Biocompatibility and bone regeneration with elastin-like recombinamer-based catalyst-free click gels.

Large bone defects are a significant health problem today with various origins, including extensive trauma, tumours, or congenital musculoskeletal disorders. Tissue engineering, and in particular bone tissue engineering, aims to respond to this demand. As such, we propose a specific model based on Elastin-Like Recombinamers-based click-chemistry hydrogels given their high biocompatibility and their potent on bone regeneration effect conferred by different bioactive sequences. In this work we demonstrate, using biochemistry, histology, histomorphometry and imaging techniques, the biocompatibility of our matrix and its potent effect on bone regeneration in a model of bone parietal lesion in female New Zealand rabbits.

Compact, low-cost Ti:Al2O3 laser for in vivo ultrahigh-resolution optical coherence tomography.

A compact, low-cost, prismless Ti:Al2O3 laser with 176-nm bandwidth (FWHM) and 20-mW output power was developed. Ultrahigh-resolution ophthalmic optical coherence tomography (OCT) ex vivo imaging in an animal model with approximately 1.2-microm axial resolution and in vivo imaging in patients with macular pathologies with approximately 3-microm axial resolution were demonstrated. Owing to the pump laser, this light source significantly reduces the cost of broadband OCT systems. Furthermore, the source has great potential for clinical application of spectroscopic and ultrahigh-resolution OCT because of its small footprint (500 mm x 180 mm including the pump laser), user friendliness, stability, and reproducibility.

Influence of viscoelastic substances used in cataract surgery on corneal metabolism and endothelial morphology: comparison of Healon and Viscoat.

PURPOSE: To evaluate the influence of cohesive and dispersive ophthalmic viscosurgical devices (OVDs) on endothelial morphology and corneal metabolism during cataract surgery. SETTING: Department of Ophthalmology, University of Vienna Medical School, Vienna, Austria. METHODS: In this prospective randomized blind study, 50 eyes of 43 patients were randomized into 2 groups before surgery. Phacoemulsification with implantation of a posterior chamber intraocular lens was performed in all patients. In half the patients, sodium hyaluronate 1% (Healon) was used as the OVD and in the other half, sodium hyaluronate 3%-chondroitin sulfate 4% (Viscoat). Corneal metabolism was evaluated by fluorophotometric measurement of corneal autofluorescence. The corneal fluorescence values were corrected for interference by fluorescence of the ocular lens. Specular microscopy (Noncon Robo SP800, Canon) was used to evaluate the endothelial cell density, coefficient of variation, and percentage of hexagonal cells. Examinations were performed preoperatively and 3 days, 1 and 4 weeks, and 3 months postoperatively. RESULTS: There were no significant changes between preoperative and postoperative endothelial cell density measurements in either group (P =.1717). The percentage of hexagonal cells was similar (P =.3489); however, there was a slightly increasing tendency toward polymorphism in both groups. Corneal autofluorescence decreased 3 days after surgery, increased after 1 week, and decreased again subsequently in both groups. There was no significant difference in the influence on corneal metabolism between the 2 OVDs (P =.9899). CONCLUSIONS: There was no significant difference between Healon and Viscoat. Thus, this study did not confirm an advantage of either for endothelial protection of healthy corneas.

The effect of axial length on laser spot size and laser irradiance.

OBJECTIVE: To determine the effect of the axial length of the eye on laser spot size and irradiance. DESIGN: Experimental study using a calibrated Gullstrand-type model eye. METHODS: The model eye, which was fitted with a scale of half circles in the center of the artificial fundus, was first examined using 2 different fundus imaging systems, then with a setup of a slitlamp, 2 indirect condensing laser lenses, and a laser unit with a spot size of up to 7 mm. The axial length of the model eye was set to different values ranging from 20 to 31 mm, and the magnifications of the fundus imaging systems and the laser lenses were calculated and compared for a treatment spot with a diameter of 4 mm. The laser irradiance for treating the spot at different axial lengths was also recorded. RESULTS: Whereas the magnification of a fundus imaging system is inversely related to the axial length, the laser spot size is directly related to axial length when using indirect condensing laser lenses. Therefore, the changes of magnification produced by axial ametropia are mostly compensated, so that the intended size of the treatment spot is obtained even in eyes with a high axial ametropia. The laser irradiance, on the other hand, has a significant variation for the observed range of the axial length. CONCLUSION: Axial length has a significant effect on laser spot size and laser irradiance. CLINICAL RELEVANCE: The effect of axial length on laser spot size and laser irradiance may be ignored when administering photodynamic therapy with verteporfin but has to be considered for transpupillary thermal treatment of choroidal neovascular lesions.

