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Biomedical subjects

A Kijlstra

Publications and source records attributed to A Kijlstra.

At least 91 records · Page 5Linked to original sources
PubMed1995

Macular grid laser photocoagulation in uveitis.

AIMS/BACKGROUND: The aim of this study was to evaluate whether grid laser photocoagulation of the macula is beneficial in the treatment of cystoid macular oedema in patients with uveitis. METHODS: Six eyes of five patients with long standing cystoid macular oedema due to chronic uveitis were treated by grid laser photocoagulation of the macula. RESULTS: In the first weeks after treatment a temporary increase of oedema and paracentral scotomas were observed. At the long term follow up of more than 18 months in all patients, macular oedema had been reduced significantly or disappeared in all eyes treated. One eye had a significant increase in Snellen acuity, three eyes more or less stabilised, and two eyes deteriorated. CONCLUSION: The beneficial effect of laser treatment on visual acuity in patients with uveitis might be more favourable if performed at an earlier stage of the disease.

Adult↗
PubMed1995

Ivermectin detection in serum of onchocerciasis patients: relationship to adverse reactions.

Ivermectin treatment of onchocerciasis patients can be accompanied by adverse reactions. Not much is known concerning the pathogenesis of these reactions. Previous studies have demonstrated that the occurrence and extent of adverse reactions are related to infection intensity. However, some severely infected patients experience relatively few adverse effects. The aim of the present study was to investigate whether this seeming discrepancy could be due to diminished ivermectin absorption. Ivermectin concentrations one and two days after treatment were measured by high-performance liquid chromatography in sera of 71 skin snip-positive onchocerciasis patients (21 without reactions, 25 with mild reactions, 14 with moderate reactions, and 11 with severe reactions). The overall mean +/- SD ivermectin concentrations one and two days after a single oral dose (150 micrograms/kg) were 16.4 +/- 6.4 and 6.6 +/- 3.1 ng/ml, respectively. The overall mean +/- SD half-life was estimated to be 19.9 +/- 8.6 hr. The data presented did not show a relationship between ivermectin concentrations and the grade of adverse reactions.

Chromatography, High Pressure Liquid↗
PubMed1994

Detection of intraocular antibody production to herpesviruses in acute retinal necrosis syndrome.

In order to improve the determination of the causative agent in acute retinal necrosis syndrome, we evaluated the detection of intraocular antibody production to herpesviruses in 28 patients with this disease. Intraocular antibody production was determined by calculation of the Goldmann-Witmer coefficient whereby specific antibody titers in the inflamed eye and circulation are related to the total IgG content in ocular fluid and serum. Specific antibody titers to herpesviruses and Toxoplasma were determined by the indirect immunofluorescence technique. Thirty-five patients with ocular toxoplasmosis, cataract, or proliferative vitreoretinal disorders were tested as controls. By this technique, intraocular antibody production to varicella zoster virus or herpes simplex virus could be established in 16 (57%) of the patients with the typical clinical features of acute retinal necrosis, compared to none of the controls. Of the 33 affected eyes, 21 (64%) had a visual outcome of less than 20/200. We concluded that detection of intraocular antibody production to herpesviruses may be a useful diagnostic tool in establishing the causative agents in acute retinal necrosis.

Adult↗
PubMed1994

C-reactive protein and interleukin-6 are elevated in onchocerciasis patients after ivermectin treatment.

Ivermectin treatment of onchocerciasis can induce adverse reactions. Mechanisms underlying these reactions are poorly understood but may include activation of neutrophils. This study investigated the acute-phase response in onchocerciasis patients during 2 days after ivermectin treatment. The acute-phase protein C-reactive protein (CRP) and cytokines that mediate the acute-phase response (tumor necrosis factor-alpha [TNF alpha] and interleukin-6 [IL-6]) were measured in 144 skin snip-positive onchocerciasis patients and 12 skin snip-negative controls who received one dose of ivermectin (150 micrograms/kg). No elevated TNF alpha levels were found, but IL-6 and CRP were elevated in 25.7% and 50.7% of the patients, respectively, after ivermectin treatment. Most patients (89.2%) with raised IL-6 also had raised CRP. Such increases were not observed in controls and in patients were correlated with adverse reactions and microfilarial densities. These findings suggest a possible role of the acute-phase response in microfilarial destruction following ivermectin treatment.

Biomarkers↗
PubMed1994

Uveitis and anti-neutrophil cytoplasmic antibodies.

