视网膜无长突细胞5—HT免疫组织化学研究

用免疫,组织化学ＡＢＣ法研究了５－ＨＴ免疫阳性反应在牛蛙视网膜细胞中的分布。结果人核层内一些无长突细胞及内网层呈阳性反应。根据阳性胞体在内核层的部位和胞体的突起在内网层的分布,鉴别出６种无长突业刑。提示无长突细胞可能在５－ＨＴ信号的传递和调控过程中发挥着重要作用。     

Intravenous Infusion of RMP-7 Increases Ocular Uptake of Ganciclovir

Purpose. The ability of intravenous (i.v.) infusions of the bradykinin agonist, RMP-7, to permeabilize the blood-ocular barriers (BOB) to the antiviral agent ganciclovir was investigated in guinea-pigs. Methods. Different i.v. dosing regimens included pre-treatment with RMP-7 (0.2 g/kg/min for 5 min) followed by either [³H]-ganciclovir (1 Ci/0.2 ml/min) alone, and/or co-infusion with RMP-7 and [³H]-ganciclovir. At specific times the animals were sacrificed, their eyes removed, and the retina and lens epithelium dissected and analyzed for the amount of radioactivity. Results. Using the ratio of tissue vs. integrated plasma radioactivity concentration, a two-fold increase in ganciclovir steady-state levels were observed in the retina as well as lens epithelium following RMP-7 pretreatment. Peak uptake effects were achieved with a 4.5 min ganciclovir infusion. Neither longer infusions of ganciclovir alone, nor co-infusions of RMP-7 and ganciclovir further enhanced the uptake effects. Kinetic analysis indicated that RMP-7 increased the rate of ganciclovir entry (K _IN) in studied ocular tissues, while the efflux of drug (K _OUT) was not affected by this treatment. Finally, ganciclovir retina:plasma ratios elevated by RMP-7 pre-treatment, remained higher than control ratios within 60 min following cessation of 4.5 min ganciclovir infusion. Conclusions. These data offer further evidence that BOB and in particular the blood-retinal barrier can be permeabilized via bradykinin receptor stimulation. As the i.v. infusions of RMP-7 enhanced the retinal uptake of ganciclovir, it is suggested that a combination of RMP-7 and ganciclovir may provide a novel approach for treating cytomegalo-virus retinis.     

高血压大鼠视网膜组织Ca2+-ATP酶组织化学及卡托普利终身治疗的观察

目的探讨高血压视网膜病变的发病机制及卡托普利防治高血压视网膜病的治疗机制. 方法 应用光镜定量酶组织化学方法对正常京都种大鼠(正常组),自发性高血压大鼠(高血压组)和卡托普利终身用药治疗的自发性高血压大鼠(用药组)的视网膜组织的Ca2+-ATP酶的分布和活性进行定量观察. 结果 Ca2+-ATP酶在正常组大鼠视网膜组织中主要分布在杆锥细胞层内节、外核层和节细胞神经纤维层,上述三层Ca2+-ATP酶活性(U/μm2)分别为0.662±0.014, 0.665±0.018和0.525±0.021,在高血压组大鼠视网膜组织中,各层Ca2+-ATP酶活性下降,三层Ca2+-ATP酶活性分别为0.610±0.017, 0.598±0.014和0.481±0.010;在用药组大鼠视网膜组织中,Ca2+-ATP酶活性较高血压组增强,三层Ca2+-ATP酶活性分别为0.650±0.016, 0.650±0.014, 0.519±0.022.结论 Ca2+-ATP酶活性下降,细胞内液Ca2+浓度增加是高血压视网膜病变的原因之一;卡托普利防治高血压视网膜病的机制与增强Ca2+-ATP酶和降低细胞内Ca2+浓度有关.     

牛视网膜提取物对人-鼠杂合细胞抗体产生的影响

目的：探讨牛视网膜提取物对人－鼠杂合细胞抗体产生的影响。方法：在ＰＲＭＩ１６４０完全培养基（ＣＭ）中加入２０ｍｇ／Ｌ牛视网膜提取蛋白,配成牛视网膜培养基（ＢＲＥＭ）。用ＭＴＴ测定、细胞克隆技术、夹心ＥＬＩＳＡ方法和染色体分析,比较人－鼠杂合细胞Ｇ１２在两种培养条件下的细胞活力、克隆效率、人ＩｇＭ分泌和人染色体阳性细胞比率之间的差异。结果：用ＢＲＥＭ培养的Ｇ１２细胞活力高于用ＣＭ培养（Ｐ＜００５）。用ＢＲＥＭ培养的Ｇ１２细胞克隆中分泌人ＩｇＭ者占１２／２４,用ＣＭ培养的克隆只占２／４７。Ｇ１２细胞传代培养３个月后,用ＢＲＥＭ培养的上清人ＩｇＭ水平Ａ４９０为０３３５±００５０,用ＣＭ培养的上清为００７０±００２７（Ｐ＜００５）。前者含人染色体阳性的细胞为２０％,后者２５％,两者间没有差异（Ｐ＞００５）。结论：添加牛视网膜提取物的培养基可以提高人－鼠杂合细胞的活力和人ＩｇＭ抗体的分泌能力。维持人源性ＩｇＭ持续分泌的条件不仅取决于杂合细胞中人染色体的存在和稳定,还有其它未知因素在起作用,牛视网提取蛋白可以提供这方面的需要。     

