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Biomedical subjects

A Kijlstra

Publications and source records attributed to A Kijlstra.

At least 19 recordsLinked to original sources
PubMed1992

Immune deposits in iris biopsy specimens from patients with Fuchs' heterochromic iridocyclitis.

To investigate whether Fuchs' heterochromic iridocyclitis may be an immune complex vasculitis, we used an immunofluorescence technique to detect immunoglobulins and complement in iris biopsy specimens from nine patients with Fuchs' heterochromic iridocyclitis, 12 patients with other types of uveitis, and nine patients with glaucoma but without uveitis. No specific immune deposits were observed in the irises of the patients with Fuchs' heterochromic iridocyclitis. Immunoglobulin G, IgA, IgM, and complement were detected in patients with Fuchs' heterochromic iridocyclitis and patients with uveitis, and these results differed significantly (P less than .05) from the group without uveitis. The immune deposits were found only in the iris vessel walls. No light-microscopic evidence of an inflammatory vascular process could be detected. Further studies are necessary to investigate whether the immune reactants originate from the circulation or result from local formation.

Adult↗
PubMed1992

Fuchs' heterochromic iridocyclitis is not associated with ocular toxoplasmosis.

To analyze the association between Fuchs' heterochromic iridocyclitis (FHI) and toxoplasmosis, we performed ocular examinations and used various specific laboratory tests to establish a role for Toxoplasma gondii in the pathogenesis of FHI. Results were compared with those for other types of uveitis and healthy controls. Of the 88 patients with FHI, nine (10.2%) had toxoplasmosislike scars, but an association could not be proved by the indirect immunofluorescence antibody test or enzyme-linked immunosorbent assay, or by a test for cellular immunity to Toxoplasma antigen. Analysis of aqueous humor samples for Toxoplasma antibodies in patients with FHI also yielded negative results. On the basis of the negative results of these laboratory tests, we concluded that FHI is not associated with ocular toxoplasmosis.

Adolescent↗
PubMed1992

Analysis of the electroretinogram in toxoplasma retinochorioiditis.

The decision to use therapy in toxoplasma retinochorioiditis depends on the location of the active lesion and the presence of vitreous activity. In eyes with dense vitreous clouding it can be difficult to see whether the macular region is involved or not. In theory the localisation of a lesion can be estimated on the basis of the flash ERG. The standard flash electroretinogram was recorded in 23 patients with inactive toxoplasma retinochorioiditis lesions in the retina. In 17 cases a lesion was present within the central 12 degrees of the visual field, 8 of these had a reduced photopic ERG. In 15 patients lesions were found outside the central 12 degrees, in 8 of whom the scotopic ERG was reduced. We conclude that the ERG can be of use in indicating the scar location in patients with dense vitreous clouding.

Adolescent↗
PubMed1992

Anti-retinal S-antigen antibodies in human sera: a comparison of reactivity in ELISA with human or bovine S-antigen.

Various studies have demonstrated anti-retinal S-antigen (S-ag) antibodies in uveitis sera in assays using bovine S-ag. Because of its molecular similarity and cross-reactivity with human S-ag, reactions with bovine S-ag have been considered a reliable indication of anti-S-ag autoimmunity. To test this assumption, the cross-reactivity of purified human and bovine S-ags was quantitated by ELISA titration of various anti-human and anti-bovine S-ag immune reagents raised in mice, rats and rabbits. Anti-human S-ag reagents appeared to be largely cross-reactive with bovine S-ag, whereas anti-bovine S-ag reagents were 6-10 times less reactive with the cross-reacting human S-ag than with bovine S-ag, thus showing a predominant role of species-specific epitopes on bovine S-ag. Furthermore, a large number of human control and uveitis sera was tested in ELISA with both human S-ag- and bovine S-ag-coated microwells. Both the numbers of positive sera and the levels of anti-S-ag antibodies in the two tests significantly correlated, but many exceptions were found, and the predictive value of reactions with bovine S-ag for the presence and levels of anti-S-ag autoantibodies was low. For individual human sera, assessment of anti-S-ag autoantibodies requires the use of human S-ag in immunoassays.

Animals↗
PubMed1992

Analysis of aqueous humour in uveitis by high performance liquid chromatography and sodium dodecyl sulphate-polyacrylamide gel electrophoresis.

