K R Liu

National Taiwan University Hospital, T’ai-pei, Taipei, Taiwan

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Publications (17)23.85 Total impact

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    ABSTRACT: PURPOSE. Cell-mediated collagen gel contraction plays an important role in the pathogenesis of proliferative vitreoretinopathy (PVR). Anti-adhesion therapy has been suggested as a promising strategy in the treatment of PVR. Crovidisin, a snake venom protein isolated from Crotalus viridis, has been shown to bind selectively to collagen and to inhibit collagen-induced platelet aggregation. In the present study, the effectiveness of crovidisin in inhibiting the attachment of retinal pigment epithelial (RPE) cells to collagen, and RPE cell-mediated collagen gel contraction, was evaluated. METHODS. Fluorescein isothiocyanate (FITC)-conjugated crovidisin was prepared and used to evaluate its binding affinity for collagen type I, fibronectin, vitronectin, and laminin. The inhibitory effect of crovidisin on RPE cell-mediated extracellular matrix attachment and collagen gel contraction was evaluated by cell adhesion and type I collagen gel contraction assays. The cytotoxic effect of crovidisin was examined with a cell proliferation assay, using the Alamar blue method. Flavoridin, an Arg-Gly-Asp-containing peptide from viper venom, was used for comparison. RESULTS. FITC-conjugated crovidisin bound selectively to collagen type I with high affinity. It did not bind to other matrix proteins, including fibronectin, vitronectin and laminin, nor to RPE cells. Crovidisin inhibited RPE cell attachment to type I collagen in a dose-dependent manner. This inhibitory effect was enhanced by the presence of flavoridin. Crovidisin also dose-dependently inhibited RPE cell-mediated type I collagen gel contraction. Crovidisin was non-toxic to RPE cells. CONCLUSIONS. Crovidisin, a snake venom-derived collagen-binding protein, possessing an inhibitory activity on RPE cell-collagen interaction and RPE cell-mediated collagen gel contraction, may be a useful tool for studying cell-collagen interaction, and a potential anti-adhesion therapeutic agent for ocular disorders in which cell-collagen interaction is involved, such as PVR.
    Current Eye Research 07/2009; 16(11):1119-1126. DOI:10.1076/ceyr.16.11.1119.5106 · 1.64 Impact Factor
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    ABSTRACT: Bevacizumab is a potent recombinant humanized monoclonal antibody directed against vascular endothelial growth factor (VEGF). The purpose of this study was to evaluate the therapeutic effect of subconjunctival injection of bevacizumab on corneal neovascularization (NV) in different rabbit models. Several rabbit models of corneal NV were used, including (1) a corneal micropocket assay with VEGF pellet, (2) a corneal micropocket assay with basic fibroblast growth factor (b-FGF) pellets, (3) mechanical limbal injury-induced corneal NV, and (4) an alkali-induced model of corneal NV. Subconjunctival injections of bevacizumab (0.25-2.5 mg) were applied twice per week for 2 to 8 weeks. Digital photographs of the cornea were analyzed to determine the length of corneal NV and the area of cornea covered by NV as a percentage of the total corneal area. Immunohistochemical staining with anti-human IgG antibody labeled with Cy3 was used to determine the detection of intracorneal distribution of bevacizumab after injection. Subconjunctival injection of bevacizumab caused significant inhibition of corneal NV formation as measured by length or surface area in all animal models (P<0.05). No significant ocular complications were found. Staining of bevacizumab was found in the corneal stroma for 3 to at least 14 days in the different rabbit models. Subconjunctival injection of bevacizumab is effective in inhibiting corneal NV in several rabbit models. Bevacizumab may diffuse into the corneal stroma and persist for a few days after injection. It may be useful in preventing corneal NV in the acute phase of various kinds of corneal inflammation.
