Production of canine IFN-gamma in silkworm by recombinant baculovirus and characterization of the product

Canine interferon-gamma (CaIFN-gamma) cDNA was expressed in silkworm by infecting recombinant baculovirus. Western blot analyses revealed that the resulting preparation contained various CaIFN-gamma protein molecules. Genetic engineering of CaIFN-gamma to remove potential glycosylation sites resulted in reduced components of the CaIFN-gamma, suggesting that one cause of this heterogeneity was glycosylation. Nonglycosylated CaIFN-gamma produced in silkworm still had several components that were deleted at the carboxy-terminal end. The major component was the CaIFN-gamma protein truncated 17 or 16 carboxy-terminal amino acid residues. CaIFN-gamma showed antiviral activity, class II major histocompatibility complex (MHC) expression-enhancing activity, and antiproliferation activity on tumor cells.

Single-pulse ultraviolet laser recording of periodically poled structures in polymer thin films

A simple fabrication technique for nonlinear polymeric optical waveguide patterns is introduced based on the two-beam interference method. We determined that the second-order nonlinearity of poled polymer films is erased by single-pulse ultraviolet (UV) laser irradiation. The erasure mechanism for second-order nonlinearity is discussed. To form a periodic structure in an optical polymer waveguide, two types of optical configuration of two-beam interference were arranged, and a single-pulse UV laser was exposed directly onto poled films. We prove that this method provides a simple way to fabricate volume-type and ridge-type periodically poled structures, i.e., chi(2) gratings, from the submicrometer to the millimeter range.

[Development of a case of Mycobacterium avium complex disease from right pleural effusion]

Moist pleurisy in patients with Mycobacterium avium Complex (MAC) is rarer than tuberculosis. We encountered an extremely rare case of MAC disease in a 75-year-old man who initially had only right pleural effusion. Gaffky VII was detected in the pleural effusion, and Mycobacterium avium was identified by culture and PCR. Although administration of antitubercular agents (RFP, INH, EB, and SM) + CAM and thoracic lavage were repeated, the Gaffky persisted strongly. Accordingly, pulmonary decortication and filling of the cavity with an omental flap were performed as surgical treatments. However, fistulas were formed between the remaining empyema cavity and the surgical wounds. Fenestration was also carried out. Postoperatively, centriacinar abnormalities appeared on computed tomography (CT). It has been reported that MAC disease begins with centriacinar abnormalities and the incidence of the lymphatic developmental pattern was low. Tuberculosis (the idiopathic pleuritis type) is considered to be caused this pattern from the primary infection focus. Therefore, the onset of unilateral effusion is extremely rare in patient with MAC disease, suggesting that the lymphatic developmental pattern occurs less frequently in patients with MAC disease. Furthermore, in this case, we speculated that centriacinar abnormalities were the MAC infection foci and could be detected by CT due to surgical invasion.

Photoreceptor-specific expression of platelet-derived growth factor-B results in traction retinal detachment

Expression of platelet-derived growth factor (PDGF)-A and PDGF-B is increased in patients with proliferative retinopathies in which traction retinal detachments occur. Previous studies have demonstrated that increased expression of PDGF-A in the retina of transgenic mice results in retinal gliosis due to proliferation of astrocytes with different retinal phenotypes based on the time of onset and location of the PDGF-A production. In this study, we investigated the effects of PDGF-B in the retina using gain-of-function transgenic mice that express PDGF-B in photoreceptors. These mice show proliferation of astrocytes, pericytes, and, to a lesser extent, endothelial cells, resulting in ectopic cells on the surface and extending into the retina. The sheets of cells exert traction on the retina resulting in traction retinal detachments similar to those seen in humans with proliferative retinopathies. These studies suggest that PDGF-B has more dramatic effects in the retina than PDGF-A, because it acts on additional cell types, in particular on pericytes, which have a highly developed contractile apparatus. These studies in the retina suggest a means that could be used in other tissues throughout the body to achieve graded PDGF effects. They also provide a new model of traction retinal detachment that can be used to investigate new treatments for patients with proliferative retinopathies.

VEGF is major stimulator in model of choroidal neovascularization

PURPOSE

Vascular endothelial growth factor (VEGF) is upregulated by hypoxia and is a major stimulatory factor for retinal neovascularization in ischemic retinopathies such as diabetic retinopathy. This study sought to determine if VEGF is a stimulatory factor in a murine model of choroidal neovascularization (CNV).