Serum samples of 485 uveitis patients were screened for the presence of anti-neutrophil cytoplasmic antibodies using a standardized immunofluorescence test (IIF) on neutrophil granulocytes. Seventeen of these sera contained cytoplasmic (C)-ANCA antibodies, while two of the sera contained perinuclear (P)-ANCA antibodies (both antinuclear antibody (ANA)-positive, one anti-myeloperoxidase (MPO)-positive). None of the C-ANCA-positive sera reacted with proteinase-3 in ELISA using a highly purified proteinase-3 preparation. Four C-ANCA and one P-ANCA-positive serum reacted with MPO. The majority of the sera did react with azurophilic granules in ELISA. The implication of these results is that in patients with uveitis a positive C-ANCA test is not diagnostic for Wegener's granulomatosis, but is most probably caused by the presence of autoantibodies against as yet unknown constituents of azurophilic granules.

Adolescent↗
PubMed1994

Polymorphism of tumour necrosis factor-alpha (TNF-alpha) at position -308 in relation to ankylosing spondylitis.

In addition to HLA-B27, other genetic factors are thought to be involved in the pathogenesis of ankylosing spondylitis (AS). Because of the localization, in the proximity of the HLA-B locus, and the biological activities of TNF-alpha, we investigated the association between AS and a single base polymorphism located at position -308 of the TNF-alpha gene. An allele-specific polymerase chain reaction was developed to monitor this polymorphism. The frequency of the TNF-alpha alleles was determined in 66 AS patients and 37 healthy controls. The TNF-alpha allele frequency was not significantly different between AS patients and controls.

Alleles↗
PubMed1994

Analysis of tear fluid proteins in insulin-dependent diabetes mellitus.

Secretory immunoglobulin A, lactoferrin, lysozyme and tear specific pre-albumin were analyzed in stimulated tear fluid of 25 diabetic patients without retinopathy and in 29 diabetic patients with (pre) proliferative retinopathy using high performance liquid chromatography. Results were compared to those obtained in 26 healthy controls to determine the effect of diabetes mellitus on the exocrine function of the main lacrimal gland. Sodium dodecyl sulfate polyacrylamide gel electrophoresis onto minigels was performed on 20 tear samples for verification of high performance liquid chromatography fractions recorded. The mean total protein values in tear fluid (Bradford assay) of diabetics without retinopathy, with retinopathy and healthy controls did not differ significantly (mean in mg/ml +/- SD: 6.4 +/- 2.2, 5.9 +/- 2.0 and 5.7 +/- 1.7, respectively; Mann-Whitney; p > 0.02). High performance liquid chromatography showed an increased secretory immunoglobulin A and decreased peak 5 OD280 (+56% and -38%, respectively; p < 0.02) in patients without retinopathy, whereas in patients with retinopathy lysozyme was increased (+27%; p < 0.01) and tear specific pre-albumin and peak 5 OD280 decreased (-24% and -42%, respectively; p < 0.04), when compared to healthy controls. These inconsistent differences do not uniformly suggest an exocrine dysfunction of the main lacrimal gland in diabetic patients.

Adolescent↗
PubMed1994

Blindness from uveitis in a hospital population in Sierra Leone.

A retrospective study was conducted to assess the causes of blindness and visual impairment in patients who visited an eye hospital in Sierra Leone, West Africa, in 1989 and 1992. These data were compared with figures from 1981. Throughout the years, senile cataract was the major cause of blindness, followed by uveitis (including onchocerciasis). Uveitis remained the second most important cause of blindness in this population, despite the significant decrease in blindness from onchocerciasis (from 30% in 1981 to 15% in 1992). An increasing number of patients with uveitis from non-onchocercal origin was observed: almost 10% of the blindness found in 1992 was due to uveitis of non-onchocercal origin. A reduction in visual handicap in patients with non-onchocercal uveitis could be achieved if local hospitals could obtain more accurate diagnoses in these patients.

Age Distribution↗
PubMed1994

Low mature TGF-beta 2 levels in aqueous humor during uveitis.

