Biomedical subjects

M Schrenk

Publications and source records attributed to M Schrenk.

At least 19 recordsLinked to original sources

PubMed2000

A microarray enzyme-linked immunosorbent assay for autoimmune diagnostics.

In order to quantify autoantibodies in the sera of patients with autoimmune disease, we have created a microarray-based immunoassay that allows the simultaneous analysis of 18 known autoantigens. The microarrays contain serial dilutions of the various antigens, thereby allowing accurate determination of autoantibody titer using minimal amounts of serum. The assay is very sensitive and highly specific: as little as 40 fg of a known protein standard can be detected with little or no cross-reactivity to nonspecific proteins. The signal intensities observed from serial dilutions of immobilized antigen correlate well with serial dilutions of autoimmune sera. Miniaturized and highly parallelized immunoassays like these will reduce costs by decreasing reagent consumption and improve efficiency by greatly increasing the number of assays that can be performed with a single serum sample. This system will significantly facilitate and accelerate the diagnostics of autoimmune diseases and can be adapted easily to any other kind of immunoassay.

Antibodies, Antinuclear↗

PubMed1996

[Fluorescence angiography in age-related macular degeneration. Study of the incidence of lesions treatable with coagulation].

BACKGROUND: The treatment of late age-related Macular Degeneration (AMD) according to the results of prospective clinical studies is indicated in classical choroidal neovascularisations (NV), which can be delineated from the center of the fovea. To evaluate the effectiveness of this therapy, the knowledge of the frequency of treatable lesions in the spectrum of late AMD is important. PATIENTS AND METHODS: The frequency of different manifestations of late AMD and of lesions treatable with photocoagulation according to the results of prospective clinical studies was recorded in a consecutive series of 2503 fluorescein angiogramms in patients with symptomatic late AMD. RESULTS: Classical choroidal NV could be detected in 35.4% of the patients. In 5.5% of the patients these NV were extra- or juxtafoveolar and therefore laser treatment could be recommended. 10.2% of the patients demonstrated small (< 1 PD) subfoveal classical NV and 20.4% of the patients showed large (> 1 PD) subfoveal NV or membranes associated with large subfoveal, subretinal hemorrhages. Occult choroidal NV could be seen in 41.8% of the patients. These occult NV were larger 1 PD in 21.9% of the patients and small (< 1 PD) in 19.9% of the patients. Pigment epithial detachments (PED) could be seen in 14.6% of the patients (9.9 vascular PED, 3.7% avascular PED, 1.0% rip of the retinal pigment epithelium). Disciform scars were present in 7.2% of the angiogramms. CONCLUSIONS: The spectrum of late AMD can be differentiated in several clinical features. In this consecutive series of 2503 symptomatic AMD patients only appr. 6%% of the patients could be treated with laser treatment according to the results of prospective clinical studies. Because in addition the success of this treatment is very limited, the development of new therapeutic options is one of the major tasks in ophthalmology.

Aged↗

PubMed1995

[Pterygium excision with intra-operative administration of low dosage mitomycin C].

Pterygium excision with postoperative instillation of mitoymcin C (MMC, 0.4 mg/ml) is encouraging because of the technical simplicity and low recurrence rates, but serious postoperative complications have been described (scleral necrosis, corneal perforation, glaucoma, cataract). The authors studied the efficacy and safety of pterygium excisions with a single intraoperative application of low-dose MMC (0.2 mg/ml). Pterygium excision (bare sclera technique) was performed in 18 patients with primary or recurrent pterygia. MMC (0.2 mg/ml) was applied intraoperatively (5 min) to the exposed sclera. Patients were followed up for signs of recurrence and complications. There were four recurrences (mean follow-up 13.8 months). Postoperative complications consisted of granuloma formation (n = 2). Delayed conjunctival healing was observed in all cases. Scleral necrosis, corneal complications, cataract, or glaucoma were not seen. Intraoperative application of MMC apparently reduces the recurrence rate after pterygium excision. The use of a 0.2 mg/ml concentration of MMC appears to be safe.

Adult↗

PubMed1994

[Ocular involvement in Whipple disease].

PATIENTS AND METHODS We present a 57-year-old white man with progressive deterioration of vision, who had a prolonged history of weakness, migratory arthralgias and loss of weight. Bilateral panuveitis, with iritis, inflammatory vitreous opacities associated with small, round, grayish retinal lesions. The duodenum showed a swollen mucosa, which was flecked over with pinpoint grayish grains. A small-bowel biopsy disclosed PAS-positive granules in the macrophages of the lamina propria mucosa, pathognomonic of Whipple's disease. RESULTS After antibiotic treatment with trimethoprim and sulfamethoxazole there was no relapse of the panuveitis during the follow-up period of 18 months.