METHODS

Mice with laser-induced ruptures in Bruch's membrane were treated with vehicle alone; a drug that inhibits both VEGF and platelet-derived growth factor (PDGF) receptor kinases; a drug that inhibits PDGF, but not VEGF receptor kinase; or genistein, a nonspecific kinase inhibitor. After two weeks, CNV was quantified and compared.

RESULTS

Blockade of phosphorylation by VEGF and PDGF receptors caused dramatic, almost complete inhibition of CNV. Genistein also had an inhibitory effect, but less so than the VEGF/PDGF receptor blocker. Blockade of phosphorylation by PDGF receptors, but not VEGF receptors, had no significant effect on CNV.

CONCLUSIONS

These data and our previous study, which demonstrated that a kinase inhibitor that blocks VEGF and PDGF receptors and several isoforms of protein kinase C causing dramatic inhibition of CNV, suggest that VEGF signaling plays a critical role in the development of CNV in this model. If safety is established, the effect of inhibiting VEGF receptor kinase activity should be investigated in patients with CNV.

Specific cell-mediated cytotoxicity against a virus-infected syngeneic cell line in isogeneic ginbuna crucian carp

In the present study, we attempted to determine whether virus-specific cell-mediated cytotoxicity occurs in fish. Experiments were conducted with clonal ginbuna crucian carp (Carassius auratus langsdorfii) (S3n strain), and the syngeneic cell line (CFS). Two infectious viruses were used: infectious pancreatic necrosis virus (IPNV) and eel virus from America (EVA). Peripheral blood leukocytes, which consisted almost entirely (95%) of lymphocytes and thrombocytes, from S3n ginbuna immunized with virus-infected CFS cells lysed the virus-infected CFS cells (immunogen) more completely than CFS cells infected with a different virus (non-immunogen). This specific cell-mediated cytotoxicity of ginbuna against virus-infected CFS cells was efficiently induced as a result of in vivo secondary immunization. A significant specific cytotoxic activity peaked during 7-10 days after the secondary immunization. In addition, effector cells immunized with IPNV-infected syngeneic cells did not lyse IPNV-infected xenogeneic cells. These results support the hypothesis that fish exhibit specific cytotoxicity against virus-infected cells, resembling the specific cytotoxicites of higher vertebrates.

The total synthesis of piclavines A1-4 and their biological evaluation

The total synthesis of piclavines A1, A2, A3, and A4 has been achieved starting from compound 10 with enantiomeric enhancement. Their biological activities (antibacterial, antimicrobacterial, and antiviral activities and inhibition of cell growth) were evaluated.

Cellular mechanisms of blood-retinal barrier dysfunction in macular edema

PURPOSE

To determine the mechanism of blood-retinal barrier (BRB) dysfunction in human and experimental specimens using immunocytochemistry.

METHODS

Extravascular albumin was localized in clinical specimens and retinas from transgenic mice that overexpress vascular endothelial growth factor (VEGF) in the photoreceptors. Transgenic mouse retinas were also labeled with Griffonia simplicifolia isolectin-B4 (GSA), a lectin that binds to endothelial cells.

RESULTS

The BRB is established by the presence of tight junctions between the retinal vascular endothelial (RVE) cells and the RPE cells and by a paucity of intraendothelial cell vesicles. When BRB breakdown occurs in human ocular disorders such as diabetic retinopathy, retinitis pigmentosa, or cystoid macular edema, staining for extravascular albumin reveals leakage through the tight junctions, an upregulation of intraendothelial vesicles, and permeation of RVE or RPE cells that have undergone degenerative changes. VEGF, in addition to inducing neovascularization (NV), promotes vascular leakage. In VEGF transgenic mice, BRB failure is confined to the outer retina, the area where NV occurs. GSA binds to the luminal and abluminal surfaces of RVE cells in new and established vessels and to intraendothelial vesicles and interendothelial cell junctions in areas of vascular leakage.

CONCLUSION

BRB dysfunction may be mediated by leakage through the tight junctions of RVE or RPE cells, by trans-endothelial vesicular transport, or by permeation of RVE or RPE cells that have undergone degenerative changes. GSA may be a useful marker to assist in recognizing open tight junctions and an increase in intraendothelial cell vesicles, which are indicative of BRB failure.

