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Biomedical subjects

F Koenig

Publications and source records attributed to F Koenig.

At least 19 recordsLinked to original sources
PubMed1990

The pretear characteristics of pigment epithelial detachments. A study of 40 eyes.

Retinal pigment epithelial tears are a major complication of pigment epithelial detachment (PED) in the elderly. We observed the pretear process of PED in 38 patients (40 eyes) to identify characteristic angiographic changes. Before the tear occurred, the filling pattern of the PED underwent alterations, including an increase in the size and a modification in the shape of the PED (27 eyes); the development of notches (14 eyes); and the onset or increase of subretinal fluid, hard exudates, and/or hemorrhages (30 eyes). The most noteworthy feature was the uneven filling of the PED, with a remarkably hypofluorescent central area that remained dark until the late angiographic frames (24 eyes). Conversely, hyperfluorescence appeared early at the margins of the PED, increased progressively, and sometimes demonstrated a crenated edge. The high risk of tearing indicates that laser treatment of the retina should be considered carefully in the presence of these angiographic features.

Aged↗
PubMed1990

Occult subretinal new vessels in age-related macular degeneration. Natural History and early laser treatment.

Little information is available on the natural history and no data have been published on laser treatment for occult neovascularization in age-related macular degeneration. The visual and angiographic outcomes were analyzed in 156 patients (82 untreated eyes; 81 treated eyes) with occult neovascularization who were followed for 1 to 8 years. Early laser treatment decreased visual acuity to less than 20/200 in 31 of the treated eyes (38%) compared with 20 of the untreated eyes (25%). Three years after the onset of symptoms, 24 treated eyes (29%) and 31 eyes untreated eyes (38%) retained 20/50 visual acuity or better, whereas their respective initial visual acuities were not statistically different. Severe loss of vision (6 or more lines of visual acuity) occurred in 43 treated eyes (53%) and in 33 untreated eyes (40%) at the end of follow-up (range, 12-84 months). A slow and gradual increase of the disciform lesion was demonstrated on fluorescein angiography in 60 untreated eyes, with subfoveal involvement noted in 39 eyes at the end of follow-up. In the treated group, subfoveal involvement occurred in 53 eyes, after a relatively short time (mean, 4 months). Only 28 of the 81 treated eyes had successful anatomic results. These findings suggested that laser treatment of occult neovascularization immediately after the onset of symptoms should not be recommended.

Aged↗
PubMed1990

Anacystis mutants with different tolerances to DCMU-type herbicides show differences in architecture and dynamics of the photosynthetic apparatus, depending on site and mode of the amino acid exchanges in the D 1 protein.

Mutants of Anacystis R 2 with different amino acid exchanges in positions 255 and/or 264 in copy I of the psbA gene, leading to different tolerances to DCMU-type herbicides, are compared with the respective wild type concerning pigmentation and incorporation of 35S into the D 1 protein upon growth in the presence of [35S]methionine. All mutants have shade-type appearance compared to the wild type, although to different extents depending on site and mode of the amino acid exchange in the D 1 protein. Except for 3 mutants, there is no correlation between shade-type appearance on one hand and resistance towards a certain inhibitor on the other hand. Not only the molar ratio of phycocyanin (PC) to chlorophyll (Chl) is higher in all mutants compared to the respective wild type, but also the rate of synthesis of the D 1 protein. On the background of different levels of total 35S incorporation within 18 min, D 1 synthesis can be related to shade adaptation. Degradation of the D 1 protein remains to be thoroughly studied in this context. No reproducible differences in whole chain electron transport were observed between mutants and wild type.

Amino Acid Sequence↗
PubMed1990

[Scanning laser ophthalmoscopy. Its value in macular diseases].

The scanning laser ophthalmoscope provided a high quality television image of the fundus with minimal illumination of the retina. This new device based on a totally new electro-optical principle allowed a detailed exploration of macular function directly under simultaneous fundus control. The focused beam of a yellow krypton laser (568,2 nm) was swept up and down, rights and links across the fundus to form a raster of parallel lines on the retina. The S.L.O. illuminated only a single retinal point at a time and illumination was reduced to less than 70 microw/cm2 versus 100,000 microns/cm2 for indirect ophthalmoscopy and 4,000,000 microw/cm2 for fluorescein angiography. The intensity of the laser beam could be modified with the microcomputer by means of an acousto-optic modulator. It was possible to produce static or dynamic graphic designs that were simultaneously viewed by the patient and observed by the examiner on the patient's fundus on the video monitor. Further computerized analysis of the videotaped scanning laser ophthalmoscopic images gave a functional retinal map with correction for shifts of stimulus position due to fixational saccadic eye movements. The map showed true retinal location of 1. fixation area; 2. scotoma. The clinical evaluation was completed with 3. measurement of visual acuity in any foveal or parafoveal location. The results of scanning laser ophthalmoscopy were illustrated with the report of datas in a patient with diffuse retinal pigment epithelial decompensation.

