Biomedical subjects

A Wessing

Publications and source records attributed to A Wessing.

At least 55 records · Page 3Linked to original sources

PubMed1992

Histopathologic findings in eyes treated with a ruthenium plaque for uveal melanoma.

Fifty-six globes that had to be enucleated following ruthenium plaque therapy were examined histopathologically. These eyes account for 10% of all uveal melanomas treated at the University Eye Clinic Essen up until 1985. All but one revealed at least some supposedly viable tumor cells. The most prominent findings within the tumors were tumor cell necrosis, vacuolization and balloon cell degeneration, vascular obstruction and fibrosis of the tumor stroma with accumulation of pigmented macrophages. Tumor necrosis was complete or nearly complete in five cases. Tumor regression correlated with cell type and pigmentary characteristics of the tumor, with epithelioid and heavily pigmented tumor cells being more radiosensitive. Tumor regression was inhomogeneous, possibly due to polyclonality, with tumor cells of varying radiosensitivity, or due to patchy areas of vascular obliteration. Among other ocular structures, extensive subretinal gliosis, chorioretinal atrophy and scarring of the sclera within the field of radiation were observed. Scleral necrosis was present in only five cases and was limited to areas in which the tumor had infiltrated the deep scleral layers. The findings described were considered to reflect radiation injury rather than spontaneous tumor regression when compared to 70 control eyes that had been enucleated without prior treatment for uveal melanoma.

Aged↗

PubMed1992

Correlation between biochemical composition and fluorescein binding of deposits in Bruch's membrane.

PURPOSE: The fluorescence of drusen during fluorescein angiography is believed to have important prognostic and pathogenetic implications in age-related maculopathy. It is believed that deposits containing predominantly neutral lipids would be hydrophobic, resulting in hypofluorescence on fluorescein angiography, while the presence of polar phospholipids would be indicated clinically by hyperfluorescence because of its hydrophilic properties. To identify the potential determinants of fluorescence of drusen and Bruch's membrane, a series of macular specimens from human donors older than 60 years of age was examined. No clinical information was available concerning any previous eye disease. METHODS: In vitro fluorescein binding was recorded microscopically, and the presence of fibronectin was sought by immunohistochemistry. The results were correlated with the proportions of phospholipids to neutral lipids identified by histochemical and biochemical studies. RESULTS: It was found that high content of neutral fats was associated with lack of both fluorescein binding and fibronectin, and, conversely, in those specimens with high proportions of phospholipids, fluorescein binding was strong and fibronectin was present. CONCLUSIONS: These observations support the central hypothesis concerning biophysical changes in Bruch's membrane with age and the potential importance of fluorescein angiography in the characterization of Bruch's membrane deposits.

Aged↗

PubMed1992

[Epiretinal membrane formation after pars plana vitrectomy in proliferative diabetic retinopathy].

Recurrent epiretinal membranes are a major contributing factor to functional and visual failures after pars plana vitrectomy for proliferative vitreoretinal disorders. In this study 222 consecutive eyes that have had pars plana vitrectomy for proliferative diabetic retinopathy (operated in 1986 und 1987) were evaluated retrospectively. The study focuses on a subgroup of 108 consecutive eyes all with preoperative tractional retinal detachment and all operated with primary silicone oil injection. A minimum follow up of six months was present in 90% of these cases. Permanent visual success was observed in 40% of the eyes, most of which had dense vitreous hemorrhage preoperatively. Multivariant analysis revealed that among several potential risk factors recurrent epiretinal membranes as well as silicone oil were significantly associated with visual failure. Because of the high incidence of recurrent epiretinal membranes associated with poor functional results silicone oil injection following pars plana vitrectomy should be employed restrictively in patients with proliferative diabetic retinopathy.

Cataract↗

PubMed1992

Macular disease in an elderly population.