Effect of age on the relationship between gastric cancer and Helicobacter pylori. Tokyo Research Group of Prevention for Gastric Cancer

Helicobacter pylori is thought to be involved in the pathogenesis of gastric cancer, but the time point at which it produces its effects (critical time) is unknown. We measured the serum level of H. pylori antibody in 787 gastric cancer patients and 1007 controls aged 20 to 69. Odds ratios for different gastric cancer types and stages were determined for each 10-year age class. The overall odds ratio for gastric cancer decreased with age, being 7.0 for those aged 20 - 29, 14.5 for those aged 30 - 39, 9.1 for those aged 40 - 49, 3.5 for those aged 50 - 59, and 1.5 for those aged 60 - 69 (trend in odds ratios: P < 0.01). However, there was no such age-dependent trend for early diffuse-type cancer; the odds ratios were 12.6, 4.0, 7.2, 6.5, and 18.5 respectively (P = 0.29). Early cancer tended to show higher seroprevalence than advanced cancer, especially in older subjects. No significant difference in seroprevalence was observed between diffuse and intestinal cancers within each age-class. Seroreversion must have occurred in the time interval between the critical time and the diagnosis of the cancer, especially in older patients. The age-dependent relationship between H. pylori and gastric cancer may be due to seroreversion, which itself may be independent of age. This age-independence indicates that prolonged exposure to H. pylori does not increase the magnitude of its influence on gastric carcinogenesis. Possible mechanisms through which H. pylori exerts pathogenic effects are continuous inflammation in adulthood and / or irreversible damage to gastric mucosa in childhood or the teenage years.

Teratogenic effects of bis-diamine on early embryonic rat heart: an in vitro study

BACKGROUND

Bis-diamine induces cardiac defects, including conotruncal anomalies in rat embryos when the agent is administered to the mother. To evaluate the teratogenic effects and mechanism of bis-diamine, we performed morphological and immunohistochemical analyses of early rat embryos cultured in medium containing bis-diamine.

METHODS

The embryos were removed from mother rats on gestational day 10.5 and cultured in medium containing 1 mg of bis-diamine for 6 hr. The embryos were then cultured in medium only for another 6, 12, 18, and 42 hr, corresponding to embryonic day (ED) 11.0, 11.25, 11.5, and 12.5, respectively. Some embryos from the same mothers were used as controls and were cultured in medium only for the corresponding periods to the embryos exposed to bis-diamine. Some mother rats were given a single oral dose of 200 mg of bis-diamine on gestational day 10.5. Embryos from these pregnant rats were removed 6 hr after the oral administration of bis-diamine, and were also cultured in medium only for 6, 12, 18, and 42 hr.

RESULTS

No cardiac abnormalities were detected in the controls at any stage of development. Thirty-three of 51 (65%) embryos exposed to bis-diamine and 15 of 20 (75%) embryos removed from bis-diamine-administered mothers showed abnormal cardiac development, including dilated ventricle, elongation of outflow tract, and pericardial defect on ED 11.5. Four of six (67%) embryos exposed to bis-diamine, and five of seven (71%) removed from bis-diamine-administered mothers also presented almost the same cardiac abnormalities on ED 12.5. No cardiac abnormalities were detected in bis-diamine-treated embryos before ED 11.5. In addition, the expression of neural cell adhesion molecule (N-CAM) was examined using immunohistochemical methods. Fewer N-CAM immunoreactive cells were detected in the third and fourth aortic arches in the bis-diamine-treated embryos than in controls on ED 11.5. However, more N-CAM immunoreactive cells were detected in the bis-diamine-treated embryos than in controls on ED 12.5.

CONCLUSIONS

These results suggest that bis-diamine induces cardiac anomalies by delaying the migration of neural crest cells into the heart and by disturbing the proliferation of pericardial precursor during early cardiac development.

Simultaneous process of embossing and poling at elevated temperatures: a simple technique for nonlinear grating formation in polymer films

A simple technique for fabrication of nonlinear gratings in polymer films, based on simultaneous embossing and poling, is proposed and demonstrated. A master grating consisting of a metal electrode with a dielectric die was fabricated and used for repeated embossing of the grating structures into nonlinear optical polymers at elevated temperatures. At the same time, we applied high voltage to the polymer films to induce second-order nonlinearity. The grating profile and the nonlinearity were estimated, as well as the mass productivity of nonlinear gratings.