Adult↗
PubMed1989

[Eye manifestations of Horton's disease].

Ocular complications occurring in temporal arteritis are of different severities. These manifestations of the disease occurred in a population of 57 patients with diagnosis of temporal arteritis, in 16 of them (28%). The diagnosis was suggested by finding an inflammatory syndrome (high erythrocyte sedimentation rate) and confirmed by temporal artery biopsy. In making this diagnosis, it was helpful to find a history of characteristic temporal headaches, neckache, jaw claudication, fever and malaise or weight loss in addition to polymyalgia and polyarthralgia. 6 patients presented with diplopia and different ocular muscle or nerve palsies. The 10 others came for sudden loss of vision due to ischemic anterior or posterior neuropathy and in one case, central artery obliteration. Prompt treatment with steroids gave good results on oculomotor troubles and in preventing the risk of involvement of the fellow eye. But loss of vision did not regress with this treatment. That means the importance in making this diagnosis and starting very promptly this treatment.

Blepharoptosis↗
PubMed1989

[Retinal pigment epithelial tears after photocoagulation in age-related macular degeneration].

Retinal pigment epithelial tears after photocoagulation for subretinal new-vessels complicating age related macular degeneration were observed in 20 patients between 1980 and 1988. The patients, 4 males and 16 females, aged from 60 to 86 years (mean: 72.5) were followed up between 12 and 53 months (mean: 21 months). Laser photocoagulation was performed for directly visible lacy subretinal new-vessels (6 cases) or vascularized pigment epithelial detachment (10 cases) or both lesions associated (4 cases). Krypton laser (17 cases), blue-green argon laser and/or orange dye laser (625 nm) (3 cases) were applied in one (9 cases) to four sessions. Retreatment (11 cases) was performed for persistent subretinal new-vessels (3 cases) or recurrences (4 cases) or appearance of a pigment epithelial detachment after photocoagulation for isolated SRNV (4 cases). The tear was observed on fluorescein angiography 10 to 180 days after the last session. It was preceded by occurrence of subretinal hemorrhages, increase in size of the PED or newly formed PED. It appeared on the border of the PED (16 cases) usually temporally, or on the immediate border of the laser scar (4 cases). Further evolution was rapidly defavorable with dramatic impairment of vision and constitution of fibrovascular scar in the macular area. Only 4 eyes progressed to flat atrophic scars after retreatment and retained useful central vision (0.1 to 0.2). Factors which could explain this complication following laser treatment of age related macular degeneration are discussed.

Aged↗
PubMed1986

[Erdheim-Chester disease. The multiviceral form presenting as exophthalmos].

Erdheim-Chester disease is a rare visceral xantho-granulomatosis, the 17th case of which is reported here. The initial symptom, bilateral exophthalmos, was uncommon. The picture was completed by a retroperitoneal xanthogranuloma and by bilateral and symmetrical osteosclerosis of the long bones. The lack of X-bodies at electron microscopy differentiated the disease from Hand-Schüller-Christian disease. The patient's condition improved with chemotherapy (vinblastine and doxorubicin) combined with corticosteroid therapy. After a 5-month remission period, he died of an intercurrent infection. No autopsy was performed.

Diagnosis, Differential↗
PubMed1985

[Exudative retinopathy with dominant transmission. Report of a new pedigree].

A family with the syndrome of familial exudative vitreoretinopathy is described. A 7-year-old presented a non-perfused, avascular periphery in the temporal retina. The father is blind and his fundus was described in childhood as showing vitreoretinal traction, retinal telangectasia and temporal fibrotic changes. A cousin of our patient, a 5-year-old girl, was seen with vitreoretinal traction of the posterior pole. Familial exudative vitreoretinopathy is sometimes confused with retrolental fibroplasia. The family history and a fluorescein angiographic study of non-affected members are useful for confirmation of this diagnosis: pathophysiologic mechanisms and optimal treatment of the disease still remain about discussion.

Adult↗