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J V Forrester

Publications and source records attributed to J V Forrester.

At least 37 records · Page 2Linked to original sources
PubMed2002

True colour imaging of the fundus using a scanning laser ophthalmoscope.

Currently retinal imaging is performed with the fundus camera. This has a number of limitations, in particular the high level of illuminations required for imaging. The scanning laser ophthalmoscope (SLO) has been proposed as an alternative imaging device but to date one of its main limitations has been that it gives only monochromatic images. In this paper we describe an SLO which uses low power red, green and blue lasers to image the human fundus. Using three lasers simultaneously to produce a colour image will increase the fundus exposure by a factor of three. To overcome this problem, a technique has been developed for multiplexing the lasers so that each point on the retina is imaged by the three lasers pulsed rapidly in sequence. The total exposure is thus kept to the same level as for a single laser and total imaging time is not increased. An example is shown of the image from a patient with diabetic retinopathy.

Calibration↗
PubMed2002

Evaluation of corneal graft rejection in a mouse model.

Corneal graft rejection presents clinically and in experimental models as opacification and is considered to be the result of endothelial cell dysfunction or loss. However, recovery from opacification can occur suggesting either (a) that new endothelial cells can regenerate if the original cells were lost, or (b) that sufficient numbers of original cells can regain function if the opacification was due to temporary dysfunction. In this perspective, previous experimental studies of allograft rejection plus some new data are reviewed to support the latter mechanism.

Animals↗
PubMed2001

Kinetics of leukocyte and myeloid cell traffic in the murine corneal allograft response.

BACKGROUND: Little information exists on the trafficking of myeloid and lymphoid cells between the transplanted cornea and the secondary lymphoid tissue. This study reports on changes in the cornea and the draining lymph node (DLN) from the time of graft emplacement. METHODS: Using a mouse corneal graft model (C57BL/10Sn to BALB/c), eyes and submandibular DLN were examined by immunohistochemistry and three-color flow cytometry for evidence of T cell activation and dendritic cell (DC) conditioning (up-regulation of costimulatory molecules) at various times (15 min to 24 days; n=4 for each time). RESULTS: In the DLN, early (2 hr) DC conditioning was sustained throughout allograft rejection whereas a remarkable drop in percentage of activated CD4+ and CD8+ T cells (P <0.001) was followed by a biphasic rise in activated CD4+ and, to a lesser extent, CD8+ T cells (24 hr, P <0.001 and 6 days, P <0.01). CD11b+ and MOMA-2+ macrophages, MHC Class II+ cells, CD86+ DC, and neutrophils were the earliest cells infiltrating the cornea (at 24 hr), whereas T cells appeared after 2 days, with CD4+ T cells being confined largely to the graft recipient border. CONCLUSIONS: Immediate and rapid changes in T cell and DC populations in the DLN correlate with the type of cellular infiltration in the corneal graft. The data are consistent with a model in which CD4+ T cell help for CD8+ cytotoxic T cells could be provided by sequential two-way activation of T cells and DC in the DLN. The majority of cells infiltrating the graft were macrophages and neutrophils, with fewer DC and T cells.

Animals↗
PubMed2001

Regulation of granulocyte-macrophage colony-stimulating factor in human retinal pigment epithelial cells by IL-1beta and IFN-gamma.

GM-CSF production by RPE cells, which form part of the blood-retina barrier, is upregulated by IL-1beta and this increase can be reversed by IFN-gamma. IL-1beta up-regulation is not dependent on PKC but the PKC activator PMA induces low levels of GM-CSF production and acts synergistically with IL-1beta to further increase GM-CSF. Although A23187 and ionomycin stimulated low levels of GM-CSF production, the IL-1beta pathway was cyclosporin A insensitive and did not interact with the calcium pathway. IL-1beta-stimulated GM-CSF mRNA expression and production was strongly dependent on NF-kappaB. IFN-gamma inhibition of the GM-CSF response to IL-1beta acted via NF-kappaB, reducing the translocation of NF-kappaB to the nuclei of RPE cells treated with IL-1beta and IFN-gamma. The results show that IFN-gamma down-regulation acts either directly on NF-kappaB or its activation or by blockade of a pathway upstream of NF-kappaB. However, any such blockade does not involve PKC or intracellular calcium.