A microsatellite linkage map of rainbow trout (Oncorhynchus mykiss) characterized by large sex-specific differences in recombination rates

We constructed a genetic linkage map for a tetraploid derivative species, the rainbow trout (Oncorhynchus mykiss), using 191 microsatellite, 3 RAPD, 7 ESMP, and 7 allozyme markers in three backcross families. The linkage map consists of 29 linkage groups with potential arm displacements in the female map due to male-specific pseudolinkage arrangements. Synteny of duplicated microsatellite markers was used to identify and confirm some previously reported pseudolinkage arrangements based upon allozyme markers. Fifteen centromeric regions (20 chromosome arms) were identified with a half-tetrad analysis using gynogenetic diploids. Female map length is approximately 10 M, but this is a large underestimate as many genotyped segments remain unassigned at a LOD threshold of 3.0. Extreme differences in female:male map distances were observed (ratio F:M, 3.25:1). Females had much lower recombination rates (0.14:1) in telomeric regions than males, while recombination rates were much higher in females within regions proximal to the centromere (F:M, 10:1). Quadrivalent formations that appear almost exclusively in males are postulated to account for the observed differences.

BLNK is associated with the CD72/SHP-1/Grb2 complex in the WEHI231 cell line after membrane IgM cross-linking

Tyrosine phosphorylation of CD72 strongly correlates with B cell antigen receptor signals leading to apoptosis. We have previously shown that CD72 carrying two immunoreceptor tyrosine-based inhibition motifs (ITIM) is an in vivo substrate of SHP-1. CD72 forms a complex with SHP-1 and Grb2 via its tyrosine-phosphorylated ITIM when the WEHI231 cell line, which is representative of immature B cells, undergoes apoptosis. The CD72 complex formation was also demonstrated in normal primary B cells, suggesting that the complex formation in apoptotic B cells is a universal mechanism. In this study, we further investigated the molecular components of the CD72 complex in WEHI231 cells in order to understand the molecular mechanism involved in the signaling pathway mediated through the complex. Our experiments demonstrate that BLNK, a recently identified adaptor molecule predominantly expressed in B cells, is associated with the CD72 complex via the Src homology 3 domain(s) of Grb2 in the cell line after membrane IgM (mIgM) engagement. The results suggest that the mIgM-mediated signal strongly correlates with the formation of the CD72 / SHP-1 / Grb2 / BLNK complex.

The formation and involution of optociliary veins during the course of central retinal vein occlusion

BACKGROUND

Formation of collateral pathways by veins on the optic nerve head is sometimes observed during the resolution of a central retinal vein occlusion (CRVO). However, no cases have been reported in which the formation and involution of these collateral pathways were documented during the resolution of a CRVO.

CASE

A 56-year-old man with a nonischemic CRVO was followed over a 10-year period by ophthalmoscopy, fluorescein angiography (FA), and indocyanine green angiography (IA).

OBSERVATIONS

Initial examination revealed only mild arteriosclerosis and the absence of optociliary veins (OCV) in the right eye. Approximately 9 years later, the patient returned with a nonischemic CRVO, and FA demonstrated a prolongation of the retinal circulation time to 12.1 seconds (normal < 11.0 seconds). Monitoring of this patient while undergoing treatment disclosed the development of OCV on the optic nerve head and gradual decrease in the retinal hemorrhage. FA showed that the retinal circulation time was shortening and recovering to normal. IA verified an outflow through the OCV into choroidal veins. Later, ophthalmoscopy showed a narrowing of the diameter of the OCV.

CONCLUSIONS

We suggest that the OCV developed to drain blood from the retinal veins into the vortex veins through choroidal veins to compensate for the slowing of retinal blood outflow. The reperfusion of the central retinal vein was accompanied by the narrowing of the OCV.

