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R Krott

Publications and source records attributed to R Krott.

At least 19 recordsLinked to original sources
PubMed2003

[Mydriasis not reacting to light during an uneventful esophagectomy--drug-related side effect of Akrinor?].

We present a 72 year old patient who underwent an esophagectomy uneventfully. At the end of the procedure the anaesthetist diagnosed a mydriasis not reacting to light. The mydriasis lasted for 3 hours. 30 minutes after diagnosis a cranial computed tomography scan showed no abnormalities. The tracheal tube was removed after 16 h of artificial ventilation, the patient was awake and responded to questions. The neurological examination was normal, as well as the control CT scan. With regard to a mydriasis the following differential diagnosis have to be considered: cerebral ischemia, cerebral hematoma, metabolic encephalopathy, shock, and a drug side effect. We state that an alpha-mimetic effect of the drug mixture Akrinor, the patient had received shortly before diagnosis of the mydriasis, is the most likely explanation. One 2 mls syringe contents of 200 mg norephedrine-ethyl-theophylline and 10 mg noradrenaline-ethyl-theophylline.

Aged↗
PubMed2001

Effects of protein tyrosine kinase inhibitor genistein on retinal function in superfused vertebrate retina.

The aim of this study was to evaluate safe concentrations of genistein for a potential intraocular application using the isolated retina technique on bovine retina preparations. Bovine retinas were isolated and perfused with an oxygen pre-equilibrated standard solution. The electroretinogram (ERG) was recorded as a transretinal potential using silver/silver-chloride electrodes. After recording of stable ERG amplitudes, genistein was added to the solution in different concentrations. The percentage of b-wave reduction under the drug was calculated. We also studied the influence of genistein on the a-wave amplitude. After the addition of aspartate, the b-wave amplitude was reduced continuously until unmasked a-wave amplitudes were reached. Genistein was then added to the aspartate containing perfusate. The percentage of a-wave amplitude reduction under the drug was calculated. Concentrations of 3.3 microMol/l and higher were found to reduce the b-wave amplitude. The a-wave amplitude was not changed by the applied concentrations. The ERG only showed toxic effects from genistein beyond concentrations that were found to inhibit endothelial cell growth in vitro. In previous studies, beneficial effects on trabecular meshwork cells were present for genistein concentrations which are distinctly higher than the maximum nontoxic concentration reported here. It was shown that the photoreceptor layer is not affected at the examined concentration range. Therefore, we attribute the toxic effects to postsynaptic interaction of genistein. Intraocular application of genistein in a sufficient concentration seems possible.

Animals↗
PubMed2001

Clinicopathological correlation of retinal pigment epithelial tears in exudative age related macular degeneration: pretear, tear, and scarred tear.

AIMS: To analyse the histopathology of vascularised pigment epithelial detachments and tears of the retinal pigment epithelium (RPE) in age related macular degeneration (AMD). METHODS: The light microscopic architecture of 10 surgically removed subretinal specimens-three vascularised pigment epithelial detachments, four recent tears, and three scarred tears as a manifestation of AMD-were studied and correlated with the angiographic findings. RESULTS: Recent tears: a large fibrovascular membrane was found to be originally situated in Bruch's membrane. About half of the surface of the fibrovascular tissue was denuded of RPE and diffuse drusen. The RPE and diffuse drusen had retracted and rolled up, covering a neighbouring part of the intra-Bruch's fibrovascular membrane. The rolled up RPE and diffuse drusen were not interspersed with fibrovascular tissue but lay superficial to the intra-Bruch's fibrovascular membrane itself. Scarred tears: a collagen capsule surrounded the rolled up diffuse drusen and RPE. Fibrovascular tissue was found inside the rolled up material, predominantly at its choroidal side. CONCLUSION: The area of choroidal neovascularisation associated with a vascularised pigment epithelial detachment and a tear of the RPE may be larger than was hitherto thought or indicated by fluorescein angiography. This neovascular tissue may be present within the bed of the RPE tear, as well as at the site of the scrolled up RPE.