Calcium Signaling↗
PubMed2001

Clinical investigation of a true color scanning laser ophthalmoscope.

OBJECTIVE: To show true color scanning laser ophthalmoscope (SLO) images produced by simultaneously imaging the retina with red, green, and blue lasers. METHODS: Low-power red, green, and blue lasers were combined using fiber optics. By rapidly pulsing the lasers, each point on the fundus is illuminated by the 3 colors in quick succession, with the total power level being similar to that from a single laser. The reflected light is then decoded to extract the red, green, and blue color information and the true color fundus image is displayed live on a computer monitor. RESULTS: Comparison was made between the color SLO images from 5 patients and their digitized fundus photographs. The background fundus and retinal vasculature showed a similar appearance. The SLO gave better quality information in patients with ocular histoplasmosis, macular dystrophy, and optic disc drusen. By operating the color SLO in the indirect mode, macular edema could be clearly seen as lines and ridges surrounding the fovea. CONCLUSION: The color SLO offers all the advantages of the present commercially available monochromatic device, with the added advantage of true color representation of the fundus without increasing either imaging time or the level of exposure.

Adult↗
PubMed2001

Immunogenetics and clinical phenotype of sympathetic ophthalmia in British and Irish patients.

BACKGROUND/AIMS: Sympathetic ophthalmia (SO) is a classic example of autoimmune disease where human leucocyte antigen (HLA) genomic associations could provide further understanding of mechanisms of disease. This study sought to assess HLA genetic polymorphism in British and Irish patients with SO, and to assess whether HLA gene variants are associated with clinical phenotype or disease severity. METHODS: High resolution DNA based HLA typing using polymerase chain reaction sequence specific primers was performed in 27 patients with SO and 51 matched healthy controls. Clinical phenotype and markers of disease severity were determined prospectively in 17 newly diagnosed patients and from medical record review and repeat clinical examination in 10 previously diagnosed patients. RESULTS: HLA-Cw*03 (p=0.008), DRB1*04 (p=0.017), and DQA1*03 (p=0.014) were significantly associated with SO. For class II alleles at higher resolution, only HLA-DRB1*0404 (relative risk (RR) = 5.6, p = 0.045) was significantly associated with SO. The highest relative risk for any of the associated haplotypes was with HLA-DRB1*0404-DQA1*0301 (RR=10.9, p=0.019). Patients with the DRB1*04-DQA1*03 associated haplotype were significantly more likely to develop SO earlier, with fewer inciting ocular trauma events, and to require more systemic steroid therapy to control inflammatory activity. CONCLUSIONS: Sympathetic ophthalmia is associated with HLA-DRB1*04 and DQA1*03 genotypes in white patients, similar to Japanese patients. Differences in DRB1*04 gene variant associations (-0404 in Britain and Ireland and -0405 in Japan) may have implications for HLA peptide binding in disease initiation. The DRB1*04-DQA1*03 haplotype is a marker of increased SO susceptibility and severity, as in Vogt-Koyanagi-Harada disease, which also has similar clinicopathological and HLA associations.

Alleles↗
PubMed2001

Psychiatric sequelae and psychosocial adjustment following ocular trauma: a retrospective pilot study.

AIMS: To identify the prevalence of psychiatric and adjustment problems after ocular trauma and those factors related to a poor outcome. METHODS: 47 patients were assessed by structured interview, of whom 45 satisfactorily completed three standardised self report measures of psychological functioning, subjective distress, and social adjustment. RESULTS: 33% of patients displayed psychiatric "caseness". A number of features of the victim consistently resulted in poor outcome including a psychiatric history and peritraumatic dissociation. CONCLUSION: These preliminary findings suggest ocular trauma is associated with psychomorbidity and problems of adjustment. The improved management of such patients would benefit from a more detailed analysis by means of a longitudinal study involving larger samples.

Adaptation, Psychological↗
PubMed2001

Total dose and frequency of administration critically affect success of nasal mucosal tolerance induction.