PURPOSE: To investigate whether transforming growth factor-beta 2 (TGF-beta 2), a strong immunosuppressive factor normally present in aqueous humor, is involved in the inflammatory process of clinical uveitis. METHODS: Mature TGF-beta 2 levels were determined in aqueous humor samples of 9 patients with Fuchs' heterochromic cyclitis, aqueous humor samples of 21 patients with other uveitis entities, and vitreous fluid samples of 19 patients with uveitis by using a commercially available sandwich ELISA: Total TGF-beta 2 levels in ocular fluids were measured after heat activation. Aqueous humor samples from patients with cataract and glaucoma and vitreous fluid samples from eye bank eyes were tested as controls. Albumin levels, determined by radial immunodiffusion, were used as a measure of the disruption of the blood aqueous barrier. RESULTS: Significantly lower mature TGF-beta 2 levels were detected in aqueous humor samples of patients with uveitis, compared to the two control groups without intraocular inflammation. Samples of patients with uveitis without detectable mature TGF-beta 2 did contain latent TGF-beta 2 levels (504 to 6024 pg/ml). In aqueous humor, there was a significant negative correlation between mature TGF-beta 2 and albumin levels. No mature TGF-beta could be detected in vitreous fluid. Total TGF-beta 2 levels in vitreous fluid were significantly lower in samples from patients with uveitis than in samples from eye bank eyes. CONCLUSION: These results indicate that the mature TGF-beta 2 levels in aqueous humor and the total TGF-beta 2 levels in vitreous fluid are reduced during ocular inflammation. In aqueous humor, this might be caused by binding of mature TGF-beta to serum proteins, for instance, alpha 2-macroglobulin, or by a disturbance in the activation process of latent TGF-beta 2.

Aqueous Humor↗
PubMed1994

Expression of multiple cytokines and IL-1RA in the uvea and retina during endotoxin-induced uveitis in the rat.

PURPOSE: Ample evidence is available demonstrating that cytokines play a pivotal role in the pathogenesis of uveitis. Because little is known concerning the site of cytokine synthesis in the eye, cytokine mRNA expression was analyzed in the uvea, retina, and cornea during endotoxin-induced uveitis (EIU) in the rat. METHODS: RNA was isolated from the iris, ciliary body, choroid-sclera, retina, and cornea at different points in time after foot-pad injection of 200 micrograms lipopolysaccharide (LPS) in Lewis rats. Reverse-transcription polymerase chain reaction analysis was used to determine tumor necrosis factor alpha (TNF-alpha), interleukin 1 beta (IL-1 beta), IL-6, IL-10, interferon gamma (IFN-gamma), monocyte chemotactic protein 1 (MCP-1), macrophage inflammatory protein 2 (MIP-2), and IL-1 receptor antagonist (IL-1RA) mRNA expression. RESULTS: Maximal mRNA expression of all cytokines examined already was observed in the uvea 4 hours after systemic LPS injection, before the onset of clinical uveitis. Elevated expression of TNF-alpha, IL-1 beta, IL-6, IFN-gamma, MCP-1, and MIP-2 was also observed concomitant with maximal uveitis, at 22 to 24 hours. Except for IL-10 and IFN-gamma, all cytokines investigated were induced in the retina, with maximal expression at 22 to 24 hours. Expression of IL-1RA was detected in the uvea and retina at 4 hours and remained elevated up to 48 hours, when the clinical uveitis started to decline. LPS did not induce cytokine expression in the cornea. Strikingly, a considerable expression of IL-1RA was found in normal corneas, suggesting an inherent control mechanism for IL-1-mediated responses. CONCLUSIONS: Systemic LPS injection induces elevated mRNA expression of multiple cytokines and IL-1RA in the uvea and retina during various stages of EIU. This suggests that these mediators may contribute to the development and recovery of this intraocular inflammation.

Animals↗
PubMed1994

Kinetics of intraocular tumor necrosis factor and interleukin-6 in endotoxin-induced uveitis in the rat.

PURPOSE: To determine the kinetics of tumor necrosis factor (TNF) and interleukin-6 (IL-6) in serum and aqueous humor of rats with different susceptibilities to endotoxin-induced uveitis (EIU), after footpad injection of lipopolysaccharide (LPS). METHODS: Samples were collected from EIU-susceptible Lewis rats and EIU-resistant Brown Norway (BN) rats for up to 72 hours after LPS injection. Specific bioassays were used to measure TNF and IL-6 activity. Northern blot analysis was used to assess intraocular IL-6 mRNA expression. RESULTS: High levels of TNF and IL-6 were detected in serum of both rat strains early after LPS injection. A second rise in serum TNF was observed at 18 to 20 hours in Lewis rats only. In aqueous humor of Lewis rats, high levels of TNF and IL-6 were observed early after LPS injection (2 to 8 hours) and concomitant with maximal uveitis (18 to 24 hours). Low levels of TNF and IL-6 were found in aqueous humor of BN rats. Ocular IL-6 mRNA was detected at the same time as IL-6 activity was measured in aqueous humor. CONCLUSIONS: The results of this study indicate that both TNF and IL-6 may play a role in the pathogenesis of EIU. The early release of TNF in aqueous humor during EIU suggests that this cytokine may serve as an initial mediator of intraocular inflammation. Furthermore, Northern blot analysis indicates that IL-6 is produced locally during EIU.