Eel WT1 sequence and expression in spontaneous nephroblastomas in Japanese eel

Nephroblastomas spontaneously developing in Japanese eel reared at farms for 5 to 9months after collection from the wild [Masahito et al., Cancer Res., 52 (1992) 2575-2579] were investigated to cast light on the role of Wilms' tumor 1 gene (WT1) in eel kidney tumorigenesis. Cloning of the WT1 counterpart, EWT1, revealed that conservation of an alternative splice II site, located between the third and fourth zinc fingers, was conserved. The zinc finger domain was highly conserved. The transregulator region, sequences corresponding to exons 4 and 5 in WT1, were lacking in EWT1 cDNA. EWT1 was found to be expressed in kidney, testis and spleen and in situ hybridization revealed dark-stained immature cells in elver kidney to be positive. Although no EWT1 gene mutations were found in 38 eel nephroblastomas, 26 polymorphic nucleic acid changes were observed. Aberrant WT1 expression was noted in epithelial (12 out of 27; 44%) and nephroblastic cell histological types (three out of five; 60%) of eel nephroblastomas. On in situ hybridization the EWT1 expressive cells resembled human blastema cells, similar to those in human Wilms' tumor. These data demonstrated strong signals that the EWT1 protein may function in the development of eel kidney and play a role in genesis of nephroblastomas as in mammals.

The B cell-restricted adaptor BASH is required for normal development and antigen receptor-mediated activation of B cells

B cell antigen receptor signals development, activation, proliferation, or apoptosis of B cells depending on their condition, and its proper signaling is critical for activation and homeostasis of the immune system. The B cell-restricted adaptor protein BASH (also termed BLNK/SLP-65) is rapidly phosphorylated by the tyrosine kinase Syk after BCR ligation and binds to various signaling proteins. BASH structurally resembles SLP-76, which is essential for T cell development and T cell receptor signaling. To evaluate the role for BASH in B cell development and function in vivo, we disrupted BASH alleles in embryonic stem cells by means of homologous recombination and used these cells to complement lymphocyte-incompetent blastocysts from RAG2-deficient mice. In the resultant chimeric mice, T cell development was apparently normal, but B cell development was impaired, and a normally rare population of large preB cells expressing preB cell receptor dominated in the bone marrow in place of small preB cells, although they were mostly noncycling. In addition, the mature B cell populations in the periphery and the bone marrow profoundly decreased in size, as did B-1 cells in the peritoneal cavity, and serum Ig was severely reduced. The BASH-deficient B cells scarcely proliferated or up-regulated B7-2 in response to BCR ligation and poorly proliferated upon CD40 ligation or lipopolysaccharide stimulation. This phenotype indicates that BASH is critical for preB cell receptor signaling inducing proliferation of large preB cells and the following differentiation, for peripheral B cell maturation, and for BCR signaling inducing activation/proliferation of B cells.

Determination of heterogeneous transcription start points of two c-myc genes from the common carp (Cyprinus carpio)

We determined the heterogeneous transcription start points (tsp) of two c-myc genes from the common carp (Cyprinus carpio), tetraploid teleost, by the oligo-capping method and showed the existence of the first exon. This is the first report on the existence of the first exons of the fish c-myc gene. Transcription of the two carp c-myc genes started from at least four sites in CAM1, locating from -752 to -381bp upstream of the translation start site, and from 12 sites in CAM2, locating from -586 to -413bp upstream respectively. The first introns of CAM1 and CAM2 were deduced to be 335 and 356bp, respectively. They shared 86.9% nt identity, lower than those of the second exons (94.1%), and third exons (92.3%), which suggest that the first exons evolved faster. No nt identities were found between the c-myc first exons of carp and other vertebrates. The putative promoter regions in CAM1 and CAM2 contained no obvious TATA or CCAAT boxes in the expected positions.

Molecular cloning of fresh water and deep-sea rod opsin genes from Japanese eel Anguilla japonica and expressional analyses during sexual maturation

We have determined the complete cDNA sequences of fresh water rod opsin gene (fwo) and deep-sea rod opsin gene (dso) from Japanese eel Anguilla japonica. The cDNA clones of fwo and dso consisted of 1437 and 1497 nucleotides, respectively. The predicted opsins of both genes consisted of 352 amino acid residues. Southern blot and PCR analyses of genomic DNA indicated that the Japanese eel genome contains only one fwo and one dso and they are intronless. Quantitative RT-PCR analyses revealed that the expression of fwo decreases with sexual maturation while that of dso increases.