Pentose shunt activity in developing chick retina and pigment epithelium: A switch in biochemical expression in cultured pigment epithelial cells

Pentose shunt activity in developing chick retina and pigment epithelium was studied by measuring the rate of ¹⁴CO₂ evolution from glucose selectively labelled in the C-1 and C-6 positions. In the retina, shunt activity declines from appreciable levels at stages 29–31 to minimal activity in the 2-week-old hatched chick. Overall retinal metabolism also declines up to stage 45, but dramatically increases again after hatching. Developing chick pigment epithelium has minimal shunt activity at all stages studied. In contrast, cultured chick pigment epithelium has appreciable shunt activity which is constant over a period of several weeks in culture. This appears to be a switch in biochemical differentiation which could form the basis at least in part for subsequent changes in cell types observed in cultured pigment epithelial cells byEguchi and Okada (1973).     

Comparison of cyclic nucleotide and energy metabolism of intact mouse retina in situ and in vitro.

Whole mouse retina in situ contains approximately 1 μm adenosine 3′,5′-monophosphate (cyclic AMP) and about fivefold higher levels of guanosine 3′,5′-monophosphate (cyclic GMP). Light-adapted retinas have only half as much of both cyclic nucleotides as dark-adapted retinas.Both cyclic AMP and cyclic GMP levels are modified substantially when retinas are removed from the eye and incubated in physiologic buffers. Cyclic GMP levels increase in light- and dark-adapted retinas, but a differential concentration is always maintained, and after a few minutes of incubation it is even greater than that in in situ retinas. In contrast, the difference between cyclic AMP levels obvious in in situ light- and dark-adapted retinas is obscured during the initial minutes of incubation by a transient rise of cyclic AMP in light-adapted retinas, but then becomes apparent again when cyclic AMP levels fall after about 15 min of incubation. Cyclic AMP and cyclic GMP levels decrease rapidly when isolated dark-adapted retinas, in vitro, are exposed to light and the decrease is a function of light intensity. In contrast, cyclic GMP but not cyclic AMP levels increase when light-adapted retinas, in vitro, are placed in darkness.Ischemia causes a marked reduction of ATP and P-creatine levels and elevates cyclic AMP levels in light- and dark-adapted retinas, in situ. Ischemia depresses cyclic GMP levels in dark-adapted retinas, in situ, but has no effect in light-adapted retinas. In incubated retinas, oxygen deprivation produced by NaCN also decreases energy reserves; however, its effect on cyclic AMP is qualitatively similar to that in vivo only after 15 min of incubation. NaCN has little or no effect on cyclic GMP levels in isolated retinas.These data indicate that cyclic nucleotide regulation in intact, incubated retina has many similarities to that of retina, in vivo, and suggest that with due precautions retina maintained, in vitro, is a valid and useful experimental model system for biochemical and biophysical investigations.     

Visual performance in the rhesus monkey after exposure to blue light.

Rhesus monkeys trained to perform a visual task (Landolt ring discrimination) were exposed for 1000 sec to known amounts of 441 nm light by means of a 2500 W xenon lamp with narrow bandpass filter. Radiant exposures to the macula of 30 J/cm² did not impair vision, but 60 J/cm² produced a transient loss of 20/20 vision which lasted from 20 to 30 days. A radiant exposure of 90 J/cm² produced a permanent loss of 20/20 vision. These results, in addition to explaining solar retinitis and eclipse blindness, correlate well with the retinal photopathology of the short wavelength photochemical lesion.     

Dependence of the b-wave on the potassium concentration in the isolated superfused rabbit retina

The amplitude of the b-wave of the isolated superfused rabbit retina is drastically reduced with increasing potassium concentration (10 and 20 mM respectively) in the perfusate like in frog retina. These results are in agreement with the idea of the glial origin of the b-wave, but an influence of potassium on synaptic transmission remains a possibility. For these results the conditions for tissue survival are imperative. When the retina was superfused with a plasma saline mixture kept at 35°C, b-wave amplitudes for different preparations varied between 300 V and 900 V and loss of sensitivity was tolerated till 15% in one preparation. The temperature quotient for the amplitude of b-wave was 4–6 between 35° and 25°C, for the peak time about two.