Biomedical subjects

A Kijlstra

Publications and source records attributed to A Kijlstra.

At least 145 records · Page 8Linked to original sources

PubMed1991

The fate of antigen-antibody complexes in the rabbit cornea.

The mechanisms involved in the clearance of immune deposits in tissues are not yet clear. The cornea was chosen as a model to examine this question due to its avascularity and transparency. Bovine serum albumin (BSA) and rabbit anti BSA serum were injected at opposite sites into the corneal stroma of unsensitized rabbits. Within a day, a sharp opaque line was seen macroscopically between the two injection sites. Sections of the corneas were examined by light microscopy and electron microscopy; furthermore, immunohistochemical techniques were used. With the light microscope, a precipitation line was seen in the corneal stroma, which was identified as an antigen-antibody complex by immunofluorescence techniques. In the same area infiltrating polymorphonuclear cells and swollen keratocytes were observed. In the ultrathin sections precipitates were seen lying between the collagen fibrils without affecting the structure of the collagen. The swollen keratocytes had an activated rough endoplasmic reticulum. In certain cases the precipitates appeared to be intracellular, both in the polymorphonuclear cells, as well as in the keratocytes. These findings suggest that stromal keratocytes may play an important role in the degradation of corneal immune deposits.

Animals↗

PubMed1991

Detection of aldehyde dehydrogenase activity in human corneal extracts.

The major soluble protein in bovine corneal epithelial extracts is a 54 kD protein (BCP 54) which has recently been identified as the corneal aldehyde dehydrogenase. Although ALDH activity has been reported in human corneal extracts it was not yet clear whether this was identical with the 54 kD protein described in bovine corneas. To investigate this question, we studied human corneal extracts for the presence of ALDH using enzyme analysis, SDS-PAGE, native electrophoresis, isoelectric focusing and immunoblotting techniques. The corneal epithelium was the most active layer (8.46 +/- 1.9 IU/mg protein) followed by the stroma (2.83 +/- 0.56 IU/mg protein) and endothelium (0.06-3.6 IU/mg protein). When comparing substrate specificity between human and bovine corneal ALDH, using NADP as coenzyme, it was shown that the human enzyme preferred benzaldehyde whereas the bovine enzyme revealed the strongest enzymatic activity with hexanal. Human corneal ALDH was partly inhibited by disulfiram. Bovine and human cornea ALDH lost their enzymatic activity after heating at temperatures above 56 degrees C. Both human and bovine corneal extracts contained a prominent 54 kD protein which reacted with a rabbit anti BCP 54 antibody. Isoelectric focusing followed by enzyme staining in the gel revealed 5 human corneal isozyme species and 4 in bovine corneal extracts, migrating at a pH between 6.5 and 7.0. All isozymes could also be detected after immunoblotting with a rabbit anti BCP 54 antibody.

Aldehyde Dehydrogenase↗

PubMed1991

Identification of lectin binding proteins in human tears.

The identity of glycoproteins in stimulated normal human tears was investigated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of tears onto minigels, blotting, and subsequent incubation with different biotinylated lectins (concanavalin A [Con A], peanut agglutinin [PNA], glycine max agglutinin [SBA], Phaseolus vulgaris agglutinin, wheat germ agglutinin [WGA, native form], Artocarpus integrifolia agglutinin [Jacalin], and Pisum sativum agglutinin). Control proteins included purified secretory immunoglobulin A (sIgA) from human colostrum, human milk lactoferrin, and chicken-egg lysozyme. All samples were prepared in a denaturing (SDS) buffer under nonreducing and reducing conditions. The sIgA in tears and IgA (alpha) heavy chain fragments (reduced sample) were identified with most of the lectins tested. A particular high molecular weight (greater than 200 kD) protein fraction in tears that just entered the separation gel on SDS-PAGE was detected with WGA and Jacalin. This fraction stain poorly with silver. Tear lactoferrin was identified with all lectins used, although binding was low with SBA. Purified milk lactoferrin showed a poor reaction with Jacalin, but a protein in tears of similar mobility bound this lectin (nonreduced samples). Under both nonreducing and reducing conditions, tear-specific prealbumin in tears did not bind any of the lectins tested. Tear lysozyme only reacted with lectin after reduction. The techniques described may provide additional valuable information in addition to commonly used methods for tear protein analysis and further knowledge concerning the role of glycoproteins on the ocular surface.