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PubMed2000

[Hyperbaric oxygen therapy in retinal artery occlusion].

UNLABELLED: Retinal artery occlusion (RAO) is an ophthalmological emergency that causes a major decrease of visual parameters in most of the cases. Purpose of this pilot study was to evaluate the effect of adjunctive hyperbaric oxygen therapy (HBO) on visual acuity (VA). PATIENTS AND METHODS: Patients with acute central or branch artery occlusion (CRAO/BRAO) consecutively admitted to our hospital were offered adjunctive HBO. Standard therapy consisted of ocular massage for 3 minutes, paracentesis and intravenous acetazolamide. HBO (3 x 30 minutes at 240 kPa) was applied t.i.d. on the first day, b.i.d. on day 2 and 3 and o.d. for at least another 4 days. Patients who refused HBO or had contraindications served as controls. VA was measured according to the guidelines of ETDRS. The follow up was 3 months. RESULTS: HBO: 8 patients with CRAO showed a mean increase in VA of 1 line, 4 of 8 patients had an increase of 2 lines and more, in 3 of 8 patients VA was unchanged and one patient suffered a decrease of 6 lines. 10 patients with BRAO showed a mean increase in VA of 8 lines, 8 of 10 patients showed an mean increase of 2 and more lines, in 2 of 10 patients VA was unchanged. CONTROLS: 8 Patients with CRAO had a mean increase of 2 lines during follow up, 3 of 8 patients showed an increase of 2 lines and more, in 5 of 8 patients VA was unchanged. 6 patients with BRAO had a mean increase of VA of 4 lines, 3 of 6 patients had an increase of 2 lines and more, one patient lost 3 lines and in 2 patients VA was unchanged. The results are compared to the literature. CONCLUSIONS: HBO seems to be beneficial for VA in eyes with BRAO. Further investigations are necessary to prove this observation.

Acetazolamide↗
PubMed2000

Antiproliferative Wirkung von Genistein auf kultivierte retinale Pigmentepithelzellen vom Schwein.

UNLABELLED: The isoflavonoid genistein is known as a potent inhibitor of proliferation in endothelial cells and in some tumor cell lines in vitro and in vivo. Cell growth arrest is mediated by inhbitor of the tyrosine-kinase receptor, a target for many growth factors such as fibroblast growth factor, platelet-derived growth factor, epidermal growth-factor and vascular endothelial growth factor, which may play a role in the development of proliferative vitreoretinopathy (PVR). In this study we report on the antiproliferative effect of genistein on retinal pigment epithelial cells (RPE), which is the major cell type involved in PVR. METHODS: Cell culture experiments using porcine RPE treated with different concentrations (5 up to 100 microgram/ml) of genistein in minimum essential medium +10% fetal calf serum. Inhibition of proliferation was demonstrated by two different methods: (1) uptake of 5-bromo-2-deoxyuridin (BrdU) in S phase after different exposure times (2) expression of proliferating cell nuclear antigen 72 h after scratching confluent RPE. RESULTS: Exposure of RPE to genistein resulted in a concentration-dependent inhibition of cell proliferation at concentrations over 25 microgram/ml geinistein. BrdU incorporation was reduced to 65% after 24- and 48-hour treatment with 100 microgram/ml genistein in comparison with the untreated cells. Proliferation of RPE growing into the artificial wound was inhibited when cells were exposed for 72 h to more than 25 microgram/ml genistein. CONCLUSIONS: Genistein at concentrations over 25 microgram/ml inhibits RPE proliferation. Further studies will be required to determine the applicability of genistein or other phytoestrogens in order to prevent uncontrolled wound healing processes such as PVR.

Animals↗
PubMed2000

Adjunctive hyperbaric oxygenation in macular edema of vascular origin.