Humans↗

PubMed1994

[Argon laser trabeculoplasty in chronic simple glaucoma with visual field defects and papillary damage].

It has been recently demonstrated that the intraocular pressure (IOP) after argon laser trabeculoplasty (ALT) in primary open-angle glaucoma rises in the long term. The present study analysed the effect of the postoperative rise in IOP in 36 patients (group A) with glaucomatous optic nerve damage or visual field defects. The results were compared with those in 37 patients without such glaucomatous damage (group B). The IOP, the cup-disk ratios and the visual fields (Goldmann) were retrospectively studied. All patients were under topical glaucoma medication. At the end of the follow-up (group A 20.2 +/- 3.39 months, group B 17.4 +/- 3.59 months), the IOP was uncontrolled in both study groups, and visual fields and disc cupping had worsened in both groups. The results indicate that ALT should not be considered in patients with optic disc damage or glaucomatous visual field defects.

Aged↗

PubMed1994

[Focal hemorrhagic chorioretinopathy. Clinical differentiation and visual prognosis].

Macular choroidal neovascularization in young adults without any known underlying diseases is referred to under the general term of focal hemorrhagic chorioretinopathy. In endemic areas of the USA an infection with Histoplasma capsulatum is thought to be the causative agent, but in Europe the pathogenesis of this condition is unknown. With the aim of finding how European patients with this disease might be detected by clinical examination and to estimate the prognosis for sight in the affected eye and the fellow eye, a follow-up examination (follow up 1-24 years, mean 7 years) of 88 patients (age 15-48 years, mean 33.6 years) was undertaken. Most patients were between 20 and 40 years of age and mildly myopic. The number of chorioatrophic scars associated with the choroidal neovascularization in particular varied widely between patients. Therefore, this characteristic is most useful for clinical differentiation between patients. In contrast, the development of an atrophic conus at the optic disc was predominantly correlated with worsening myopia. One-third of all patients experienced decreased vision during follow-up. In two-thirds of the group, however, the final vision was still 0.1 or better. The initial visual prognosis in the eye affected was predominantly dependent upon the location of the neovascular membrane in relation to the fovea and therefore upon the possibility of photocoagulation treatment. Long-term follow up in these patients revealed visual acuity decreased further only in eyes with increasing atrophy of the retinal pigment epithelium surrounding the disciform or laser scar. One-fifth of the patients also developed choroidal neovascularization in the fellow eye.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

[Therapy of cystoid diffuse macular edema after uveitis and cataract surgery with the carbonic anhydrase inhibitor acetazolamide (Diamox)].

BACKGROUND: Observations made by Cox, Bird et al. (1988), who first used acetazolamide (Diamox) for treatment of macular edema of various origin in a higher number of patients, let assume a positive effect of this therapy on fluid accumulation specifically inside the inner retinal layers. Based on these studies 15 patients (20 eyes) with cystoid or cystoid-diffuse macular edema were treated with acetazolamide in a pilot-study. MATERIALS AND METHODS: Eleven patients (fifteen eyes) had postuveitic macular edema, four other patients (five eyes) had cystoid edema following cataract surgery. Patients with additional diseases causing macular edema of retinal vascular origin were excluded. The initial dose was 500 mg daily. In one patient responding to therapy the dose was gradually reduced after three weeks down to a minimum of 125 mg every second day. For evaluation of the therapeutical results fluorescein angiography and visual acuity were taken into account. RESULTS: Eleven patients (fourteen out of twenty eyes) showed a distinct therapeutical effect with decrease of macular edema in repeatedly controlled fluorescein angiography. All these patients had a subjective improvement of vision which correlated with an increase of visual acuity in exactly one half of all patients. Therapy was stopped, when the macular edema had still appeared unchanged in angiography after three weeks or when--in spite of fluid reduction in angiography--no improvement of visual acuity could be obtained in the next two months. The maintenance dose showed large individual variation with a minimum of 125 mg every second day and a maximum of 250 mg per day. Attempts to stop therapy resulted in a early reappearance of the edema of original extension with corresponding deterioration of visual acuity and sensitivity of central visual field. In a few patients even the reduction of the dose below the individual maintenance dose could be demonstrated angiographically. All patients were under continuous internal medical control, permanent side-effects of acetazolamide with the doses used in this study were not seen. CONCLUSIONS: The results show that acetazolamide is a basically effective agent against cystoid macular edema and that a therapeutical trial is justified based on the treatment criteria of this study. The factors limiting the therapeutical effect of acetazolamide cannot yet be evaluated on the basis of the small amount of patients in this pilot-study. Considering the patient data a time factor depending on the period between onset of edema-related symptoms and begin of treatment is likely. In the group of unsuccessfully treated cases we had the patients with the longest period of preexisting edema (more than one year) of the study.

Acetazolamide↗

PubMed1983