A new colour vision arrangement test to detect functional changes in diabetic macular oedema.

AIM: A study was undertaken to investigate the correlation between colour discrimination tests and the presence of macular oedema in patients with type I diabetes to find a sensitive diagnostic tool for the detection of early functional changes. METHODS: The study was performed in 39 type I diabetic patients, 10 with and 29 without macular oedema. The examination included biomicroscopy, fundus photography of the macula, videofluorescein angiography, the LogMAR visual acuity chart, Farnsworth-Lanthony desaturated D-15 test, and the new Mollon-Reffin "Minimalist" test for colour vision deficiencies version 6.0. RESULTS: A highly significant correlation was found between the tritan value of the Mollon test and the presence of clinically significant macular oedema (p<0.0015), with a high sensitivity (88.9%) and specificity (93.3%). The DD-15 test was not significant (p=0.345) and showed low sensitivity for the presence of macular oedema (36%). All variables concerning the grading of macular oedema showed a highly significant association with the tritan values of the Mollon test (p<0.0001). CONCLUSION: The results suggest that the Mollon-Reffin "Minimalist" test version 6.0 is the best colour discrimination test for detecting macular oedema, with higher specificity and sensitivity than the other methods used in the study.

Biomicroscopic measurement of the optic disc with a high-power positive lens.

PURPOSE: To compare the magnification properties of four different indirect double aspheric fundus examination lenses for clinical disc biometry. METHODS: Experimental study in a model eye. The relationship between the true size of a fundus object and its image was calculated for each fundus lens for an ametropic range between -12.5 and +12.6 D using a slit lamp biomicroscope with adjustable beam length. RESULTS: Equations for determining the correction factor p (degrees per millimeter) were calculated for each fundus lens. The factor can be used in calculations to determine true optic disc size. The total change in magnification of the system from myopia to hyperopia was -21.1% to +24.0% (60-D lens; Volk Opticals, Mentor, OH), -12.9% to +16.2% (Volk super 66 stereo fundus lens), -13.2% to +13.9% (Volk 78-D lens), and -13.3% to +14.0% (Volk super-field NC lens). When the fundus lens position was altered im relation to the model eye by +/-2 mm under myopic conditions, the change in magnification of the system was -4.3% to +5.7% (60-D lens), -4.6% to +6.1% (66 stereo fundus lens), -4.9% to +6.3% (78-D lens), and -5.9% to +7.8% (super-field NC lens). In the hyperopic condition the change was -2.7% to +3.6%, -3.4% to +4.5%, -3.6% to +4.8%, and -4.5% to +6.0%. CONCLUSIONS: The study has shown that the use of a single magnification correction value for each fundus lens may not be appropriate. These findings have important implications for the way in which calculations for determining the true optic disc size and other structures of the posterior pole are performed using indirect biomicroscopy.

Morphologic characteristics of disciform scarring after radiation treatment for age-related macular degeneration.