Macular edema (ME) is a primary reason for permanent decreases of visual acuity (VA) in diabetic retinopathy and retinal vein occlusions. The standard treatment (photocoagulation, rheological treatment) provide only a limited success. We have therefore studied the additional use of hyperbaric oxygenation (HBO2) in patients with persistent ME. Five patients (1 female, 4 male; 7 eyes) were treated by adjunctive HBO2. The average age of the patients was 60.6 (38.9-76.8) yr. The VA was measured with Early Treatment Diabetic Retinopathy Study charts before and after HBO2 with a monthly follow up. Fluorescein angiography was performed before and after HBO2 with a follow up every 3 mo. Each patient received 10-30 HBO2 treatments (median 15). The follow-up period was 15 mo. for every patient. The mean increase in VA was 3.5 (2-4) lines after HBO2. Retinal photocoagulation was performed in six eyes. Diabetic macular edemas showed no morphologic change, while ME originating from retinal vein occlusions (CME) regressed. The VA in our patients with ME of vascular origin seemed to improve with HBO2. Photocoagulation was necessary in most cases. Visual function correlated with the angiographic presentation only for CME.

Acetazolamide↗
PubMed1999

External beam radiotherapy for subretinal neovascularization in age-related macular degeneration: is this treatment efficient?

PURPOSE: Control of the natural course of subretinal neovascularization (SRNV) in age-related macular degeneration (AMD) is difficult. Only a subset of patients is suitable for laser coagulation. This prospective study aimed to determine the efficacy and individual benefit of external beam radiotherapy (EBRT). METHODS AND MATERIALS: The prospective trial included 287 patients with subfoveal neovascularization due to AMD which was verified by fluorescein angiography. Patients have been treated between January 1996 and October 1997. All patients received a total dose of 16 Gy in 2-Gy daily fractions with 5-6 MeV photons based on computerized treatment planning in individual head mask fixation. This first analysis is based on 73 patients (50 women, 23 men, median age 74.3 years), with a median follow-up of 13.3 months and a minimum follow-up of 11 months. RESULTS: All patients completed therapy and tolerability was good. First clinical control with second angiography was performed 6 weeks after irradiation, then in 3-month intervals. Eighteen patients with SRNV refusing radiotherapy served as a control group and were matched with 18 irradiated patients. After 7 months median visual acuity (VA) was 20/160 for the irradiated and 20/400 for the untreated patients. One year after radiotherapy final median VA was 20/400 in both groups. CONCLUSION: These results suggest that 16 Gy of conventionally fractionated external beam irradiation slows down the visual loss in exudative AMD for only a few months. Patients' reading vision could not be saved for a long-term run.

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PubMed1999

[Repeat laser coagulation of subretinal neovascularization in age-related macular degeneration].

INTRODUCTION: Retinal laser coagulation (LC) of extrafoveal subretinal neovascularization (SRN) due to age-related macular degeneration (AMD) is the only sure therapy. Diagnostics, therapy and follow-up are presented in a case report. CASE REPORT: A 55-year-old woman had suffered from progressive reduction of visual acuity (with metamorphopsia) in both eyes (LE > RE) for 3 years. In the RE the visual acuity was 0.32 and in the LE 0.05. Funduscopy and fluorescein angiography revealed in both eyes the wet form of AMD. The extrafovealy located SRN of the RE was photocoagulated and had to be retreated three-times in 6 weeks due to persistence. For 8 months the findings in the RE have been stable. VA has been improved to 0.4 and no metamorphopsia has been found. CONCLUSION: Extrafoveal SRN should be treated by LC. Short-term follow-up (including FA) and in most cases several LCs are necessary to close the SRN and save the patients' reading vision.

Female↗
PubMed1999

Long-term fluctuations of the normalised rim/disc area ratio quotient in normal eyes.