AIMS: Nasal tolerance induction with autoantigens can effectively protect against a variety of experimental models of autoimmune disease. The aims of this study were to characterise the dosage and kinetics of inhibition of experimental autoimmune uveoretinitis (EAU) via intranasal administration of the uveitogenic antigen interphotoreceptor retinal binding protein (IRBP) in the murine model of IRBP induced EAU. METHODS: B10RIII mice were tolerised by intranasal administration of IRBP either with a long term multiple low dose or a short term/high dosing regimen before subcutaneous immunisation with IRBP in complete Freund's adjuvant (CFA). On day 15 post-immunisation, mice were killed and eyes were removed for histological examination and quantification of inflammatory cell infiltration and degree of target organ (rod outer segment, ROS) destruction. RESULTS: Nasal administration of multiple low doses of IRBP (1 microg or 3 microg IRBP per mouse per day for 10 days) significantly protected mice from IRBP induced EAU. Short term/high dose regimens were only effective when given either as a single or, at most, as two consecutive doses (40 microg per dose). Multiple doses in the range of 45-120 microg over 3 days afforded no protection. CONCLUSIONS: These results indicate that both dose and frequency of intranasal antigen administration are pivotal to tolerance induction and subsequent suppression of T cell mediated autoimmune disease.

Administration, Intranasal↗
PubMed2001

Ex vivo adenovirus mediated gene transfection of human conjunctival epithelium.

AIM: To investigate the efficacy of "ex vivo" adenoviral vector mediated gene transfection of human conjunctival epithelial cell as a possible route for gene therapy for the distribution of anti-inflammatory agents for the potential treatment of immune mediated ocular inflammatory disorders. METHODS: Human conjunctival cells (HCs) were cultured with various concentrations of recombinant adenoviral vectors carrying a reporter gene LacZ, GFP, or an immunomodulating cytokine vIL-10. vIL-10 in culture supernatant was detected by sandwich ELISA and biological activity was assessed by suppression of ConA stimulated splenocyte proliferation. X-gal and GFP expression was assessed by histochemistry. RESULTS: The extent of adenoviral vector mediated transfer of both reporter genes and vIL-10 was dose dependent. LacZ expression could be detected for at least 50 day after infection with multiple of infection (MOI) 200. Following AdCMVvIL-10 transduction, vIL-10 protein expression occurred between 4-6 days post-transduction, and was maintained at a detectable level for at least 1 month. Secreted vIL-10 showed biological activity, significantly inhibiting Con A induced splenocyte proliferation. Additionally, transfection of HCs with two Adv vectors, one carrying LacZ and the other carrying GFP, resulted in co-expression within a single cell. CONCLUSION: These results confirm previous successful adenoviral vector mediated gene transfer to HCs and further show that expression can be maintained. Furthermore the data show HCs can secrete biologically active vIL-10 that could be developed as a strategy to suppress immune mediated disorders. The successful co-transduction of HCs as described for other tissues, opens avenues to develop a multiple target gene therapy locally.

Adenoviridae↗
PubMed2001

Distribution of OX2 antigen and OX2 receptor within retina.

PURPOSE: OX2 is a member of the immunoglobulin superfamily expressed on a broad range of tissues including neurons of the central and peripheral nervous systems, thymocytes, and endothelium. The recently identified OX2 receptor (OX2R) is restricted to the surfaces of myeloid lineage cells, including microglia. Functional data have implicated the OX2-OX2R interaction as a myeloid downregulatory signal. The purpose of this study was to determine the distribution and extent of expression of OX2 and its receptor within the retina, a tissue developed to restrain immune-mediated inflammatory damage. METHODS: OX2 and OX2R monoclonal antibodies (mAbs) were used to determine OX2 and OX2R protein expression, respectively, by flow cytometry of isolated myeloid-derived cells from normal and inflamed rat retina and by immunohistochemistry of serial sections of rat retina. For comparison, distribution of OX2 was documented using species-specific monoclonal antibodies in mouse and human retina. No OX2R mAbs are available for mouse or human detection. RESULTS: OX2 was expressed on retinal vascular endothelium and glial fibrillary acidic protein (GFAP)-negative neurons in retina and optic nerve and on a subpopulation of CD45(+) perivascular and juxtavascular cells. Within normal retina, OX2R was not detected on myeloid-derived cells. During experimental autoimmune uveoretinitis (EAU), expression of both OX2 and OX2R was noted on infiltrating leukocytes. CONCLUSIONS: Taking these results of the distribution of OX2 in normal and OX2R in inflamed retina with other functional data of OX2-OX2R interaction, it is suggested that the OX2-OX2R interaction has the potential to contribute to a novel pathway that suppresses and limits immunologic inflammatory damage within the retina.