Platelet-derived growth factor-A-induced retinal gliosis protects against ischemic retinopathy

Retinal astrocytes are located in the nerve fiber layer and along retinal blood vessels and have been hypothesized to participate in the induction and maintenance of the blood-retinal barrier. Platelet-derived growth factor-A (PDGF-A) is normally produced by retinal ganglion cells and is involved in astrocyte recruitment and proliferation. We used gain-of-function transgenic mice that express PDGF-A in photoreceptors to explore the roles of PDGF-A and astrocytes in the retina. Transgene-positive mice developed glial infiltration of the inner retina and had significantly less oxygen-induced retinal vascular closure and no neovascularization compared with littermate controls, which had prominent vascular closure and neovascularization. The increased survival of endothelial cells in transgenic mice in the face of oxygen-induced down-regulation of vascular endothelial growth factor was accompanied by an increase in astrocyte-derived fibroblast growth factor-2. Therefore, PDGF-A increases retinal astrocytes, which promote the survival of endothelial cells as well as their expression of barrier characteristics.

Bone morphogenetic proteins-2 and -4: negative growth regulators in adult retinal pigmented epithelium

PURPOSE

To determine the relative level and localization of bone morphogenetic protein (BMP-4 mRNA in the retina and retinal pigmented epithelium (RPE) under normal and pathologic conditions, to seek clues regarding possible functions.

METHODS

Clones isolated from an RPE cDNA library were sequenced and used as probes for northern blot analysis. Expression in the retina and RPE was investigated in mouse models using reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization. The effect of recombinant proteins on RPE proliferation was investigated by thymidine incorporation.

RESULTS

Bovine clones with high homology to BMP-2 and BMP4 were isolated from a subtracted RPE cDNA library. Northern blot analysis using the clones as probes demonstrated abundant and differential expression in adult bovine RPE, but with RT-PCR and in situ hybridization, expression was also demonstrated in mouse retinal neurons. In mice with oxygen-induced ischemic retinopathy there was a striking decrease in BMP-4 mRNA in the retina within 6 hours of the onset of hypoxia that was maintained for at least 5 days. In mice with inherited photoreceptor degeneration, there was a dramatic decrease in BMP4 mRNA in retina and RPE during and after the degeneration. mRNA for the type II BMP receptor was observed in freshly isolated and cultured RPE cells, isolated retina, and freshly isolated bovine aortic endothelial cells. Thymidine incorporation in early-passage RPE cells showed a 14-fold stimulation above control with 5% serum that was decreased to 322%, 393%, and 313% in the presence of BMP-2 (10 ng/ml), BMP4 (10 ng/ml), and transforming growth factor (TGF)-,1 (2 ng/ml), respectively.

CONCLUSIONS

BMP-2 and BMP-4 may serve as negative growth regulators in the retina and RPE that are downregulated by injury, to allow tissue repair. Modulation of expression of the BMPs may provide a means to control the exaggerated wound repair that occurs in proliferative retinopathies.

Blockade of vascular endothelial cell growth factor receptor signaling is sufficient to completely prevent retinal neovascularization

Retinal vasculogenesis and ischemic retinopathies provide good model systems for study of vascular development and neovascularization (NV), respectively. Vascular endothelial cell growth factor (VEGF) has been implicated in the pathogenesis of retinal vasculogenesis and in the development of retinal NV in ischemic retinopathies. However, insulin-like growth factor-I and possibly other growth factors also participate in the development of retinal NV and intraocular injections of VEGF antagonists only partially inhibit retinal NV. One possible conclusion from these studies is that it is necessary to block other growth factors in addition to VEGF to achieve complete inhibition of retinal NV. We recently demonstrated that a partially selective kinase inhibitor, PKC412, that blocks phosphorylation by VEGF and platelet-derived growth factor (PDGF) receptors and several isoforms of protein kinase C (PKC), completely inhibits retinal NV. In this study, we have used three additional selective kinase inhibitors with different selectivity profiles to explore the signaling pathways involved in retinal NV. PTK787, a drug that blocks phosphorylation by VEGF and PDGF receptors, but not PKC, completely inhibited retinal NV in murine oxygen-induced ischemic retinopathy and partially inhibited retinal vascularization during development. CGP 57148 and CGP 53716, two drugs that block phosphorylation by PDGF receptors, but not VEGF receptors, had no significant effect on retinal NV. These data and our previously published study suggest that regardless of contributions by other growth factors, VEGF signaling plays a critical role in the pathogenesis of retinal NV. Inhibition of VEGF receptor kinase activity completely blocks retinal NV and is an excellent target for treatment of proliferative diabetic retinopathy and other ischemic retinopathies.