BACKGROUND: The assessment of the cup of the optic disc in follow-up of glaucomatous optic nerve heads depends on the variability of the cup area over time. We examined the variability of topographic measurements depending on scan focus settings and evaluated the long-term fluctuations of the normalised rim/disc area ratio quotient of normal subjects for 1 year. METHODS: Part 1. Evaluation of the influence of scan focus and corneal curvature on the number of pixels per millimetre in one emmetropic volunteer. The scan focus was varied using contact lenses of different refraction. Part 2. HRT examinations of the optic nerve head of five eyes of five volunteers were repeatedly recorded during a 12-month period. The contour line from the first mean topographic image was transferred into the following seven mean topographic images of each subject. RESULTS: Part 1. The size of pixels depends on the adjusted scan focus for mean corneal curvature radius between 6 and 9 mm. However, after image to image scaling the size of pixels is nearly independent to the scan focus. Part 2. We found the highest variation of normalised rim/disc area ratio for the location of the temporal horizontal sectors, followed by the temporal inferior and the temporal superior sectors. Variation was smallest in the nasal sectors. Mean fluctuation of the normalised rim/disc area ratio quotient of the 95th percentile was 0.09 following image to image scaling compared to 0.16 when using individual image scaling. CONCLUSION: Scan focus variation during HRT follow-up examinations can influence optic disc parameters, especially when image to image scaling has not been performed. A confidence area of an individual optic disc could now be calculated. These confidence bands could help to distinguish more easily between progress of glaucomatous optic nerve head damage and physiological intertopographic variation of optic cup measurements. A decrease of more than 43% in the fluctuations of the normalised rim/disc area ratio could be achieved using image to image scaling techniques. For that reason follow-up of glaucomatous optic nerve heads should only be performed using this software application.

Adult↗
PubMed1998

The nonradioisotopic representation of differentially expressed mRNA by a combination of RNA fingerprinting and differential display.

In many applications, an understanding of differentially expressed genes in different tissues or owing to an applied stimulus is important. However, the wide use of two rather similar polymerase chain reaction (PCR)-based techniques for the identification of differentially expressed mRNAs (RNA fingerprinting by arbitrarily primed PCR [RAP-PCR] and differential display [DDRT-PCR]) has shown that reproducibility is still a problem. By combining features of both RAP-PCR and DDRT-PCR, a technique has recently been developed that avoids some of the disadvantages, but the use of radioisotopes for band detection still limits its application. We have improved this technique for analyzing differentially expressed mRNA by resolving the amplified products on nondenaturing polyacrylamide gels and subsequently staining the gels with silver nitrate. Our modification allows the identification of differentially expressed bands with a very high accuracy. Therefore these bands can be very easily reamplified and sequenced directly. Subsequently the differential expression can be verified by semiquantitative RT-PCR with specific primers derived from sequence data. These improvements, together with nonradioactive sequencing techniques, make it possible to do DD analysis completely without a health hazardous owing to radioactivity. The nonradioisotopic differentially expressed mRNA-PCR (DEmRNA-PCR) is a reliable and useful modification of available differential expression methods.

Cells, Cultured↗
PubMed1998

External beam radiation in patients suffering from exudative age-related macular degeneration. A matched-pairs study and 1-year clinical follow-up.

BACKGROUND: The aim of this prospective study was to ascertain whether external beam irradiation is effective in patients with subretinal neovascularization (SRN) due to age-related macular degeneration (AMD). METHODS: All patients had subfoveal SRN due to AMD as verified by fluoresceinangiography. Two hundred and eighty-seven patient-eyes were treated by external beam irradiation (total dose of 16 Gy in 2-Gy fractions, 5 times a week) from January 1996. The analysis was restricted to those 73 patients with a minimum follow-up of 11 months. Eighteen patients with subfoveal SRN who refused treatment served as control group (CG). 18 patients of the treatment group (TG) were matched for visual acuity, refraction and extent of SRN. The statistical analysis was performed with the unpaired t-test. RESULTS: The mean age of the CG was 73.9 years (range 66.9-81.3 years) and of the TG 75.6 years (range: 65.7-80.6 years). The median follow-up was 13.5 months (range 11.9-18.4 months) in the CG and 12.9 months (range 11-13.9 months) in the TG. The initial visual acuity (VA) was 20/80 in both groups. After 7 months the follow-up revealed median VA of 20/400 in the CG and 20/160 in the TG (P=0.0335). The final median VA was 20/400 in both groups, with a range from 20/40 to 20/1000 in the CG and from 20/63 to 20/500 in the TG (P=0.2433). The SRN doubled in size during this time in both groups. CONCLUSION: These results suggest that external beam irradiation applied in 2-Gy fractions 5 times a week slows down the visual loss in exudative AMD for a short time. Nevertheless, the patients' reading vision could not be saved in the long term.