Animals↗
PubMed2001

IL-18 not required for IRBP peptide-induced EAU: studies in gene-deficient mice.

PURPOSE: Interleukin (IL)-18 has been described as a proinflammatory cytokine in rheumatoid arthritis and bacterial infectious diseases. The present study was designed to determine the role of IL-18 in a model of ocular experimental autoimmune uveitis (EAU). The initial studies were conducted to detect the expression of IL-18 in normal mouse eye tissue, and the later studies investigated induction of EAU in mice with an IL-18(-/-) phenotype. METHODS: IL-18 detection was performed by using 5-bromo-4-chloro-3-indoyl-ss--D-galactopyranoside (X-Gal) staining on frozen sections of eyes from mice (129/CD1, DBA1, and Balb/c), either of normal phenotype (+/+) or of deficiency (+/-, -/-) in the IL-18 gene which had been replaced by introduced genes including LacZ under the control of an IL-18 promotor. Severity of EAU was assessed in DBA1 and 129/CD1 wild-type (WT) or IL-18 knockout (KO) mice after immunization with the uveitogenic antigen: interphotoreceptor retinal binding protein (IRBP) peptide 161-180. Lymphocyte proliferation and cytokine production were also measured in WT and IL-18 KO DBA1 mice 15 days after immunization. RESULTS: IL-18 is constitutively expressed in the epithelial cells in iris, ciliary body, and retina. EAU-resistant mice (129/CD1) with an IL-18(-/-) phenotype remained resistant after immunization with IRBP peptide (P161-180). However, EAU-susceptible mice (DBA1) exhibited disease with similar histologic characteristics, despite a generalized reduction of interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha on an IL-18(-/-) phenotype. DBA1 IL-18(-/-) also demonstrated reduced IL-10 production. CONCLUSIONS: The IL-18 gene is not necessary for the initiation or pathogenesis of EAU induced by IRBP peptide 161-180. IL-18 is expressed in the epithelial cells in iris, ciliary body, and retina in the eyes, but its role in the eye remains undetermined.

Animals↗
PubMed2001

CD69 expression on peripheral CD4+ T cells parallels disease activity and is reduced by mycophenolate mofetil therapy in uveitis.

PURPOSE: To assess the effects of mycophenolate mofetil (MMF) therapy on T helper cell activation status, using CD69 expression and cytokine profile with flow cytometry in relation to clinical activity in uveitis. METHODS: Patients with posterior or intermediate uveitis treated with MMF (n = 10), patients with active uveitis not treated with MMF and receiving no or minimal therapy (n = 10), and healthy volunteers (n = 21) had peripheral blood lymphocyte immunofluorescence analysis for T helper cell (CD4, CD3) markers, activation status (CD69), and intracellular cytokine (interleukin [IL]-2, interferon [IFN]-gamma, and IL-4) levels. Patients were compared before and during MMF therapy in relation to T helper cell activation and clinical activity. RESULTS: Patients with active uveitis not treated with MMF and receiving no or minimal therapy had increased frequency of CD69-positive CD4 T cells (10.5% +/- 4.6%, P = 0.0007) compared with healthy volunteers (3.3% +/- 2.7%). Of all patients receiving MMF therapy, only patients with moderate to severe uveitis activity in the pre-MMF treatment group (n = 5; 15.5% +/- 5.0%, P = 0.004) had increased frequency of CD69-positive CD4 T cells compared with healthy volunteers. During MMF therapy, a significant reduction in frequency of CD69-positive CD4 T cells occurred in patients with prior moderate to severe uveitis activity (to 8.9% +/- 3.8%, P = 0.04). Levels of CD69-positive CD4 T cells in patients who had had inactive or mildly active disease (n = 5) before and during MMF therapy were comparable with levels in healthy volunteers. No significant changes in cytokine levels were found between the patient and control groups. A significant association between changes in frequency of CD69-positive CD4 T cells and changes in visual acuity (P = 0.008) and changes in vitreal haze (binocular indirect ophthalmoscopy score; P = 0.01) was observed in MMF-treated patients with prior moderate to severe uveitis activity. CONCLUSIONS: Reduction in uveitis activity during MMF therapy correlates with reduction in frequency of peripheral blood CD69-positive CD4 cells. The frequency of CD69-positive CD4 T cells is a measure of activity in posterior uveitis and may guide adequate immunosuppression.