Electrophoresis, Polyacrylamide Gel↗

PubMed1991

Analysis of corneal inflammation following the injection of heterologous serum into the rat cornea.

The immunopathologic response following the injection of various antigens into the rat cornea was evaluated. This reaction, known as Wessely's phenomenon, was believed to be primarily triggered by antibodies and complement activation. The keratitis model was originally described in rabbits, using heterologous serum or purified proteins. In rats only, heterologous serum induced corneal inflammation with the characteristics of Wessely's phenomenon, (ie, a quiescent period of several days between antigen injection and onset of clinical signs and corneal opacification). Using rats allowed us to characterize the cellular infiltrate with immunohistochemical methods. Marked infiltration of the cornea by macrophages was observed, as was infiltration by polymorphonuclear cells, although to a lesser extent. Furthermore, T lymphocytes of the helper phenotype were demonstrated. Antibodies to complement activation product C3c showed faint staining, whereas B lymphocytes and plasma cells were absent. In addition, inflammatory cells and ocular tissues, particularly the limbal and peripheral corneal epithelium, were found to express major histocompatibility complex class II antigens during the inflammatory response. After the inflammation had subsided, macrophages and T lymphocytes remained in the corneal stroma (at least until day 30). These findings suggest that antigen-induced keratitis in rats might be mediated, at least partially, by T helper lymphocytes.

Animals↗

PubMed1991

The lifetime cumulative incidence of acute anterior uveitis in a normal population and its relation to ankylosing spondylitis and histocompatibility antigen HLA-B27.

The lifetime cumulative incidence of acute anterior uveitis (AAU) was determined in a sample of a large population (n = 10,500). Nine hundred seventeen subjects, who answered the question "Have you ever had a red eye" in the affirmative in 1977, were asked to participate in a follow-up study 10 years later. From the 917 respondents, 539 were studied completely. A questionnaire was used to collect historic data, and confirmation of these data was obtained from the treating ophthalmologists and physicians. From these data, subjects were selected for an ophthalmologic examination. The respondents also underwent a rheumatologic examination. The results revealed that the lifetime cumulative incidence of definite AAU is approximately 0.2% in the general population and 1% in the histocompatibility antigen HLA-B27-positive population. In one third of the definite AAU patients, the cause of the disease was known. The lifetime cumulative incidence of definite AAU of unknown cause was 0.15% in the general population. When possible and probable AAU are included, the lifetime cumulative incidence of AAU in the general population is about 0.4%. The observed frequency of the concurrence of AAU and ankylosing spondylitis (AS) was 0.4% in the HLA-B27-positive population and 0.02% in the HLA-B27-negative population. Comparison with the expected frequency of the concurrence of AAU and AS revealed that AAU and AS probably are related diseases irrespective of the association of both diseases with HLA-B27.

Acute Disease↗

PubMed1991

Analysis of interleukin-6 in endotoxin-induced uveitis.

The mechanisms underlying the induction of intraocular inflammation in the rat model of endotoxin-induced uveitis (EIU) and the subsequent development of tolerance after repeated endotoxin injections are poorly understood. Interleukin-6 (IL-6) was measured in the aqueous humor and serum of Lewis rats after single and repeated injections of endotoxin into the footpad. After a single injection, a rise in serum and aqueous-humor levels of IL-6 was seen after 2 and 16 hr, respectively. The highest aqueous-humor level of IL-6 was seen 20 hr postinjection and was tenfold that seen in the serum sample taken at the same time, suggesting intraocular synthesis of this cytokine. Four hours later the most active uveitis and the highest total aqueous-humor protein level were observed. Repeated injection of endotoxin still resulted in a moderate but significant systemic release of IL-6 but no detectable IL-6 in the aqueous humor and the absence of uveitis. Intravitreal injection of endotoxin-free human recombinant IL-6 (10-10(5) U) in rats resulted in uveitis, resembling the ocular response to endotoxin. There appeared to be a prozone effect regarding the total aqueous-humor protein concentration. The largest amount of aqueous-humor protein was seen in the eyes injected with 10(2) U of IL-6, but increasing concentrations of intravitreal IL-6 showed a corresponding decrease in protein levels. In the fellow saline-injected eyes, a clear consensual response was observed with regard to the extravasation of protein, although the uveitic grade in these eyes was low or zero. Repeated intravitreal injection of IL-6 resulted in ocular unresponsiveness in nine of 11 rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

SDS-Minigel electrophoresis of human tears. Effect of sample treatment on protein patterns.