OBJECTIVE: To investigate the influence of radiation therapy on the development of disciform lesions in patients with age-related macular degeneration (AMD). DESIGN: A prospective, nonrandomized, comparative trial (patient self-controlled). PARTICIPANTS: Forty eyes with exudative AMD involving the central fovea in 40 consecutive patients were enrolled in this study. INTERVENTION: Radiation was administered to the posterior pole with an 8-mV photon beam from a linear accelerator. A dose of 14.4 Gy, 1.8 Gy per day, five fractions per week was delivered through a single port. MAIN OUTCOME MEASURES: The visual acuity and the morphologic characteristics, demonstrated by fundus photography, fluorescein, and indocyanine green angiography, were investigated before treatment and every 3 months after treatment over a period of 24 months. In 10 patients with bilateral disease the disciform lesions were compared. RESULTS: Twenty five patients could be followed regularly over the period of 24 months. The disciform lesions occurring after radiation were classified in three types. Type I (10 patients) was characterized by being smaller than 2 DD in size, with little fibrotic tissue underneath the retina, but pronounced retinal pigment epithelial changes. Type II (seven patients) showed extensive growth of the choroidal neovascularization (CNV) extending to and beyond the arcades with angiographically active loops in the peripheral parts. Eight patients had type III lesions develop characterized by a size greater than 2 DD but fewer than 6 DD and by a different amount of fibrotic tissue, hemorrhage, and lipid. Type I scarring was significantly associated with occult CNV without pigment epithelial detachments, whereas type II scarring was associated with classic CNV at the initial presentation (P<0.05). CONCLUSIONS: Although no severe side effects have been reported after radiation therapy for AMD, a subgroup of patients may experience extensive growth of CNV after radiation, causing greater functional damage than occurs spontaneously.

Resolution-improved dual-beam and standard optical coherence tomography: a comparison.

BACKGROUND: The purpose of the study was to demonstrate the improved axial resolution and longitudinal stability of dual-beam optical coherence tomography (OCT) in comparison to conventional OCT setups used in commercially available OCT instruments. METHODS: The conventional OCT technique is based on an interferometric setup that is rather sensitive to axial eye motions. We have developed a special dual-beam OCT technique which eliminates the influence of axial eye motions. This is achieved by using the anterior corneal surface as the reference surface for the interferometric ranging. To improve the signal quality, the different wavefront curvatures of beams reflected at cornea and retina are matched by a diffractive optical element. To improve the axial resolution, a broadband synthesized light source with an effective bandwidth of 50 nm is used, and the group dispersion of the ocular media is compensated. Tomographic images were recorded in the fovea and the optic nerve head of healthy volunteers. For comparison purposes, approximately the same locations in the same eyes were imaged by a commercially available OCT instrument. RESULTS: Compared to the standard OCT technique, the dual-beam OCT images show considerably improved axial resolution. Especially in tomograms recorded at the fovea, dual-beam OCT resolves microstructural details that are not visible in the standard OCT images. Furthermore, the axial stability of dual-beam OCT enables the recording of exact geometrical contours of fundus layers. CONCLUSIONS: Dual-beam OCT is able to provide structural information on the ocular fundus that is not obtained with standard OCT. The long recording times of our instrument limit the transverse resolution to 100-150 microm at present.

Intravitreal injection of tissue plasminogen activator and gas in subretinal hemorrhage caused by age-related macular degeneration.

PURPOSE: To assess the efficacy and safety of intravitreal injection of recombinant tissue plasminogen activator and sulfur hexafluoride gas for displacement of subretinal hemorrhages in patients with age-related macular degeneration. METHODS: The authors injected 25 microg of recombinant tissue plasminogen activator and 0.5 mL sulfur hexafluoride gas intravitreally in 11 patients with subretinal hemorrhages of less than 3 weeks duration. Anatomic and functional results were evaluated. RESULTS: Displacement of subretinal blood was successful within the first week after surgery in 10 of 11 patients. This was accompanied by visual improvement in eight patients. After 1 year, visual acuity was better than before surgery in five patients. Diagnosis of a choroidal neovascularization by fluorescein angiography was possible in all patients, and was treated with laser photocoagulation in five. The authors observed no adverse effects of treatment. CONCLUSION: Recombinant tissue plasminogen activator and gas effectively displace subretinal blood in patients with age-related macular degeneration. Randomized studies are necessary to prove the benefit of this simple and safe method in patients with subretinal hemorrhage due to age-related macular degeneration.

Normalization of orbital arterial blood flow in non-ischemic central retinal vein occlusion after 6 months.

