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A C Breebaart

Publications and source records attributed to A C Breebaart.

31 records · Page 2Linked to original sources
PubMed1988

Factors influencing the quantitative determination of tear proteins by high performance liquid chromatography.

HPLC analysis of human tears allows tear protein profiles to be obtained within ten minutes. A tear protein profile normally consists of 4 major peaks: IgA, lactoferrin, protein G and lysozyme. Although it is a rapid method, the use of High Performance Liquid Chromatography in the (quantitative) determination of proteins in tears is influenced by various factors. The day to day variability of the quantitative use, ranges between 7 and 9% for the various tear proteins. Combining the HPLC method with a convenient collection method such as sponges or Schirmer strips, showed that the sponges and some of the Schirmer strips used in this study eluted significant material absorbing light at 280 nm. No statistical difference was observed in the HPLC protein profiles of tears collected with Schirmer strips or with sponges. Using sponges has the advantage that they can absorb almost twice as much tears in a same period of time as Schirmer strips. HPLC analysis of human tear proteins is not accurate when there is albumin leakage as in traumatic sampling with Schirmer strips or in inflammatory states. The I-125 column which was used in our study is not able to separate lactoferrin and albumin, which may cause an overestimation of lactoferrin in inflammatory conditions. The study presented here indicates that for quantitative use of HPLC in epidemiological tear protein research better separating protein gel filtration columns are needed.

Adult↗
PubMed1986

Aqueous chamber taps in toxoplasmic chorioretinitis.

The clinical value of the determination of toxoplasma antibodies in anterior chamber taps was evaluated in 12 posterior uveitis patients suspected of a toxoplasmic retinochoroiditis, in four patients with Fuchs's heterochromia and in 31 cataract patients. The posterior uveitis patients all had marked inflammation of the vitreous obstructing the examination of the fundus of the time of aqueous humour aspiration. The clinical diagnosis toxoplasmic uveitis (n = 9) was made after the inflammation of the vitreous had subsided and fundus examination became possible again. Paired serum and aqueous samples were tested for total immunoglobulin levels and toxoplasma antibodies. Eight of the nine clinical toxoplasmic uveitis patients had detectable toxoplasma antibodies in their aqueous, whereas none of the other seven uveitis patients were positive. All of these eight toxoplasmic uveitis patients had a coefficient above 1.5. Of the 31 control patients only one had a positive antibody titer at a dilution of 1/2 with a corresponding coefficient of 1.1. This study shows that aqueous humour examination for toxoplasma antibodies is a valuable diagnostic tool in a selected group of posterior uveitis patients.

Antibodies↗
PubMed1986

Expression of HLA antigens in paraffin sections of uveal melanomas.

Expression of histocompatibility (HLA) antigens on tumor cells may influence the recognition of these tumor cells by the immune system. Immunological recognition may influence tumor growth and patient survival. Although HLA class I and II antigens are known to be present on several tissues in the eye, their presence on ocular tumors had not yet been demonstrated. We studied the expression of these antigens on paraffin preparations of uveal melanomas. Most tumors carried class I and beta 2m antigens on most of their cells while class II antigens were less often expressed. No association with tumor cell type or tumor size was observed. Further studies will be necessary to determine the relevance of different levels of antigen expression with regard to patient survival.

HLA Antigens↗
PubMed1986

Quantitative determination of S-antigen in human ocular tissues, aqueous humour and serum.

Retinal S-antigen is thought to play an important role in the immunopathogenesis of uveitis. To investigate whether S-antigen is a sequestered antigen confined to the retina, a sensitive ELISA was developed to determine the levels of this protein in various human ocular tissues, aqueous humour and serum. The ELISA was performed by incubating S-antigen-containing samples with solid-phase bound immunospecific rabbit anti human S-antigen F(ab')2 fragments and then incubating the bound S-antigen with mouse anti bovine S-antigen serum and the bound mouse antibodies with peroxidase-labelled rabbit anti mouse IgG; the peroxidase activity is developed with ABTS. This method was demonstrated to be highly sensitive and specific: S-antigen could be measured at concentrations of 5-10 nanograms per ml, irrespective of whether it was present in buffer, undiluted whole serum of tissue extracts. Human retinas were shown to contain approximately 1.2 mg immunoreactive S-antigen per retina. Of the other human ocular tissues, only the vitreous and choroid (including pigment epithelium) contained small amounts of S-antigen. Low levels of S-antigen could also be detected in the aqueous humour of two out of seven patients with posterior uveitis. No immunoreactive S-antigen could be detected in the serum of either healthy individuals or patients with uveitis. Sera collected from diabetic patients 15 minutes after extensive laser photocoagulation also did not contain immunoreactive S-antigen. Preliminary experiments with rats to study the clearance of intravenously injected S-antigen from the circulation indicated that the relatively short half-life (+/- 30 min) of circulating S-antigen might account for the absence of detectable S-antigen in the patient sera.

Animals↗
PubMed1982

Lens implant surgery in a developing country.

Unilateral, mostly traumatic cataract in children and adults is considered a good indication for lens implant surgery in developing countries. In Suriname fourteen patients with unilateral, non-senile cataract underwent pseudophakos surgery from 1975 to 1980. No major complications occurred. In ten of the fourteen patients good binocular vision was achieved. Two patients had good visual acuity with poor focus. One patient had persistent deprivation amblyopia. Six patients were ultimately lost to follow-up.

Adolescent↗
PubMedDate not supplied

Analysis of human tear protein profiles using high performance liquid chromatography (HPLC).

Using high performance liquid chromatography (HPLC) the tear protein profiles were measured in controls, patients with Sjögren's disease, questionable dry eye (idiopathic dry eye), idiopathic chronic conjunctivitis and the corneal melting syndrome. Qualitative comparison of the protein profiles of patients with Sjögren's disease, corneal melting and IgA deficiency shows a marked difference in the heights of various peaks as compared to the profiles of the control group. The total protein content of tears in controls and in patients with idiopathic chronic conjunctivitis is age dependent and appears to increase until the age of 40 and to decrease afterwards. The peaks containing IgA, lactoferrin and lysozyme were measured in various eye diseases. In idiopathic chronic conjunctivitis and in the corneal melting syndrome no differences were seen in comparison with controls. In patients with idiopathic dry eye and Sjögren's disease a marked decrease in the three proteins was seen. The study presented here indicates that the HPLC analysis of tears is a promising technique which may increase our knowledge of this ocular fluid.

Adolescent↗
PubMedDate not supplied

16-year remission of rheumatoid arthritis after unusually vigorous treatment of closed dental foci.

This report describes a remission of rheumatoid arthritis (RA) of 16 years duration, apparently caused by the extraction of endodontically well-treated, healthy looking teeth. The only clue that the teeth were contributing to the disease pathogenesis in this case of RA was that the patient was able to reproducibly induce severe attacks of arthritis after prolonged, heavy pressure on some of his teeth treated with root canal fillings. After extraction, a small pus layer was found to cover the apices of the clinically healthy looking teeth. The rheumatoid factor (RF) became negative and the patient remained symptom free for the next 16 years. The possible connections between micro-organisms in closed dental foci under constant pressure and the chronicity and exacerbations of RA are discussed.

Aged↗