    Investigative ophthalmology & visual science 11/2008; 50(4):1659-65. DOI:10.1167/iovs.08-1997 · 3.40 Impact Factor
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    ABSTRACT: To evaluate the efficacy of intraocular gas tamponade and macular grid laser photocoagulation to manage recurrent macular hole retinal detachment after an initially successful reattachment by gas tamponade in highly myopic eyes. Five patients with high myopia and macular hole retinal detachment were treated by gas tamponade at the initial operation. Gas tamponade and macular grid laser photocoagulation were performed to treat recurrent retinal detachment at the second surgery. Demographic information, anatomic reattachment of the retina, and final visual acuity were studied. Final successful retinal reattachment at the end of follow-up was obtained in all five eyes. Improvement of postoperative visual acuity with respect to preoperative visual acuity was observed in all patients. Intraocular gas tamponade and grid laser photocoagulation in the macula for the management of recurrent macular hole retinal detachment provides good long-term anatomic success and acceptable functional results.
    Ophthalmic Surgery Lasers and Imaging 05/2008; 39(3):186-90. DOI:10.3928/15428877-20080501-03 · 1.32 Impact Factor
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    C M Gremillion · GA Peyman · K R Liu · K S Naguib ·
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    ABSTRACT: We evaluated the use of a heavier-than-water fluorinated silicone oil in the treatment of 30 selected cases of complicated retinal detachment from January 1988 to July 1989. Proliferative vitreoretinopathy grade C-2 or greater accounted for 19 cases, proliferative diabetic retinopathy with traction detachment for two cases, giant retinal tears five, ruptured globe with retinal detachment two, massive choroidal effusion with retinal detachment one, and acute retinal necrosis with retinal detachment one. Initial retinal reattachment was achieved in all cases. Complications included redetachment seven (23%), cataract six (75% of phakic patients), raised intraocular pressure four (13%), hypotony four (13%), keratopathy three (10%), uveitis-synechia formation three (10%), phthisis two (3%), choroidal haemorrhage one (3%), and vitreous haemorrhage one (3%). Postoperative visual acuities with at least six months' follow-up range from no light perception to 20/50, with seven patients (23%) 20/400 or better.
    British Journal of Ophthalmology 12/1990; 74(11):643-6. DOI:10.1136/bjo.74.11.643 · 2.98 Impact Factor
  • K R Liu · G A Peyman · M V Miceli ·
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    ABSTRACT: Fluorosilicone oil, a high specific gravity fluorinated silicone oil, has been recently reevaluated for temporary use in surgery to repair complicated retinal detachments. We evaluated the toxicity of a low-viscosity (300 centistokes) fluorosilicone oil as a vitreous substitute in vitrectomized eyes of albino rabbits. No toxicities could be demonstrated by histopathologic and electroretinographic examinations 6 weeks following surgery. In vitro experiments also showed no toxic effects on cultured retinoblastoma cells. When fluorosilicone oil was injected into the anterior chamber, endothelial cell damage could be seen 2 weeks following injection. Low-viscosity fluorosilicone oil appears to be a safe vitreous substitute for temporary use; it is easily injected and removed, and it maintains adequate surface tension for intraocular tamponade. Because of its relative low viscosity, 300-cst fluorosilicone oil (FS) may be a better vitreous substitute than perfluorocarbon liquids for both intraoperative manipulation of the retina and short-term intraocular tamponade for complicated retinal detachments.
    Ophthalmic surgery 11/1989; 20(10):720-5.
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    K R Liu · G A Peyman · B Khoobehi ·
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    ABSTRACT: The efficacy of intravitreally administered amphotericin B was evaluated. Experimental fungal infections were produced by inoculation of Candida albicans organisms into the vitreous cavities of 46 rabbit eyes. After 72 hr, eight eyes received intravitreal injections of 10 micrograms of free amphotericin B; and ten eyes each received 10 micrograms, 20 micrograms, and 40 micrograms of liposome-bound amphotericin B. The remaining eight eyes served as controls: four eyes received dextrose solution and four eyes received empty liposomes. Histopathologic examination 8 weeks after inoculation showed clear vitreous without retinal damage in groups treated with either 10 micrograms free amphotericin B or 20 micrograms of liposome-bound drug. All eyes in the control group and six eyes (60%) in the group treated with 10 micrograms of liposome-bound amphotericin B developed vitreous abscesses with evidence of fungal infection. In eyes treated with 40 micrograms of liposome-bound amphotericin B, fungal infection was successfully eradicated, but retinal damage was detected in all eyes by light microscopy. It is proposed that a reduced toxicity of intravitreally injected liposome-bound drugs is accompanied by reduced efficacy. In the treatment of fungal endophthalmitis, an increased dosage of liposome-bound amphotericin B (above that dosage of free drug which would be required) is suggested.
