晶体玻璃体视网膜联合手术治疗复杂性视网膜脱离

目的探讨玻璃体视网膜手术（ｖｉｔｒｅｒｅｔｉｎａｌｓｕｒｇｅｒｙ，ＶＲ术）联合晶体切除／超声粉碎的效果。方法对８１例（８１只眼）应用晶体玻璃体视网膜联合手术（ｌｅｎｔｉｃｕｌａｒ－ｖｉｔｒｅｏｒｅｔｉｎａｌｓｕｒｇｅｒｙ，ＬＶＲ术）治疗的复杂性视网膜脱离进行回顾性分析。结果解剖性成功者６４只眼（７９．０１％），功能性成功者４５只眼（５５．５６％）；手术成功率显著降低的原因是前部增殖性玻璃体视网膜病变（ｐｒｏｌｉｆｅｒａｔｉｖｅｖｉｔｒｅｏ－ｒｅｔｉｎｏｐａｔｈｙ，ＰＶＲ）（成功率４２．８６％，Ｐ＜０．０１）和术中／术后眼内出血（成功率５８．８２％，Ｐ＜０．０２５）。结论ＬＶＲ术是治疗复杂性视网膜脱离的主要方法；显著影响手术预后的因素是前部ＰＶＲ和术中／术后眼内出血。     

Progression of amiodarone induced cataracts

Amiodarone hydrochloride is a potent antiarrhythmic agent recently approved for use by the Food and Drug Administration. Anterior subcapsular lens opacities were observed in seven of fourteen patients treated with moderate to high doses of amiodarone at the Veterans Administration Medical Center in San Francisco in 1982. The present report summarizes the present status of these same fourteen patients ten years later. Anterior subcapsular lens opacities developed or progressed in all patients continuing treatment with this antiarrhythmic agent during the following ten year interval. Although Snellen visual acuities are not decreased, subtle visual impairment is present as measured by contrast sensitivity measurements with and without glare. This decrease in visual acuity is not a contraindication for therapy with this potentially life saving drug.     

碱性成纤维细胞生长因子受体基因在牛眼晶体上皮细胞内的表达

目的探讨碱性成纤维细胞生长因子（ｂａｓｉｃｆｉｂｒｏｂｌａｓｔｇｒｏｗｔｈｆａｃｔｏｒ，ｂＦＧＦ）对晶体上皮细胞促增殖作用的机理。方法从培养的第二代牛眼晶体上皮细胞提取ＲＮＡ，经逆转录反应合成ｃＤＮＡ。借助从人体胎盘纤维细胞ｂＦＧＦ受体序列合成的寡核苷酸引物，聚合酶链反应体外扩增ｃＤＮＡ。扩增的ｃＤＮＡ片段克隆后，Ｓａｎｇｅｒ双脱氧链终止法测定其序列。结果探测出牛眼晶体上皮细胞ｂＦＧＦ受体的ｍＲＮＡ，测序后发现其氨基酸序列片段中仅３个氨基酸与人体不同。结论晶体上皮细胞存在ｂＦＧＦ受体，当ｂＦＧＦ与其受体结合后，对促进晶体上皮细胞的增殖以及白内障术后后囊混浊具有重要作用。     

Impedance of a goat eye lens

The complex electrical impedance of a goat eye lens is studied in the frequency range 10mHz−10Hz at room temperature, using a computer-controlled AC impedance system. AC impedance software (model 368, version 2.2) is employed to determine the total impedance and capacitance of the eye lens at various frequencies. A Cole-Cole plot of the eye lens material is drawn between the real component of impedance Z′ and the imaginary component Z″ for each excitation frequency that shows a perfect arc of a semicircle, with its centre lying below the abscissa at an angle of 35°. The half-angle ϕ between R₀ and R_∞ is found to be 55°, which mathematically demonstrates the selective permeability of the eye lens. Using graphical analysis of the Cole-Cole plot, characteristic frequency f_c and distribution factor α are observed to be 1Hz and 0.77, respectively. At characteristic frequency, capacitance and total impedance are found to be 1.14μF and 9.08kΩ. The effect of electrode polarisation on capacitance is corrected, based on Fricke's power function. The observed electrical parameters are then used to explain the multiple current path through various tissue compartments. Further, an attempt is made to explain the results on the basis of a possible dipolar model.     

