0.005), a 25% reduction in aqueous flow (P<0.005), a 38% increase in fluorophotometric outflow facility (P<0.05), and a 34% increase in tonographic outflow facility. When evaluated by both fluorophotometry and FITC-dextran tracer methods, epinephrine had no significant effect on uveoscleral outflow. It was concluded that, in cats treated with topical epinephrine twice daily for a week, a reduction in intraocular pressure is induced by an increase in outflow facility and decrease in aqueous flow.     

8—Br—cAMP对人视网膜母细胞瘤HXO—Rb44细胞癌基因的表达效应

目的 研究８－Ｂｒ－ｃＡＭＰ对培养的人视网膜母细胞瘤ＨＸＯ－Ｒｂ４４细胞癌基因表达的效应及其与该细胞生长的关系。方法 ｃ－ｆｏｓ ｍＲＮＡ,Ｎ－ｍｙｃ ｍＲＮＡ及ｐ２１ｒａｓ ｍＲＮＡ均以原位杂交ＲＮＡ斑点印迹技术检测,对繁殖细胞核抗原,ｖ－Ｆｏｓ,Ｎ－Ｍｙｃ和Ｐ＾２１ｒａｓ蛋白表达的免疫反应性则采用免疫组化及收白质斑点印迹技术检测。     

B型超声检查对渗出型老年性黄斑变性的诊断价值

目的:探讨渗出型老年性黄斑变性(Age-related macular degeneration,AMD)的B型超声影象特征。方法:采用NIDEKUS-3300型超声诊断仪,对31例(54只眼)渗出型AMD进行了观察。结果:视网膜色素上皮脱离时,眼内后极部出现膜状弧形回声,光带与眼球壁之间,可见一个梭形透声区;渗出或出血未完全吸收阶段,呈混合性回声;渗出或出血逐渐吸收并为瘢痕组织所替代时,可见实体性小隆起物,强回声,形状似凸透镜或三角形,凸起端指向球后,玻璃体腔面平坦。结论:B型超声在渗出型AMD的诊断、治疗随访观察中具有实用价值。眼科学报1999;15:233-235。     

角膜缘干细胞与结膜移植治疗翼状胬肉

目的:观察角膜缘干细胞与结膜移植治疗翼状胬肉的疗效。方法:采用自体角膜缘干细胞与结膜移植术,对38例43眼初发和复发性翼状胬肉患者进行治疗,术后随访3～30月,平均10月。结果:38例43眼中34例38眼上皮愈合稳定,角膜恢复正常光滑、透明,胬肉无复发。4例5眼失访。结论:自体角膜缘上皮移植为病变区角膜和结膜提供新的干细胞来源,是治疗翼状胬肉的理想方法。眼科学报1999;15:89—90。     

碱性成纤维细胞生长因子在人晶体上皮细胞的蛋白检测研究

研究成纤维细胞生长因子（ｂａｓｉｃｆｉｂｒｏｂｌａｓｔｇｒｏｗｔｈｆａｃｔｏｒ,ｂＦＧＦ）对人晶体上皮细胞（ｈｕｍａｎｌｅｎｓｅｐｉｔｈｅｌｉａｌｃｅｌｓ,ＨＬＥＣｓ）的促增殖作用。方法：采用免疫组织化学检查（ＡＢＣ法）来检测人晶体上皮细胞上ｂＦＧＦ蛋白水平,并用图像分析进行相对定量。结果：定性及定量地证明了人晶体上皮细胞有ｂＦＧＦ蛋白存在。结论：阐明了人晶体上皮细胞本身存在的ｂＦＧＦ以蛋白的形式参与了术后后囊混浊的形成。     

春季结膜炎穹窿结膜的临床病理

证明春季结膜炎在穹窿结膜的临床病理。方法：详细记载球（角膜缘）、睑及穹窿结膜的临床表现;对３８眼（２１例）的穹窿结膜（上穹窿３４眼、下穹窿４眼）进行活检,组织切片ＨＥ染色,光学显微镜下观察病理改变。结果：结膜上皮不同程度增生,上皮下淋巴细胞、浆细胞浸润或胶元纤维增生,３８眼标本中３２眼有嗜酸性白细胞、１眼有嗜碱性白细胞浸润。一极轻病例双眼下穹窿结膜只有很少几个淋巴细胞,其中却散在个别嗜酸性白细胞。结论：春季结膜炎的临床病理改变包括穹窿结膜。     

人眼晶体悬韧带的张力测定

目的:进行人眼晶体悬韧带部位及其张力的测定。　方法:对26只离体尸眼进行测定。悬韧带的最大张力规定为:在其放松及最大伸张情况下,从睫状突到嵌入晶体前囊膜内的悬韧带的距离的差值。　　结果:悬韧带在拉断之前平均能被拉长4.48±1.78mm,年轻组为5.33±1.19mm,老年组为2.17±0.70mm。无韧带区老年组为6.98±0.70mm,年轻组为7.66±0.42mm,平均为7.48±0.58mm。结论:悬韧带具有一定的张力,随着年龄的增长,悬韧带有向囊膜中心生长的趋势,无韧带区随年龄的增加而减小,悬韧带的张力随年龄的增加而减少。     

人眼眩光失能测定及其临床意义

目的:观察国产仪器测定眩光失能的性能与规律,并讨论其临床意义。方法:采用MGT—1多功能视觉眩光测试仪(海军医学研究所研制),按规定方法操作。测定正常人30名56眼(矫正视力全部≥1.0,晶体透明,无其他明显眼病),晶体混浊患者15人27眼。测定目标亮度及眩光亮度设置为中—中及弱—中两档分别模拟白天及夜间眩光失能。结果:中—中状态下,眩光失能值正常人均值为9.22%(全距0～31),低于晶体混浊者(24.05%,全距9～67),两者差异显著。正常眼在弱—中状态眩光失能值较中—中状态明显(均值20.12%,全距0～56)。不同频率条件对正常及晶体混浊眼眩光失能的影响不同,低频及中频较高频区的影响明显。结论:作为视功能评论指标,眩光失能检查是一种实用方法。在眼科临床及人体工效学上具有重要的意义。     

General solution for diffusion-controlled dissolution of spherical particles. 1. Theory.

Three classical particle dissolution rate expressions are commonly used to interpret particle dissolution rate phenomena. Our analysis shows that an assumption used in the derivation of the traditional cube-root law may not be accurate under all conditions for diffusion-controlled particle dissolution. Mathematical analysis shows that the three classical particle dissolution rate expressions are approximate solutions to a general diffusion layer model. The cube-root law is most appropriate when particle size is much larger than the diffusion layer thickness, the two-thirds-root expression applies when the particle size is much smaller than the diffusion layer thickness. The square-root expression is intermediate between these two models. A general solution to the diffusion layer model for monodispersed spherical particles dissolution was derived for sink and nonsink conditions. Constant diffusion layer thickness was assumed in the derivation. Simulated dissolution data showed that the ratio between particle size and diffusion layer thickness (a0/h) is an important factor in controlling the shape of particle dissolution profiles. A new semiempirical general particle dissolution equation is also discussed which encompasses the three classical particle dissolution expressions. The success of the general equation in explaining limitations of traditional particle dissolution expressions demonstrates the usefulness of the general diffusion layer model.