    Investigative Ophthalmology &amp Visual Science 08/1989; 30(7):1527-34. · 3.40 Impact Factor
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    ABSTRACT: A 68-year-old white male had a pigmented choroidal tumor associated with progressive loss of vision. Clinical studies with fluorescein angiography and magnetic resonance imaging suggested a diagnosis of choroidal melanoma. Specimens obtained by internal eye wall resection revealed a choroidal nevus.
    International Ophthalmology 08/1989; 13(4):265-8. DOI:10.1007/BF02280086 · 0.55 Impact Factor
  • K R Liu · G A Peyman · S C She · M R Niesman · B Khoobehi ·
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    ABSTRACT: Cytarabine has been demonstrated to be a more potent inhibitor of fibroblast proliferation than fluorouracil. It is, however, more toxic to the retina. We evaluated the ocular toxicity of liposome-encapsulated cytarabine in vitrectomized and nonvitrectomized rabbit eyes by ophthalmic and histopathologic examination. In the vitrectomized group, doses of up to 26 micrograms were nontoxic to the retina. In nonvitrectomized eyes, doses of up to 55 micrograms were nontoxic. Doses of 85 micrograms resulted in loss of ganglion cells and disorganization of photoreceptor cells. The results obtained in this study demonstrated a substantial reduction in ocular toxicity of liposome-encapsulated cytarabine, as compared with a previous study which employed free drug. By virtue of its reduced toxicity, cytarabine in a liposomal vehicle may be of value in the treatment of ocular proliferative disorders.
    Ophthalmic surgery 06/1989; 20(5):358-61.
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    ABSTRACT: Perfluorophenanthrene, a liquid fluorocarbon with a specific gravity approximately twice that of water, potentially offers certain advantages as a vitreous substitute in vitreoretinal surgery. To determine its efficacy and safety we first purified it by chemical methods used in the preparation of experimental blood substitutes to a level at which it was not at all or only minimally toxic to culture-grown retinoblastoma cells. Nineteen of 22 vitrectomized eyes of white New Zealand rabbits injected with this purified perfluorophenanthrene showed satisfactory clinical tolerance. Light and electron microscopy showed minimal or no toxic effects in the 19 eyes, although uptake of perfluorophenanthrene by some preretinal cells was observed 28 days after implantation. Postoperative light-adapted electroretinography recordings of eight of the injected eyes showed no significant change. Perfluorophenanthrene injected into the anterior chamber of the rabbit eyes had toxic effects on the cornea. If further experimentations confirm our findings, perfluorophenanthrene may be a suitable transparent high-density liquid for temporary use in surgery to repair retinal detachments.
    Ophthalmic surgery 05/1989; 20(4):286-93.
  • M E Tawakol · G A Peyman · K R Liu · H E Kaufman ·
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    ABSTRACT: Gore-Tex (polytetrafluoroethylene) grafts have been used in a variety of surgical procedures, particularly vascular, plastic, and reconstructive surgery. As suggested by previous animal studies, Gore-Tex soft tissue patches (expanded polytetrafluoroethylene) may have application in ocular surgery for scleral buckling and support procedures. We buckled the scleras of 14 rabbit eyes using strips of polytetrafluoroethylene soft tissue patches and monitored ocular tissue reaction and histologic changes in response to this material.
    Ophthalmic surgery 04/1989; 20(3):199-201.
  • K R Liu · G A Peyman · J D Myers · S A Hamlin · N Katoh ·
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    ABSTRACT: Two pulsed neodimium yittrium aluminum garnet (Nd:YAG) laser systems were evaluated for contact surgery through a fiberoptic system with a sapphire tip. Pulsed Nd:YAG laser at 1060 nm was as effective as continuous-wave Nd:YAG laser in producing tissue incisions. A combination of 1060-nm and 530-nm wavelengths achieved smooth cutting at lower energy levels. Corneal endothelial cell damage occurred at the high power level (7 watts) required for smooth underwater incisions with both continuous wave and pulsed lasers.