Adult↗
PubMed2001

Expression of the chemokines MIP-1alpha, MCP-1, and RANTES in experimental autoimmune uveitis.

PURPOSE: To determine the location of the CC chemokines macrophage inflammatory protein (MIP)-1alpha, monocyte chemoattractant protein (MCP)-1, and regulated on activation of normal T-cell-expressed and secreted (RANTES) during disease progression in experimental autoimmune uveitis (EAU) and their relationship with the presence of the T helper cell (Th)1-type cytokine IFNgamma. METHODS: EAU was induced by immunization of Lewis rats with retinal extract. Consecutive cryostat sections were prepared from eyes at different stages of EAU, graded for severity of uveitis and stained by using antibodies to MCP-1, MIP-1alpha, and RANTES and to cell surface markers. Supernatants from superficial cervical lymph node cells were examined by ELISA for IFNgamma, IL-4, and IL-10. RESULTS: MIP-1alpha and IFNgamma were present most frequently and most extensively at peak disease but also were detectable in the choroid 8 days after immunization, before clinical disease onset. MCP-1 and RANTES were present at peak disease, but much less frequently. RANTES was occasionally found in the choroid before clinical disease. By days 19 to 21 after immunization, although infiltrating cells were present, there were only residual low levels of chemokine staining. MCP-1 and RANTES were detected on CD3-positive cells and on some ED1-positive cells, whereas MIP-1alpha was also associated with vessels and areas of exudate. Lymph node cells cultured from animals with peak disease had increased levels of IFNgamma and IL-10, but for IFNgamma this occurred only after stimulation in vitro with retinal extract. CONCLUSIONS: Although MCP-1 and RANTES were associated predominantly with cells infiltrating the retina, MIP-1alpha was also associated with resident cells. All three are likely to exacerbate EAU-MIP-1alpha, to the greatest degree.

Animals↗
PubMed2000

CXCR4 receptor expression on human retinal pigment epithelial cells from the blood-retina barrier leads to chemokine secretion and migration in response to stromal cell-derived factor 1 alpha.

Retinal pigment epithelial (RPE) cells form part of the blood-retina barrier and have recently been shown to produce various chemokines in response to proinflammatory cytokines. As the scope of chemokine action has been shown to extend beyond the regulation of leukocyte migration, we have investigated the expression of chemokine receptors on RPE cells to determine whether they could be a target for chemokine signaling. RT-PCR analysis indicated that the predominant receptor expressed on RPE cells was CXCR4. The level of CXCR4 mRNA expression, but not cell surface expression, increased on stimulation with IL-1beta or TNF-alpha. CXCR4 protein could be detected on the surface of 16% of the RPE cells using flow cytometry. Calcium mobilization in response to the CXCR4 ligand stromal cell-derived factor 1alpha (SDF-1alpha) indicated that the CXCR4 receptors were functional. Incubation with SDF-1alpha resulted in secretion of monocyte chemoattractant protein-1, IL-8, and growth-related oncogene alpha. RPE cells also migrated in response to SDF-1alpha. As SDF-1alpha expression by RPE cells was detected constitutively, we postulate that SDF-1-CXCR4 interactions may modulate the affects of chronic inflammation and subretinal neovascularization at the RPE site of the blood-retina barrier.

Adolescent↗
PubMed2000

Re-orientation and faster, directed migration of lens epithelial cells in a physiological electric field.