Aqueous humour from patients with Fuchs' heterochromic cyclitis (FHC) and other types of uveitis was analysed by high performance liquid chromatography (HPLC) and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Using HPLC, the number of peaks and their respective elution times were similar for the FHC, uveitis and control groups. SDS-PAGE and silver staining showed immunoglobulin G migrating as two to four distinct bands in all non-reduced samples. In the reduced state, 1-5 unidentified low MW bands (10-19 kD) were seen. Two bands at 19 and 10 kD appeared to be specific for the uveitis group, and a band at 11 kD was present in 76% of uveitis and 19% of FHC patients. None of these three bands were detected in any of the control group. As yet the identity of these low MW proteins and their possible significance in the pathogenesis of intraocular inflammation are unknown.

Adult↗
PubMed1992

Isoelectric focusing pattern of human corneal aldehyde dehydrogenase.

The major soluble protein in the bovine cornea (BCP 54) has recently been identified as a class 3 aldehyde dehydrogenase. An enzymatic and even a possible structural role of this protein in the mammalian cornea has been proposed. Earlier we showed that the human cornea contains the same enzyme but with a different substrate specificity, compared to the bovine. Moreover, the enzymatic activity was harbored in the dimeric 88-kD species. Genetic variants have been found for several mammalian ocular aldehyde dehydrogenases. In this study we investigated whether such variants were also present in the human cornea by using a zymography technique for aldehyde dehydrogenase activity and immunoblotting with rabbit anti-BCP 54 and lectin staining after isoelectric focusing (IEF) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. We investigated 50 individual human corneal epithelial extracts and found one common IEF variant (n = 47) and two "rare" IEF variants in three individuals. Analysis of these patterns indicates that the observed IEF profiles may be caused by posttranslational events.

Adolescent↗
PubMed1992

Fluorophotometric assessment of tear turnover under rigid contact lenses.

To examine the effect of rigid contact lens design on tear turnover the left and right eyes of 25 healthy volunteers were randomly fitted with either a spherical or an aspherical contact lens. Tear turnover is defined as the percentage of decrease of fluorescein concentration in the tear film per minute as a result of tear flow after instillation of fluorescein and can be determined with a fluorophotometer. A drop of fluorescein (1 microliter, 2%) was instilled in each contact lens-wearing eye, whereafter the decrease of the fluorescein was measured for about 30 min. The test was repeated without contact lenses. No statistically significant difference was found between the tear turnover in the spherical, the aspherical, and the non-contact lens-wearing eyes (mean values +/- SD: 15.2 +/- 4.9, 15.6 +/- 5.9, and 16.9 +/- 6.8%/min, p > 0.20).

Adult↗
PubMed1992

Induction of autoantibodies to rat corneal protein 54.

Many studies have described the presence of circulating antibodies against corneal components in patients with corneal disease or uveitis, and in patients with skin or systemic disease with or without ocular involvement. The role of such antibodies in the underlying immunopathological process remains obscure. Here we describe the induction of autoantibodies against the rat cornea. Our attempts to induce corneal autoantibodies by various forms of keratitis and corneal trauma failed. However, circulating corneal autoantibodies could be detected by Western blotting after immunization of BN rats and Lewis rats with bovine corneal protein 54 (BCP 54). Rats immunized with rat corneal extracts (RaCE) or human serum albumin (HSA) as (auto) antigen did not develop corneal autoantibodies. During the study period (greater than 4 months), it was observed that the presence of circulating corneal autoantibodies did not elicit corneal inflammation. Severe keratitis did develop when BCP 54-immunized rats were challenged intracorneally with BCP 54, but the clinical signs were not significantly different from HSA-immunized rats after an intracorneal HSA challenge. Injection of corneal autoantibodies into the corneal stroma did not provoke keratitis. To the best of our knowledge this is the first study demonstrating corneal autoantibodies in rats without actual manipulation of the eye. This model may provide further insights in the role and significance of corneal autoantibodies in disease.

Aldehyde Dehydrogenase↗
PubMed1992

Uveitis and systemic disease.