Animals↗
PubMed1994

Morphology and function of the corneal endothelium after long-term contact lens wear.

PURPOSE: To examine whether corneal hydration control is impaired in corneas with endothelial morphologic changes (increased variation in cell size and cell angularity) due to long-term low gas-permeable contact lens wear. METHODS: Twenty-one long-term wearers of low gas-permeable contact lenses (mean age, 41 years +/- 8 SD) and 18 age-matched controls (mean age, 42 years +/- 8 SD) were studied. To assess endothelial morphology, endothelial photographs were taken, enlarged 400X, scanned into a computer, and evaluated. Hydration control was assessed by a corneal stress test. Corneal swelling was induced by applying low gas-permeable soft contact lenses for 2 hours during eye closure. After the lenses were removed, the rate of deswelling was determined using optic pachometry. RESULTS: Morphologic analysis of the endothelial photographs showed a significant increase of polymegethism (P < 0.01) and pleomorphism (P < 0.01) in the group wearing contact lenses compared with the control group. The percentage of recovery of corneal thickness per hour (PRPH) from induced swelling proved to be significantly lower (P = 0.03) and the induced swelling proved to be significantly lower (P < 0.01) in the group wearing contact lenses than in the control group. Multiple regression analysis showed that the PRPH decreased as the morphologic alterations increased. However, this trend appeared not to be significant at the 5% level. A significant relationship was found between morphologic parameters and induced swelling, indicating that induced swelling decreased as the morphologic alterations increased. CONCLUSION: The results of this study indicate that increased endothelial polymegethism and pleomorphism may be accompanied by a decreased corneal hydration control in people who wear contact lenses.

Adult↗
PubMed1994

Human corneal extract enhances serum complement activity.

PURPOSE: The concomitant presence of complement-activation products in the cornea during inflammation is well described. The present study was undertaken to analyze the complement activity of normal human corneal tissue and to assess the presence of complement-modulating activities. METHODS: Human corneal tissue was extracted in veronal-buffered saline. The overall complement (C) activity of the human corneal extract (HCE) and the effect of HCE on serum C-activity were investigated using a hemolytic assay. Anion-exchange chromatography and gel filtration were applied for biochemical analysis of HCE. Monoclonal anti-human C3 was used to detect corneal C3 and to remove C3 from HCE by immunoadsorption. RESULTS: It was found that C-activity of HCE was less than 200 U/g tissue. Experiments to test whether HCE exhibited inhibitory activity led to an unexpected result: When added to human serum dilutions, HCE caused a significant, dose-dependent increase of C-activity. Pretreatment of HCE at 56 degrees C abolished the effect. Analysis of HCE by anion-exchange chromatography revealed two C-enhancing peaks. One peak was identified as C3 whereas the identity of the other protein peak remained unknown. CONCLUSIONS: Results indicate that the human cornea contains an as yet unidentified heat sensitive factor(s) able to enhance complement activity of serum. It is postulated that this factor(s) may play an important role in corneal physiology and pathology.

Chromatography, Gel↗
PubMed1993

Long-term effects of ceftriaxone treatment on intraocular Lyme borreliosis.

Twelve patients with intraocular Lyme borreliosis suffering from vitreitis were treated with ceftriaxone intravenously. Eight patients had definitive Lyme borreliosis, and tentative diagnosis was made in four patients. After treatment with ceftriaxone, all 12 patients were followed up for more than one year. Vitreitis diminished in all patients and visual acuity improved in six patients. The best results were achieved in patients with definitive Lyme borreliosis.

Adult↗
PubMed1993

Treatment and prognosis of secondary glaucoma in Fuchs' heterochromic iridocyclitis.

After reviewing the records of 111 patients with Fuchs' heterochromic iridocyclitis, we studied the therapy and prognosis of secondary glaucoma in 30 of these 111 patients (27%) who had glaucoma or could be considered glaucoma suspects. Maximal medical therapy was unsuccessful in 22 of the 30 patients (73%). Surgical intervention (mostly trabeculectomies, half with 5-fluorouracil) successfully controlled intraocular pressure (< or = 21 mm Hg with or without medication) in 13 of the 18 operated-on patients (72%) after a mean follow-up of 26 months. All successfully operated-on patients retained a visual acuity of 20/80 or better. We had favorable results, possibly because of modern surgical techniques (use of 5-fluorouracil, sodium hyaluronate) or earlier surgical intervention, or both.

Adult↗