The vertebrate lens drives current through itself in a pattern which concentrates current efflux at the lens equator. Lens epithelial cells (LECs) move into this region where they change shape and differentiate into lens fibre cells. The mechanisms underpinning these cell behaviors are unclear. We have attempted to mimic, in isolation, the effects which such electrical signals have on LEC behaviors, by culturing LECs in a physiological DC electric field (EF) similar to that in lens. Primary human (PHLECs), primary bovine (PBLECs) and a transformed human cell line (THLECs) all changed shape to lie perpendicular to the EF, the same orientation which LECs adopt with respect to the equatorial EF as they differentiate into lens fibre cells. Exposure to an EF also significantly increased the migration rate of all three LEC types. All three LECs also showed directed cell migration although, curiously, different cell types moved in different directions. PBLECs and THLECs showed voltage-dependent, anode-directed migration, with a response threshold between 100-150 mV mm(-1)and 25-50 mV mm(-1), respectively. Small sheets of THLECs also migrated anodally. By contrast PHLECs migrated cathodally with a response threshold below 100 mV mm(-1). Reversing the polarity reversed the migration direction for each cell type. These observations raise three possibilities: (1) that small electric field may be one of the cues regulating lens epithelial cell behaviors in vivo; (2) that altering the in vivo electric field by lens replacement may contribute to the aberrant migration of epithelial cells in conditions such as posterior capsule opacification and (3) that applying electric fields may be one way of controlling aberrant lens epithelial cell behaviors.

Animals↗
PubMed2000

Control of chemokine production at the blood-retina barrier.

Chemokine production at the blood-retina barrier probably plays a critical role in determining the influx of tissue-damaging cells from the circulation into the retina during inflammation. The blood-retina barrier comprises the retinal microvascular endothelium and the retinal pigment epithelium. Chemokine expression and production by human retinal microvascular endothelial cells (REC) have never been reported previously, so we examined the in vitro expression and production of monocyte chemoattractant protein-1 (MCP-1), regulated on activation of normal T-cell expressed and secreted (RANTES), macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, interleukin (IL)-8, epithelial cell-derived neutrophil activating protein-78 (ENA-78) and growth related oncogene alpha (GROalpha) in these cells, both unstimulated and stimulated by cytokines likely to be present during the evolution of an inflammatory response. We compared this to expression and production of these chemokines in vitro in human retinal pigment epithelial cells (RPE). MCP-1 was expressed and produced constitutively by REC but all the chemokines were produced in greater amounts upon stimulation with the proinflammatory cytokines IL-1beta and tumour necrosis factor-alpha (TNF-alpha). MCP-1 and IL-8 were produced at much higher levels than the other chemokines tested. MIP-1alpha and MIP-1beta were present only at low levels, even after stimulation with IL-1beta and TNF-alpha. Cytokines with greater anti-inflammatory activity, such as IL-4, IL-10, IL-13, transforming growth factor-beta (TGF-beta) and IL-6, had little effect on chemokine production either by REC alone or after stimulation with IL-1beta and TNF-alpha. RPE, although a very different cell type, showed a similar pattern of expression and production of chemokines, indicating the site-specific nature of chemokine production. Chemokine production by REC and RPE is probably significant in selective leucocyte recruitment during the development of inflammation in the retina.

Blood-Retinal Barrier↗
PubMed2000

Automated detection of microaneurysms in digital red-free photographs: a diabetic retinopathy screening tool.

AIMS: To develop a technique to detect microaneurysms automatically in 50 degrees digital red-free fundus photographs and evaluate its performance as a tool for screening diabetic patients for retinopathy. METHODS: Candidate microaneurysms are extracted, after the image has been modified to remove variations in background intensity, by algorithms that enhance small round features. Each microaneurysm candidate is then classified according to its intensity and size by the application of a set of rules derived from a training set of 102 images. RESULTS: When 3,783 individual images were analysed and the results compared with the opinion of a clinical research fellow examining the same images, the program achieved a sensitivity of 81% and a specificity of 93% for the detection of images containing microaneurysms. Nine hundred and twenty-five sets of 4 images per patient were then analysed and the total number of microaneurysms detected compared with the overall patient retinopathy grade derived by the clinician examining the same images. In this context, intended to mimic a screening situation, the program achieved a sensitivity of 85% and a specificity of 76% for the detection of patients with (any) retinopathy (positive predictive value 0.71, negative predictive value 0.88). CONCLUSIONS: An automated technique was developed to detect retinopathy in digital red-free fundus images that can form part of a diabetic retinopathy screening programme. It is believed that it can perform a useful role in this context identifying images worthy of closer inspection or eliminating 50% or more of the screening population who have no retinopathy.

Algorithms↗