In order to obtain more accurate information concerning the prevalence of macular diseases in an elderly population, a clinical study was undertaken on a sample of 430 members of the general population over the age of 65 years in London. Degenerative age-related macular changes were clinically visible in about 25%, and 2.8% had a lesion causing loss of visual acuity due to macular disease. Age was the only risk factor identified for age-related changes. No correlation was identified with the prevalence of hypertension, smoking, or diabetes mellitus between groups. In addition, symmetry was shown in the number of drusen, as well as their size, density and fluorescence in the central and peripheral areas between the eyes of affected subjects. The prevalence data from this study represent a baseline for the interpretation of hospital-based data and for the planning of health care.

Aged↗

PubMed1992

[The retina].

Explore the source record for details and available documents.

Humans↗

PubMed1992

[The Bruch membrane and choroid. Angiography and functional characteristics in age-related changes].

Age-related changes in the retinal pigment epithelium and Bruch's membrane are believed to play an important role in the pathogenesis of age-related macular degeneration. Ophthalmoscopically visible drusen in the macular area may precede the complications causing visual loss. In addition to these localized depositions of debris in Bruch's membrane, histological methods could demonstrate linear deposits in Bruch's membrane which may also profoundly influence the development of complicated macular aging changes. It is difficult to identify linear deposits clinically, but as an indirect criterion for diffuse thickening and linear deposits in Bruch's membrane regression of the choriocapillaris with consequent prolongation of the choroidal filling phase in fluorescein angiography is suggested. This feature was observed in 26% of elderly patient. In association with these areas of regressed choroidal capillaries, loss of visual function was found in fine matrix perimetry.

Aged↗

PubMed1991

[Indications for coagulation in diabetic maculopathy].

Macular changes of 333 eyes of 266 diabetic patients were analized regarding number of microaneurysms, area of intraretinal lipids and hermorrhages and the amount of leckage and capillary occlusion in fluorescein angiography. The changes were observed in a central and peripheral area centered around the fovea. The distribution of the changes observed were correlated with the visual acuity of the patients. Only the number of peripheral microaneurysms and the presence of foveal intraretinal edema correlated with a reduction in visual acuity. These parameters are therefore clinical indicators for the severity of diabetic maculopathy. Regarding the visual acuity after a minimal follow up of six months the presence of foveal intraretinal edema was the most important factor with a high risk of short term visual loss. The presence of fovealmacular edema might therefore be the most important indicator for macular photocoagulation treatment.

Adolescent↗

PubMed1991

[Exudative retinal detachment, pigment epithelium tear and subretinal exudate in a case of central serous retinopathy].

A thirty year old patient with central serous chorioretinopathy on his right eye is presented. The signs of his disease were exsudative retinal detachment with shifting fluid, rip of the retinal pigmentepithelium and a mass of whitish-yellowish subretinal protein. After the diagnosis was made light-coagulation was performed. Within half a year the retina reattached completely, most of the subretinal protein was reabsorbed and vision slowly normalized.

Adult↗

PubMed1991

Arteriovenous communications of the retina during a 17-year follow-up.

Arteriovenous communications of the retina are rare developmental malformations considered to have a relatively stationary appearance. We observed a young girl with an arteriovenous malformation over a period of 17 years. Episodes of spontaneous regression, marked dilatation, and elongation of previously normal vessels are described.

Arteriovenous Malformations↗

PubMed1991

[Revision operations in retinal redetachment].

We analyzed retrospectively 239 consecutive patients who had undergone reoperation for repeat retinal detachment; 441 repeat operations were performed. The average follow-up was 2.1 years, and on average we noted 1.8 retinal redetachments per patient. At the last follow-up examination in 173 eyes (72.4%), the retina was reattached; 10.5% of the eyes had a partially detached retina and in 15.9% the retina was again completely detached. Enucleation was necessary in 3 eyes (1.2%). Visual improvement occurred in 45% of the eyes with reattachment of the retina. When the first retinal detachment occurred, 74 eyes were aphakic. Compared to the other 165 eyes there was no difference in anatomic or visual outcome. Aphakic eyes needed fewer additional reoperations (39%) compared to the phakic group (50%, p less than 0.01). One important reason for the surgery being unsuccessful was poor placement of the scleral buckle. In both groups equatorial placement of the scleral buckle led to anatomical success in more than 50%. The eyes in the aphakic group required more vitrectomies (47%) compared to the phakic eyes (34%, p less than 0.01).