An automated Minigel electrophoresis system (PhastSystem, Pharmacia, Uppsala, Sweden) was tested for human tear protein analysis. Tear samples were treated under nonreducing or reducing conditions before sodium dodecyl sulphate polyacryl amide gel electrophoresis (SDS-PAGE). Micro-amounts of tears (2 microliters) were sufficient for analysis and separation and visualization of proteins were completed within 2 hr. Tear proteins were identified using purified control proteins and immunoblotting techniques, using antisera against immunoglobulin (Ig) A (alpha) heavy chains, Ig heavy and light chains, secretory components and lactoferrin. In nonreduced tears, lactoferrin (seen as a double band), serum albumin, tear-specific prealbumin (TSPA), and lysozyme were clearly separated. Secretory IgA (sIgA) was seen as a smear on top of the gel. Immunostaining also showed a major Ig light chain containing protein. After reduction, the protein profiles showed marked changes. In reduced tears, immunoglobulin heavy and light chains (molecular weight [MW]: 64 and 28 kD, respectively) were detected on the SDS-PAGE profile after immunostaining, and represented disulfide cleavage fragments, which originated from sIgA. Reduction resulted in the liberation of the secretory component piece (MW: 85 kD), which was found to co-migrate with the tear lactoferrin bands. Both lactoferrin and serum albumin acted as larger proteins on SDS-PAGE after reduction. The authors found that the two methods of sample treatment, before electrophoresis, resulted in marked differences on the electropherograms.

Electrophoresis, Polyacrylamide Gel↗

PubMed1990

Use of the Megasoft Bandage Lens for treatment of complications after trabeculectomy.

Shallow anterior chambers and leaking filtration blebs are possible complications after trabeculectomy that can be treated with therapeutic contact lenses. In most cases, however, treatment fails because these lenses are not large enough to cover the filtering bleb. We evaluated the use of a newly developed large diameter (20.5 mm) therapeutic soft contact lens. Five patients with shallow anterior chambers and ten patients with leaking filtering blebs after trabeculectomy were fitted with this new extended-wear contact lens. All patients with shallow anterior chambers developed deep chambers after a mean treatment period of five days. Of the ten patients with leaking filtering blebs, in eight (80%) the leak closed after a mean treatment period of 2.2 months. The contact lens used was comfortable and complications occurred in only one eye. This new therapeutic device is an improvement in the treatment of complications after trabeculectomy.

Adult↗

PubMed1990

Immunohistochemical analysis of iris biopsy specimens from patients with Fuchs' heterochromic cyclitis.

Using immunohistochemical techniques, we analyzed iris biopsy specimens from eight patients with Fuchs' heterochromic cyclitis, seven patients with various other types of uveitis, and eight glaucoma patients without uveitis. No specific abnormalities related to Fuchs' heterochromic cyclitis could be detected. Four of the patients with Fuchs' heterochromic cyclitis and four of the patients with uveitis showed evidence of an inflammatory cell infiltrate, which was a mixture of interleukin-2 receptor-negative T helper and suppressor cells, B lymphocytes, and plasma cells. Only an occasional T lymphocyte could be seen in two of the patients without uveitis. The class II antigen HLA-DR was expressed on iris stromal cells in every patient in the Fuchs' heterochromic cyclitis group and uveitis group and in six of the patients in the nonuveitis group. In six of the Fuchs' heterochromic cyclitis patients, including two without immunohistochemical evidence of inflammatory cell infiltrate, histologic abnormalities were present on hematoxylin and eosin sections.

Adult↗

PubMed1990

Graves' ophthalmopathy: what is the evidence for extraocular muscle specific autoantibodies.

Graves' ophthalmopathy is thought to be an autoimmune disease. Whether this disease is organ specific or one of the manifestations of the closely linked Graves' thyroid disease is still a matter of speculation. Many papers describe autoimmunity to orbital antigens, in particular to extraocular muscles, in patients with Graves' ophthalmopathy. In this paper we have tried to give an overview of the evidence for circulating antibodies against extraocular muscle antigens and to discuss their significance in relation to the immunopathogenesis of the disease.

Animals↗

PubMed1990

Laboratory tests in uveitis. New developments in the analysis of local antibody production.