A prospective study was conducted of 865 patients with uveitis to determine the frequency of associated systemic diseases and to assess the value of limited laboratory screening of these patients. All patients underwent a standard diagnostic protocol followed--when indicated--by special tests and procedures performed in order of likelihood ('tailored approach'). For 628 patients (73%) a specific diagnosis was established based on history, ophthalmologic examination, and laboratory and radiographic studies. A definite association with systemic disease was determined for 220 patients (26%). A relationship with a subclinical systemic disorder could be presumed in 201 cases (23%) and a well-established clinical uveitis entity without a recognisable systemic disorder was present in 207 cases (24%). For 237 patients (27%) a diagnosis could not be determined. The most frequently observed systemic diseases were sarcoidosis (7%) and HLA-B27-associated seronegative spondylarthropathies (6%). Presumed or definite toxoplasmosis was encountered in 10% of cases. HLA-B27-associated acute anterior uveitis was the most common clinical entity (17%). In the majority of cases the presence of a systemic disease was not suspected prior to eye involvement and was only recognised after the subsequent diagnostic procedures.

Adolescent↗
PubMed1992

Analysis of IL-6 levels in human vitreous fluid obtained from uveitis patients, patients with proliferative intraocular disorders and eye bank eyes.

Several studies suggest a role for IL-6 in the pathogenesis of uveitis. Earlier we have shown that aqueous humour obtained from patients with uveitis contained raised levels of IL-6. In the study described here we investigated the IL-6 levels in vitreous fluid samples obtained from 75 uveitis patients with different uveitis entities. Vitreous samples from 14 patients with proliferative intraocular disorders (PID) and 29 eye bank eyes were used as controls. All the samples were tested in the IL-6 B9 bioassay as well as in a sensitive ELISA for IL-6. Raised IL-6 levels were detected in the vitreous fluid of uveitis patients as well as patients with PID, implicating IL-6 as a common inflammatory mediator. The highest mean level of IL-6 was found in the vitreous fluid of patients with acute retinal necrosis. The mean IL-6 levels measured by the ELISA were higher compared to the levels measured by the B9 bioassay. This may be caused by the presence of B9 bioassay inhibitory factors in the vitreous fluid of these patients.

Biological Assay↗
PubMed1992

Anticardiolipin antibodies in uveitis.

Anticardiolipin antibodies (ACA) have been described in association with thrombosis and several vascular diseases and may be involved in retinal vasculitis. To investigate this question we tested sera from 86 patients with posterior uveitis and 100 healthy controls for the presence of anticardiolipin antibodies. The antibody was present in 15 patients: in 7 of the patients with acute retinal necrosis (n = 24), in 4 with idiopathic retinal vasculitis (n = 10), 3 with syphilis (n = 6) and in one SLE patient with retinal vasculitis. Ten patients had IgA-type anticardiolipin antibodies, 6 had IgM-type and 4 had IgG-type anticardiolipin antibodies. Anticardiolipin antibodies could not be detected in sera from uveitis patients with Behçet's disease (n = 10), sarcoid (n = 9), toxoplasmosis (n = 7), multiple sclerosis (n = 3) or Birdshot chorioretinopathy (n = 10). Ten of the healthy controls had cardiolipin antibodies of the IgM class. The exact role of these auto-antibodies in the pathogenesis of retinal vasculitis remains to be resolved.

Antibodies, Anticardiolipin↗
PubMed1992

Transient decrease of secretory IgA in tears during rigid gas permeable contact lens wear.

Decreased humoral defense mechanisms may be involved in the occurrence of keratic ulcerations after contact lens wear. To investigate the effect of contact lens wear on tear protein composition a prospective study was performed whereby tears were collected with Schirmer papers from 42 healthy individuals, before and at varying times after contact lens wear. Tear proteins were quantitated using HPLC analysis. Analysis of tear fluid by HPLC is a rapid and simple technique to detect the major tear proteins. Four separate peaks containing respectively IgA, lactoferrin, TSPA and lysozyme can easily be identified. The results show that the mean relative level of secretory IgA in the collected tear samples decreased significantly after the first months of contact lens wear but was not significantly altered after one year. The decrease in IgA was accompanied by a significant increase in the relative amount of lysozyme, whereas the levels of lactoferrin and TSPA remained the same. Certain individuals showed a marked decrease in their tear secretory IgA levels after wearing the lenses for more than one year. Future studies will clarify whether such individuals are at higher risk to develop corneal complications.

Adolescent↗
PubMed1992

Molecular weight forms of corneal aldehyde dehydrogenase.