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PubMed1997

[Dose-response relationship of trans-scleral contact cyclophotocoagulation].

PURPOSE: In recent years, transscleral contact-cyclophotocoagulation has increasingly been used for the treatment of therapy-refractive glaucomas. The dose-effect correlation varies according to different authors. In this retrospective study, we tried to determine whether there is a dose-effect correlation of transscleral contact-cyclophotocoagulation. METHODS: Following diagnosis, 124 eyes of 113 patients (age range 49.9 +/- 26.5 years) were included in the study. The laser parameters used were reviewed along with the intraocular pressure (IOP) before treatment, after treatment and during the follow-up (mean 6 months). RESULTS: The IOP of 45.2% (56) of 124 eyes was < 22 mmHg. In 25.8% (32 eyes) a retreatment was necessary. No correlation between energy and decrease of IOP was found (Prs = 0.08 nonsignificant, Spearmann rank correlation). The IOP was reduced from 35.8 +/- 10.5 mmHg preoperatively to 26.3 +/- 10.5 mmHg at the end of follow-up (P approximately 0, Wilcoxon test). Therapy could be reduced by up to three antiglaucomatous drugs in therapy-refractive eyes. CONCLUSIONS: These data show that a decrease of about 10 mmHg of the IOP is possible using transscleral contact-cyclophotocoagulation. In therapy-refractive eyes, fewer drugs were needed to reach an IOP < 22 mmHg. Regardless of the diagnosis, a dose-effect correlation between the decrease of IOP and laser energy was not found.

Adult↗
PubMed1997

[Vitrectomy in treatment of eyes with complicated uveitis].

BACKGROUND: Vitrectomy serves as an important treatment modality in uveitis, removing inflamed vitreous body and eliminating secondary complications. The aim of our retrospective study was to evaluate the value of vitrectomy in the treatment of complications in uveitis. PATIENTS AND METHOD: We included 50 eyes of 50 patients suffering from chronic uveitis, which underwent vitrectomy surgery during the period of 1990 to 1993. The study only included patients who had vitrectomy for uveitis for the first time. Indications leading to surgery were density of optic media, retinal detachment, cyclitic or preretinal membranes. The mean follow-up was 455 (range 48-1420) days. RESULTS: Vitrectomy was performed at a mean delay of 452 days after initial presentation. The mean visual acuity at the time of surgery was 0.05. The best visual acuity postoperatively was measured at a mean time of 118 days after vitrectomy. Overall, at the last control, eyes with preoperative retinal detachment presented a much worse final functional result (visual acuity of 0.02) than eyes without detachment (visual acuity of 0.5). Ten eyes resulted in hypotonia after surgery (7 eyes with persisting hypotonia). Most frequent complications in the postoperative course were macular pucker (11 eyes), secondary glaucoma (10 eyes), macular edema (6 eyes) and retinal detachment (6 eyes). Fifty percent of all complications occurred within the first 3 months following surgery. CONCLUSION: Vitrectomy leads to a permanent increase in visual acuity through the treatment of complications, on the condition that a stable retinal situation was present preoperatively.

Adult↗
PubMed1997

Orbital emphysema as a complication of bungee jumping.

Bungee jumping is a dangerous sport with increasing popularity in the western world. We report the case of a 28-yr-old man who sustained an orbital emphysema as a result of bungee jumping. He jumped head first from a 160-ft high bridge over a river. At the end of the jump he dived into the water with his head in a reclined position. The sudden dive into the water caused an increase of the air pressure in the nose and paranasal sinuses, which led to an emphysema of the right orbit resulting from a skull fracture not detectable by x-ray. The patient was treated with oral antibiotics. Five days later, he had no clinical complaints and the ophthalmologic examination was normal. This variation of bungee jumping may bear severe risk factors for health in addition to those known from the classic jumps.

Adult↗