Analysis of local intraocular antibody production is a valuable tool with which to confirm a suspected clinical diagnosis in uveitis. We have analysed paired serum and aqueous samples for the presence of specific antibodies against toxoplasma, cytomegalovirus, herpes simplex virus and varicella zoster virus. Of the patients retrospectively diagnosed as having toxoplasma chorioretinitis 75% had a positive antibody coefficient indicating specific antibody production in the eye. Local antibody production in the eye directed against CMV confirmed the suspected diagnosis of CMV retinitis in 50% of the AIDS patients investigated. So far we have not been able to demonstrate local antibody production against herpes simplex virus (26 samples tested). Two of three patients with acute retinal necrosis had a positive antibody coefficient against varicella zoster virus. Both of these patients had an even higher titer in the aqueous than in serum. Since the choice of therapy, in infectious uveitis, depends on the causative organisms, it is very important to confirm a suspected clinical diagnosis by means of aqueous humor analysis.

Antibodies, Protozoan↗

PubMed1990

Sialic acid in human tear fluid.

A simple assay for the determination of sialic acid (N-acetylneuraminic acid) in human tear fluid was evaluated. Sialic acid, terminally bound on carbohydrate side-chains of glycoproteins, was released after treatment with neuraminidase and measured by an enzymatic colorimetric test. Tear fluid samples were collected from ten healthy adults, using glass capillaries and cellulose sponges. Sialic acid levels in tears collected with sponges (0.8-1.8 mmol l-1) did not differ significantly from those found in capillary tears (0.9-1.8 mmol l-1). Sialic acid, expressed as mmol g-1 protein, was significantly lower in tears collected with sponges (0.18-0.32 mmol g-1) than with capillaries (0.19-0.42 mmol g-1). Recovery of sialic acid and protein after incubation of cellulose sponges with tears was more than 99%. Sialic acid levels in human tears, which had been centrifuged to remove insoluble material, remained unchanged. Furthermore, tear sialic acid activity did not pass a filter with a molecular weight cut-off point of 10,000. Our data indicate that with the assay used in this report, sialic acid in tears is not due to secretory immunoglobulin A (sIgA), lactoferrin and lysozyme. The fact that the major tear proteins do not contribute to the sialic acid levels detected in tears suggests that other as yet unknown soluble glycoproteins are involved.

Adult↗

PubMed1990

The value of laboratory testing in uveitis.

Accurate diagnosis of uveitis is of great importance since the treatment for the various uveitis entities may differ considerably. In a large number of cases the clinical picture is sufficient to make an adequate diagnosis. There are cases in which the diagnosis cannot be made on clinical grounds alone and support is needed from laboratory tests. Only a limited number of tests have been proven to be useful as a diagnostic or prognostic aid. These include HLA-B27 typing in patients presenting with anterior uveitis and testing for angiotensin converting enzyme and lysozyme in case of suspected sarcoid uveitis. Toxoplasma serology is only useful to exclude the diagnosis and a positive test has very low specific value. Analysis of local intraocular antibody production is a valuable tool to confirm a suspected clinical diagnosis in uveitis. It is now possible to analyse paired serum and aqueous samples for the presence of specific antibodies against toxoplasma, cytomegalovirus, herpes simplex virus and varicella zoster virus using commercially available kits. Of the patients retrospectively diagnosed as having toxoplasma chorioretinitis 75% were shown to have a positive antibody coefficient indicating specific intraocular antibody production. Local antibody production in the eye directed against CMV confirmed the suspected diagnosis of CMV retinitis in 50% of the AIDS patients investigated. Until now we have not been able to measure local antibody production against herpes simplex virus (26 samples tested). Two of three patients with acute retinal necrosis had a positive antibody coefficient against varicella zoster virus. Both of these patients even had a higher titre in the aqueous than in serum. Since the choice of treatment, in infectious uveitis, depends on the causative organisms, it is very important to confirm a suspected clinical diagnosis with aqueous humor analysis.

Antibodies, Protozoan↗

PubMed1990

Cyclosporin in the treatment of severe chronic idiopathic uveitis.

In a randomised double-masked study of 27 patients with a severe chronic idiopathic uveitis we evaluated the efficacy, safety, and tolerability of cyclosporin. All received prednisone in a low dose (0.3 mg/kg/day). In 14 patients this was combined with cyclosporin in a single daily dose of 10 mg/kg/day, while 13 patients received a placebo. The dosages were tapered off in accordance with a protocol, and we compared the number of months of successful therapy before the uveitis relapsed. The efficacy results, as expressed in a Kaplan-Meier curve, were in favour of cyclosporin. Owing to the small sample size, however, this difference did not reach statistical significance. The immunosuppressive effect of cyclosporin was not permanent, and in all but one patient the intraocular inflammation relapsed on reduction of dosage. Rather small cumulative doses of cyclosporin proved to be nephrotoxic, but subjective tolerability for cyclosporin was good.