The latency of the cat vestibulo-ocular reflex before and after short- and long-term adaptation

Latencies of normal and adapted feline vestibulo-ocular reflex (VOR) were studied in five cats by applying ± 20°/s horizontal head velocity steps (4000°/s₂ acceleration) and measuring the elicited horizontal or vertical reflex eye responses. Normal VOR latency was 13.0 ms ± 1.9 SD. Short-term adaptation was then accomplished by using 2 h of paired horizontal sinusoidal vestibular stimulation and phase-synchronized vertical optokinetic stimulation (cross-axis adaptation). For long-term adaptation, cats wore ×0.25 or ×2.2 magnifying lenses for 4 days. The cats were passively rotated for 2 h/day and allowed to walk freely in the laboratory or their cages for the remainder of the time. The latency of the early (primary) adaptive response was 15.2ms±5.2 SD for crossaxis adaptation and 12.5 ms±3.9 SD for lens adaptation. This short-latency response appeared within 30 min after beginning the adaptation procedure and diminished in magnitude overnight. A late (secondary) adaptive response with latency of 76.8 ms±7.0 SD for cross-axis adaptation and 68.1 ms±8.8 SD for lens adaptation appeared after approximately 2 h of adaptation. It had a more gradual increase in magnitude than the primary response and did not diminish in magnitude overnight. These data suggest that brainstem VOR pathways are a site of learning for adaptive VOR modification, since the primary latency is short and has a similar latency to that of the normal VOR.     

Impedance of goat eye lens at different DC voltages

A computer assisted AC impedance system is used to measure the DC voltage—current (V-I) characteristics and AC impedance of a goat eye lens using a two-probe Ag−AgCl electrode system. The measurement of the V-I characteristics shows that when a DC voltage from 0mV to 30mV is applied, the resultant current decreases from an initial value of 0.58μA to 0.006μA. However, when the voltage is increases beyond 30mV, the current increases and reaches a value of 0.9μA at 100mV. The data on the frequency response (0.01–10 Hz) of the impedance of lens tissue show an inverse relationship with frequency. The effect of various DC voltages, namely 0, 30, 50, 100 and 200 mV, on the impedance of the eye lens is also investigated over a frequency range of 0.01–10 Hz. The measurement results for both V-I characteristics and AC impedance further suggest the presence of a 30 mV voltage compartment in the goat eye lens.     

Clinical evaluation of 430 MHz microwave hyperthermia system with lens applicator for cancer therapy

The clinical efficacy of a microwave (MW) hyperthermia system using an electric-field converging (lens) applicator is evaluated for 42 malignant tumours with a maximum tumour depth of less than 7 cm. The mean of the maximum, average and minimum tumour temperature of the 42 tumours are 44,5, 42.5 and 40.7 C, respectively. The thermal parameters are higher for tumours in the chest, abdominal walls and hip than for those in the neck, groin and extremities. No apparent difference in thermal parameters according to the depth of tumour is shown. Of 40 tumours treated by hyperthermia in combination with radiotherapy, 20 (50%) showed complete regression, 14 (35%) showed partial regression, and six (15%) showed no change. This phase I and II study indicates clinical feasibility of the newly developed MW heating apparatus, and strongly suggests the usefulness of thermoradiotherapy in the treatment of localised superficial and subsurface malignancies.     

Sodium channels in ocular epithelia

Voltage-gated, tetrodotoxin(TTX)-blockable sodium channels are found in most excitable cells and are the primary contributors to action potentials generated by many of these cells. To date, there has only been one report of a non-cultured vertebrate epithelial cell type containing TTX-blockable Na⁺ channels: rabbit non-pigmented ciliary body epithelial cells [Cilluffo MC et al. (1991) Invest Opthalmol Vis Sci 32:1619–1629], and three reports of cultured epithelial cells containing TTX-blockable Na⁺ channels: rabbit non-pigmented and pigmented ciliary body epithelium [Ciluffo MC et al. (1991) Invest Opthalmol Vis Sci 32:1619–1629; Fain GL, Farahbakhsh (1989) J Physiol (Lond) 417:83–103] and human lens epithelium [Cooper K et al. (1990) J Membr Biol 117:285–298]. We report here the presence of sodium currents in two different non-cultured, freshly dissociated transporting epithelial cell types: the rabbit corneal endothelium and the frog lens epithelium. We also report the occurrence of sodium currents in six additional cultured ocular epithelial cell types from three different species. These currents have a current/voltage (I/V) relationship consistent with traditional voltage-gated Na⁺ currents, are quinidine- and TTX-blockable (of the low-affinity TTX-sensitive type), and disappear following bath substitution of Na⁺ with Cs⁺ or K⁺.