Adolescent↗

PubMed1990

X-linked congenital retinoschisis.

The natural history and electrophysiological findings of 52 patients with X-linked congenital retinoschisis with a follow-up of up to 26 years are described. The mean visual acuity was reduced to 0.24 +/- 0.2 and remained unchanged in most patients during this time. If visual loss occurred, it usually happened in the first decennium. The complications were retinal detachments in 11% and vitreous hemorrhages in 4% of the eyes. In general, the vitreous hemorrhages resolved spontaneously. Retinal detachments were treated successfully with conventional buckling procedures. Redetachments occurred in about 40%. Prophylactic laser coagulation was of no use because it was complicated by detachment in 43% of our series. The electro-oculogram was usually normal. In addition to the known electrorentinographic findings of normal a-wave and reduced b-wave amplitudes, we found prolonged b-wave latencies and implicit times, as well as a reduced 30 Hz flicker response.

Adolescent↗

PubMed1990

Cone dystrophy and supernormal dark-adapted b-waves in the electroretinogram.

A male patient suffering from cone dystrophy was followed over 9 years. In addition to the typical clinical and electrophysiologic signs, supernormal b-waves were found in the dark-adapted electroretinogram. Our case is compared with 12 similar patients described in the literature. Our patient differed from the other patients in the following aspects: he was male and had a congenital stationary disease with a small pigment epithelial scar in the left eye only and no other fundus changes up to the age of 22 years. He did not complain of night blindness. The dark-adapted electroretinogram of our patient showed a normal b-wave threshold with increased b-wave amplitudes and markedly prolonged b-wave latencies and implicit times. This combination of signs has not been reported to date in any other patient and points towards a postreceptoral defect of the interneuronal connection.

Adolescent↗

PubMed1990

[Cytostatic and immunosuppressive treatment of ocular Behçet syndrome].

Ocular symptoms of Behçet's syndrome in 16 patients and the results of cytostatic and immunosuppressive therapy with cyclosporin A (6 patients), chlorambucil (6 patients), and a combination of cyclophosphamide and procarbacin (4 patients) are described. The clinical course and therapeutic outcome were compared to the patients' visual acuity and the duration of the disease prior to institution of cytostatic therapy. Average follow-up was 4.6 years, maximum 9 years. The principal ocular symptom in all patients was hemorrhagic, occlusive periphlebitis. Other symptoms, in descending order of frequency, were chorioretinitis, iridocyclitis, complicated cataract, secondary glaucoma and exudative retinal detachment. The patients in whom cytostatic therapy was instituted no later than 6 months after onset of the disease showed an improvement in or stabilization of visual acuity, as well as a clear reduction in signs of intraocular inflammation and frequency of recurrence. No improvement in visual acuity or ocular symptoms was achieved in cases where the disease was very advanced, despite cytostatic-immunosuppressive therapy. The results support early institution of immunosuppressive therapy in cases with Behçet's syndrome where severe, irreversible damage has not yet occurred and in which vision is threatened in both eyes. However, due consideration must be given to the potential risks of immunosuppressive therapy, in particular the risk of a malignant tumor.

Acyclovir↗

PubMed1990

Mass dense vacuoles in Drosophila Malpighian tubules contain zinc, not sodium. A reinvestigation by X-ray microanalysis of cryosections.

The intracellular storage of zinc in Malpighian tubules of Drosophila hydei was studied by X-ray microanalysis of freeze-dried cryosections. Mass dense vacuoles in the proximal region of the anterior larval Malpighian tubule cells were found to accumulate zinc, not sodium. The zinc content was enhanced considerably after addition of zinc to the food of the larvae. Zinc-containing vacuoles were also found after pupation. After starvation of larvae in sea water, Na was detected in these vacuoles in addition to Zn. A small increase of Na and a remarkable increase of Zn was found in the vacuoles after injection of Ringer solution with ouabain into the larvae. Similar vacuoles in cells of untreated posterior tubules exhibit only low zinc levels.

