Biomedical subjects
Publications and source records attributed to F Daxecker.
A patient presented in our clinic with impairment of visual acuity due to optic disc and macular oedema. Internal examination revealed chronic lymphatic leukaemia, and the patient was treated with Leukeran and Aprednisolone according to the chemotherapeutic regimen of Knospe. Remission occurred, and the pathological findings of the fundus disappeared.
A Fortran program which can be run on IBM-compatible personal computers has been written for the differential diagnosis of ophthalmologic syndromes. The user enters the symptoms observed and the computer displays a list of syndromes in which these symptoms occur. The program at present covers 219 syndromes and 1094 symptoms, and can be expanded. Its use is expected to make differential diagnosis and the scientific clarification of syndromes easier.
Carcinomas of the cornea have not yet been described in the literature. A 50-year-old man underwent keratoplasty because of corneal dystrophy. Microscopic examination disclosed a squamous-cell carcinoma which had spread over the entire cornea and just reached the limbus.
A Fortran computer program has been written for the differential diagnosis of ophthalmic syndromes. Input for the program are the observed symptoms and the result is a list of syndromes relevant to one or more of the symptoms. The program was written for the Control Data Cyber 840 at the Computer Center of the University of Innsbruck, which is connected permanently by terminals to institutes. A second version of the program has been adapted for IBM-compatible personal computers. At present, the program includes 219 syndromes with their individual symptoms. However, it is possible to supplement or alter the list of syndromes and symptoms. The use of this computer program is expected to make the differential diagnosis easier and to simplify and improve the scientific clarification of syndromes.
A carcinoma of the cornea is rare. A 48-year-old man underwent keratoplasty because of corneal dystrophy. Micro-scopic examination showed a squamous cell carcinoma that had spread over the entire cornea and had just reached the limbus. A conjunctival biopsy was performed. Histological analysis showed conjunctival tissue that was covered with normal epithelium. No carcinoma cells were evident.
Binding proteins for retinoic acid (cellular retinoid acid binding protein, CRABP), and for vitamin A (cellular retinol binding protein, CRBP) have been demonstrated in various cell types; these binding proteins display the characteristics of receptors. In the present study CRABP and CRBP levels were measured in 9 melanomas of the choroid. CRABP was detected in 2 of the melanomas, whereas CRBP was measurable in 1 melanoma. In comparison samples of normal choroid contained CRABP and CRBP in all cases investigated.
The patient, who is now 60, had a nevus and areas of cystic changes in the conjunctiva in her right eye, which had been present from birth to the age of 59. In 1987, rapid tumor growth aroused suspicion that malignant change could be occurring and so the nevus as well as the area of the conjunctiva containing cystic changes were excised. Histological finding: conjunctival malignant melanoma, containing compressed (densely arranged) atypical cells with pleomorphic hyperchromatic nuclei and prominent nucleoli. The biopsy specimen of the conjunctiva showed a typical nevocellular nevus with large inclusion cysts of the conjunctival epithelium.
Cellular retinoic acid-binding proteins (CRABP) and cellular retinol-binding protein (CRBP) can be found in cells and nuclei. They function in the same way as receptors. CRABP and CRBP were studied in 9 cases of choroidal melanoma and in 3 of retinoblastoma. CRABP was found in 2 cases of melanoma and in 3 cases of retinoblastoma. CRBP was found in 1 melanoma.
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A 87-year-old female patient with a squamous cell carcinoma of the conjunctiva was treated with local strontium-90 irradiation (with a so-called 'Dermaplatte'). In spite of a relatively low dosage, radiotherapy was followed by a corneal ulcer with consecutive rupture of the cornea. The cause of this unexpected perforation was, besides the effect of low-dose irradiation, probably a metabolic disorder of the cornea and a disturbance of the tear film due to the carcinoma which had spread on Bowman's layer of the cornea in an exophytic manner and was accompanied by a dense lymphocytic infiltration. An exenteration was performed and, at the last examination (1 year later), no local recurrence could be detected.
Dacryoliths are uncommon and there are only a few reports in the literature. In a patient with recurrent stenosis of the lacrimal drainage system a lacrimal stone (dacryolith) was removed from the lacrimal sac during dacryocystorhinostomy. A histological and immunohistochemical examination was performed and keratin antibodies could be detected. In a chemical analysis calcium, sulfur and some phosphorus were determined as major constituents.
Binding proteins for retinoic acid (cellular retinoic acid binding protein, CRABP) have been demonstrated in various cell types, and display the characteristics of receptors. Three retinoblastomas are described. The clinical diagnosis of retinoblastoma was established by ophthalmoscopic echographic and histological examination. One part of the tumor was frozen in liquid nitrogen immediately after surgery and used for the determination of CRABP. CRABP was present in cells from all three tumors. This may indicate sensitivity of this tumor to retinoic acid or synthetic retinoic acid derivatives with biologic activity.
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Marked inflammation of the cornea (keratitis solaris) is often observed after exposure to strong solar radiation, especially in high altitudes and snow-covered terrain. Using the action spectrum and the solar spectrum, the radiant exposure causing keratitis solaris was calculated for a horizontal surface. The parameters selected were altitude, season, ozone content and albedo. The radiant exposure of the eye increases approximately 16-fold, comparing terrain without snow-cover and terrain with snow-cover. Radiant exposures in clinically observed cases of keratitis solaris were calculated to range from 1200 to 5600 Jm-2. A discussion on these figures with regard to threshold doses shows a significant difference between long-term exposure to solar radiation and short-term exposure to artificial sources.
A case of sympathetic uveitis which developed after several operations to reduce intraocular pressure is reported. Initially there was a thrombosis of the central vein; secondary glaucoma developed after laser coagulation and iridectomy; six operations followed. Some months later the diagnosis of sympathetic uveitis was established. The pathogenesis of sympathetic uveitis in this case is discussed.
Exploration of the optic canal was performed in 5 patients with traumatic amaurosis. Fractures of the optical canal were found in 4 cases. One case in which the canal was intact was interpreted as evulsion of the optic nerve. Vision improved in one of the cases with a fractured optical canal. Exploration of the optic nerve is recommended in cases of traumatic amaurosis, always provided that the indication is correct.
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With the help of the keratitis action spectrum and the solar spectrum for various elevations, the intensity of solar radiation that produces keratitis is calculated depending on altitude for terrain with and without snow cover. There is a 17-fold increase in midday solar intensity from winter to summer. In summer the intensity increases by 16% for every 1000 meters of altitude. For a subject observing snow-covered terrain, the intensity is 16 times greater than when the same terrain is observed without snow cover. For clinically observed cases of photoelectric keratitis caused by solar radiation it is possible to calculate the doses involved. They range between 1200 J/m2 and 5600 J/m2. These values are discussed in terms of a threshold dose, and it is concluded that this threshold dose is much higher than in the case of short-term irradiation such as occurs during welding. The difference between these two threshold doses is presumably explained by a repair mechanism.