Aldehyde dehydrogenase has recently been shown to be one of the major soluble proteins in the mammalian cornea. The enzyme has a subunit molecular weight of 54 kd and gel filtration experiments indicate that a dimer molecule is the enzymatically active species. The purpose of the studies described here was to investigate whether oligomeric forms of this enzyme could also be detected using the much faster SDS-PAGE mini-gel electrophoresis technique combined with immunoblotting and "in gel" enzyme detection. Low temperature treatment of samples prior to electrophoresis revealed that both human and bovine corneal ALDH are mainly present as a 54 kd and as a dimer molecule with an apparent molecular weight of 88 kd. Bovine corneal ALDH also contained larger oligomers with a molecular weight of 110, 154 and 210 kd respectively. The classical 3 minutes boiling procedure prior to SDS-PAGE dissociated the oligomers into the 54 kd subunit. Zymography experiments showed that enzyme activity was only present in the 88 kd form of corneal ALDH. Pretreatment of corneal ALDH at various temperatures showed that the temperature induced shift of the 88 kd species to the 54 kd subunit paralleled the decrease in enzymatic activity. The fact that reduction of samples with DTT did not dissociate the 88 kd form suggests that disulfide bridge formation is not involved in the oligomerisation of corneal ALDH.

Aldehyde Dehydrogenase↗
PubMed1992

Cytokines and uveitis, a review.

Although the exact pathogenic mechanisms underlying uveitis are unknown, cytokines appear to be involved in this inflammatory disorder. This review describes the studies in which the uveitogenic properties of several cytokines, including tumor necrosis factor (TNF), interleukin 1 (IL-1), IL-6, IL-8 and interferon gamma (IFN-gamma), were investigated and the reports on intraocular expression of cytokines, such as TNF, IL-2, IL-6 and IFN-gamma, during uveitis. The exact contribution of these mediators to uveitis remains to be determined. This may provide new clues in the treatment of uveitis.

Animals↗
PubMed1992

Polymorphism of the tumor necrosis factor region in relation to disease: an overview.

HLA antigens have been shown to be associated with several immunoinflammatory diseases. The mechanisms by which these antigens confer susceptibility to disease continue to be of major interest. Rapid progress has been made in the elucidation of the structure and function of class I and II MHC molecules, and several genes located within the HLA complex have been identified which are potentially involved in immunologic processes. Because of the HLA localization of the TNF-alpha and -beta genes and the biologic activities of the gene products, recent investigation has focused on a possible role of polymorphic TNF genes in the pathogenesis of HLA-associated diseases. Allelic variations have only been detected in the TNF-beta gene. No evidence has been found so far that a particular TNF-beta allele contributes significantly in the susceptibility to the diseases studied. Although it has been postulated that the TNF beta*2 allele contributes to susceptibility to IDDM in HLA-DR3, 4 heterozygous individuals, a larger group of HLA-typed patients and controls is needed to provide more conclusive evidence for this hypothesis. The increasing number of genes of unknown function encoded by the class III region leaves the possibility that the observed HLA associations in some diseases may be related to the presence of these genes. In AS, the lack of association with the TNF-beta alleles furthermore supports the function of the HLA-B27 molecule in the disease and underlines the improbability that HLA-B27 is merely a marker for a closely linked susceptibility gene.

Cytokines↗
PubMed1992

Endotoxin-induced uveitis in the rat. The significance of intraocular interleukin-6.

The potential role of interleukin-6 (IL-6) was studied as an inflammatory mediator of endotoxin (or lipopolysaccharide [LPS])-induced uveitis (EIU) in the rat. In young Lewis rats, levels of intraocular IL-6, but not serum IL-6, correlated with the severity of uveitis and with aqueous humor protein levels in response to foot pad injections of LPS (P less than 0.001). Adult Lewis rats did not develop uveitis and had no intraocular IL-6, although IL-6 was released systemically. Resistance to EIU and absence of IL-6 levels in the aqueous humor, despite the ability to release serum IL-6, also were observed in brown Norway rats, irrespective of age and weight. Intravitreal injection of as little as 1 ng of human recombinant IL-6 induced uveitis in young Lewis rats. In adult Lewis rats, and in young animals made tolerant to LPS, intravitreal IL-6 still caused substantial leakage of plasma proteins into the anterior chamber but no influx of inflammatory cells. As early as 2 hr after intravitreal injection of IL-6, immunohistochemical analysis showed invasion of the iris, corneal stroma, and anterior chamber by polymorphonuclear leukocytes (PMN) and expression of major histocompatibility complex (MHC) class II antigen in the retina by large cells that were macrophage-marker ED2 negative. This was followed by massive PMN infiltration of the retinal layers and vitreous. The MHC class II antigen expression of ciliary and iris epithelium occurred at a later stage (greater than 8 hr).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