Adult↗

PubMed1990

Detection of locally produced antibodies to herpes viruses in the aqueous of patients with acquired immune deficiency syndrome (AIDS) or acute retinal necrosis syndrome (ARN).

Intraocular synthesis of IgG antibodies against HSV (herpes simplex virus), CMV (cytomegalovirus) and VZV (varicella zoster virus) is considered as an indirect proof of uveoretinal infection. Paired serum and aqueous samples obtained from 16 patients with retinitis associated with AIDS, 3 patients with ARN, 8 patients with posterior uveitis not related to AIDS or ARN and 5 patients with senile cataract were tested for total immunoglobulin G levels and antibodies to HSV, CMV and VZV by the fixed cell immunofluorescence technique. Since therapy must often be started before results of cultures are available, rapid detection of locally produced anti-Herpes Virus antibodies can be a precious tool in the diagnosis of ocular viral infection. Using this technique we were able to confirm the clinically suspected diagnosis in more than 50% of AIDS patients with retinitis and in two out of three patients with ARN.

Acquired Immunodeficiency Syndrome↗

PubMed1990

Aqueous humour analysis in Fuchs' heterochromic cyclitis.

Aqueous humor from 23 patients with Fuchs' heterochromic cyclitis (FHC) was analysed by a number of immunological methods. Intraocular IgG synthesis was found in 65% of patients and oligoclonal IgG bands, mainly of the IgG1 subclass, identified in 57%. There was a relative increase in IgG1 (P less than 0.01) as compared to patients with senile cataract. Local production of the cytokine Interleukin-6 was demonstrated in 63% of patients (P less than 0.01). Analysis of aqueous by HPLC and SDS-PAGE failed to reveal any abnormalities specific for FHC. These findings add further evidence to the theory of immune dysregulation in this condition.

Adult↗

PubMed1990

Association of birdshot retinochoroidopathy and HLA-A29 antigen.

In 1980 Ryan and Maumenee described a new clinical entity characterized by hypopigmented spots in a typical patterned distribution in association with vitritis and retinal vasculopathy leading to cystoid macular oedema and papilloedema. In a recent study of a large group of European patients (n = 102) with birdshot retinochoroidopathy, the importance of the different clinical manifestations and their diagnostic value were assessed. Data on HLA-A29 typing were obtained in 49 patients with birdshot retinochoroidopathy. We could confirm the high association between HLA-A29 and this disease, as found by Nussenblatt in 1982. In 47 of these patients (95.5%) the HLA-A29 antigen was present. This association is presently the highest HLA class I disease association reported with a relative risk of 224.35.

Choroid Diseases↗

PubMed1990

Humoral and cellular immune reactions against retinal antigens in clinical disease.

Autoimmune reactions against retinal antigens have been suggested to play an important role in clinical uveitis in man. As yet the evidence for this assertion is very weak. Sympathetic Ophthalmia is a disease entity which comes closest to acceptance as an autoimmune disease although the autoantigen involved has not been identified. Both cellular and humoral autoreactivity against retinal antigens have been found both in uveitis patients as well as in healthy controls. Very high levels of retinal antibodies were found in onchocerciasis patients but no relation was observed with the occurrence of chorioretinitis. Differences were observed when testing patient sera against human or bovine retinal antigens (S-antigen or IRBP) emphasizing the need for using human tissue when investigating autoimmune responses. Circumstantial evidence in favor of an autoimmune etiology of uveitis include the morphology of the inflammatory infiltrate, effect of immuno-suppressive therapy and especially the establishment of experimental animal models. The experimental models of S-antigen or IRBP induced uveitis are primarily T cell mediated and also show pineal gland involvement. As yet no "established" human autoimmune disease has been described with a dominant role for T cells. Furthermore there is no evidence for pineal gland involvement in clinical uveitis. Analysis of the specificity of the T cell infiltrate or deposited immunoglobulins obtained from the diseased tissues may provide conclusive evidence for a possible autoimmune character of certain clinical uveitis entities.

Animals↗