    Japanese Journal of Ophthalmology 02/1989; 33(1):43-56. · 1.68 Impact Factor
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    ABSTRACT: The retinal toxicity of intraocular liposome-bound cyclosporine was studied in albino rabbits by means of electrophysiology and histopathology. During a followup period of one month, no histopathological or electroretinographic changes were noted using concentrations of 100, 200 and 500 micrograms injected intravitreally.
    International Ophthalmology 05/1988; 12(2):105-107. DOI:10.1007/BF00137134 · 0.55 Impact Factor
  • GA Peyman · H C Charles · K R Liu · B Khoobehi · M Niesman ·
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    ABSTRACT: Intravitreal liposome-encapsulated antibiotics and antiviral drugs were used in patients with acute toxoplasmosis retinochoroiditis, presumed propionibacterium acne endophthalmitis after cataract surgery, and presumed cytomegalovirus retinitis associated with AIDS. A single intravitreal dose was effective in the treatment of all the conditions. Intravitreal liposomes may prove to be an advantageous drug delivery system for the treatment of chronic intraocular inflammatory disorders.
    International Ophthalmology 02/1988; 12(3):175-82. DOI:10.1007/BF00130002 · 0.55 Impact Factor
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    ABSTRACT: The concentration of cyclosporine in the vitreous after intravitreal injection of 100 micrograms of either free or liposome-bound cyclosporine was studied in albino rabbits. We found that the half-life of free cyclosporine was about 6 hours and that of liposome-bound cyclosporine was about 3 days. The finding indicates that liposome-bound cyclosporine prolongs the availability of the drug.
    International Ophthalmology 02/1988; 12(2):109-12. DOI:10.1007/BF00137135 · 0.55 Impact Factor
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    ABSTRACT: The concentration of cyclosporine in the aqueous and vitreous humors of albino rabbits was measured, using HPLC at intervals of 24, 48, 96, and 192 hours after subconjunctival injections of 2.5 mg of free or liposome-bound cyclosporine. The aqueous concentration was reasonably high in both groups until day 4: 1050 nanograms per milliliter in the group receiving free cyclosporine, and 1438 nanograms per milliliter in the group receiving liposome-bound cyclosporine. The vitreous concentration was very low in both groups.
    International Ophthalmology 02/1988; 12(2):101-4. DOI:10.1007/BF00137133 · 0.55 Impact Factor
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    ABSTRACT: The effect of both regular silicone and fluorosilicone in preventing retinal detachment caused by experimental proliferative vitreoretinopathy was studied in rabbit eyes which received 250,000 fibroblasts after vitrectomy and lensectomy. In the control group, 14 out of 20 eyes which received fibroblasts had retinal detachments with disorganization of internal structures. In eyes receiving fibroblast and regular silicone, 4 out of 20 eyes had shallow retinal detachment. In the eyes receiving fibroblasts and fluorosilicone, 5 of 28 eyes had shallow retinal detachment. Our findings indicate that both regular silicone and fluorosilicone were effective in preventing retinal detachments caused by experimental proliferative vitreoretinopathy. There was no statistical difference between the two silicone oils.
    International Ophthalmology 02/1988; 11(3):171-4. DOI:10.1007/BF00130619 · 0.55 Impact Factor
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    ABSTRACT: Two groups of albino rabbits received an intravitreal injection of liposome-encapsulated trifluorothymidine. One group underwent a clearance study using high-performance liquid chromatography. The results of this study demonstrated a prolonged vitreal drug level within the range of ID50 for many strains of herpesvirus and human cytomegalovirus (CMV) at 28 days after injection. The eyes of another group were evaluated with preoperative and postoperative indirect ophthalmoscopy, electroretinography, and histologic examination. No retinal toxicity was found.
    Ophthalmology 10/1987; 94(9):1155-9. DOI:10.1016/S0161-6420(87)33325-1 · 6.14 Impact Factor

Publication Stats

355 Citations
23.85 Total Impact Points


  • 1989-2008
    • National Taiwan University Hospital
      T’ai-pei, Taipei, Taiwan
  • 1988-1990
    • Louisiana State University
      Baton Rouge, Louisiana, United States
    • Louisiana State University Health Sciences Center New Orleans
      • Eye Center
      New Orleans, Louisiana, United States
  • 1987
    • University of Illinois at Chicago
      Chicago, Illinois, United States