Animals↗

PubMed1990

[Non-Hodgkin's lymphoma simulating chorioretinitis].

Lymphoma affecting the eye is a special form of Non-Hodgkin's Lymphoma, which was formerly described as reticulum cell sarcoma and is now mostly identified as highly malignant lymphoma. The clinical findings include posterior uveitis with dense opacities of the vitreous body. We present two female patients with minor opacities of the vitreous body, thus permitting funduscopic inspection and leading to the diagnosis of chorioretinitis. Fundus examination of the first patient revealed confluent infiltrates in both eyes. She developed progressive neurological symptoms within 10 weeks and died of respiratory insufficiency. All parenchymatous organs and the central and peripheral nervous system showed multifocal infiltration with cells deriving from a malignant T-cell lymphoma. The second patient presented with subretinal infiltration surrounding the right optic nerve head. Over the following weeks the infiltrations first spread towards the temporal fundus and then disappeared spontaneously, forming scars with atrophy of the pigment epithelium.

Aged↗

PubMed1990

[Drusen and their significance in age related macular degeneration].

In 81 patients with bilateral drusen and 150 patients with unilateral disciform lesions drusen were analyzed with respect to number, size, density and early and late angiographic behavior. In patients with bilateral drusen excellent symmetry was observed for all parameters. Drusen in fellow eyes of patients with avascular pigment epithelium detachments were larger, more confluent and less fluorescent than drusen in fellow eyes of patients with choroidal neovascularization. These results reveal drusen as products of specific metabolic failures of the pigment epithelium rather than unspecific aging changes. These metabolic failures result in specific individual patterns of drusen, which predispose to the development of specific complications of age-related macular degeneration.

Fluorescein Angiography↗

PubMed1990

[Metastases of malignant extra-ocular tumors to the choroid. Diagnosis and fractionated radiotherapy].

A total of 161 cases of choroidal metastases are reviewed. Breast or bronchial carcinomas are the most frequent primary tumors. One-third of the patients develop bilateral choroidal metastases. In 67% of all cases metastatic choroidal lesions were found in the posterior pole. Eighty-nine percent of all patients had a history of malignant tumor, in 11% of all patients choroidal metastasis was the first sign of a primary carcinoma elsewhere in the body. Sixty percent of all patients with choroidal metastases had additional other distant metastases at the time of diagnosis of choroidal involvement. The survival rate is poor: 50% of all patients with choroidal metastasis had died 1 year later. In 35% of all patients, choroidal metastases occurred despite prior systemic therapy with cytotoxic drugs or hormone therapy. In many cases the spontaneously course leads to irreversible loss of central visual acuity due to tumor growth, tumor necrosis or the complications of an exudative retinal detachment. Early fractionated external beam in radiation may prevent this outcome. The clinical course in 71 eyes following irradiation is reported. In 80% radiation therapy led to regression or eradication of the tumor, and a vision of at least 0.4 was maintained in 61% of the treated eyes.

Breast Neoplasms↗

PubMed1990

[Development and dosimetry of a 125 iodine applicator for brachytherapy of intraocular tumors].

Due to the low gamma energy (27-35 ke V), iodine 125 is especially suitable for brachytherapy of intraocular tumors. 125I is available as encapsulated seeds. Applicators can be individually loaded with these seeds to accommodate the shape of the tumor as much as possible. To measure the depth-dose distribution LiF thermoluminence detectors (TLDs, 1 mm3) are embedded in an RW-1 eye phantom at various distances and directions from the high active plaque positioned at the top of the phantom. To obtain the three-dimensional dose distribution, the TLDs are read after exposure for the appropriate time period. Based on experimental measurements of the 125I plaque, a computer program is developed to calculate the dose distribution within the eye and the radiation time for intraocular tumors. These results are very similar to those obtained when using mathematical equations published in the literature. In summary, three-dimensional dose distribution at various distances from an 125I eye plaque has been experimentally determined using a new method. This is an important prerequisite for introducing 125I plaques into the treatment of intraocular tumors.

Brachytherapy↗