INTRODUCTION: Central retinal vein occlusion (CRVO) is a common vascular disorder and may lead to blindness. The aim of the study was to obtain information about the possible imbalance and recovery of orbital arterial blood flow in non-ischemic CRVO. METHODS: Vascular resistance (pulsatility index-PI) in the orbital arteries of 14 patients with non-ischemic CRVO was examined within 3 weeks after onset of CRVO and 6 months later. The control group consisted of 14 age- and sex-matched healthy control eyes. RESULTS: PI was increased in all orbital arteries of CRVO eyes measured within 3 weeks after the onset. Normal PI values were recorded in the same retrobulbar arteries, and re-measured 6 months later. DISCUSSION: There is an increase in vascular resistance in all orbital arteries at the onset of non-ischemic CRVO, followed by a recovery of vascular resistance to normal levels 6 months later. The increase at the onset may be caused by arterial vasospasm or by intraocular hemostasis affecting the afferent arteries.

[Results of fundus perimetry after resorbed premacular hemorrhages under the internal limiting membrane in 10 patients]. / Ergebnisse der Fundusperimetrie nach resorbierten prämakulären Sublimitansblutungen bei 10 Patienten.

BACKGROUND: During their acute phase, premacular hemorrhages under the internal limiting membrane induce an absolute scotoma. It is generally suspected that extravasal blood has a toxic effect on the neuroretina. The objective of this study is to investigate whether one can indeed detect sensoric defects after resorbed hemorrhages under the internal limiting membrane. MATERIALS AND METHODS: Our patient group consisted of 10 patients with resorbed premacular hemorrhages, which had been caused by either Vasalva-Manouver or arterial macroaneurysms. In order to avoid visual field defects due to other causes, patients with diabetes, retinal vein occlusion and glaucoma were excluded from this study. The investigation was carried out with the Scotometry Programme Vers. 2.01 of the Rodenstock Scanning Laser Ophthalmoscope. Furthermore, fundus photographs were taken. RESULTS: Under condition of no pre-existing retinal pathologies, no scotomas could be revealed at the site of the preretinal hemorrhage after full resorption. Relative or absolute scotomas could only be found in cases of pre-existing epiretinal gliosis, pigmentepitheliumdefect, persistent subretinal hemorrhages or scars. CONCLUSION: Since no sensoric defects of the retinal receptors could be detected, the hypothesis of the extravasal blood having a direct toxic effect on the neuroretina, could not be confirmed in this patient group.

Urografía por RM: un método alternativo en la evaluación en pediatría del aparato urinario / MR urography: imaging alternative procedure of the urinary tract in childhood

Tomando como base las secuencias conocidas como RARE, las RM urográficas, se ha planteado como un método alternativo en la evaluación del aparato urinario. Se evaluaron 16 pacientes pediátricos, 11 niñas y 5 varones, con edades entre 4 meses y 14 años. Se investigaron: a) dilatación de la vía excretora, (6 pacientes); b) evaluación de estenosis pieloureterales, 2; c) evaluación postquirúrgica de estenosis pieloureterales, 1; d) riñón en herradura, 1; e) doble vía excretora, 3; f) en reemplazo de U.E., 2 y g) síndrome de regresión caudal, 1 paciente. Se evaluaron en forma adecuada las uropatías obstructivas, determinándose en forma exacta el punto de obstrucción, no así su causa; se logró con las imágenes obtenidas, adecuada discriminación anatómica córtico medular; también fueron satisfactorios los resultados en la evaluación de malformaciones del tipo riñón en herradura y síndrome de regresión caudal. Contrariamente no fueron buenos los resultados en la evaluación de la vía excretora. En conclusión, la RM urográfica actualmente puede ser considerada, un método válido para el estudio del tracto urinario, llegando a reemplazar al U.E. en situaciones específicas; las principales objeciones al método son su costo, las dificultades que presenta en la evaluación de vía excretora no dilatada y la necesidad de anestesiar a los menores de 5 años

Oral zinc and the second eye in age-related macular degeneration.

PURPOSE: To investigate the short-term effect of oral zinc substitution on the development of age-related macular degeneration in the second eye of patients with an exudative form of the disease in the first eye. METHODS: A 2-year, double-masked, randomized, placebo-controlled study including 112 white patients with age-related macular degeneration and exudative lesions (choroidal neovascularization, pigment epithelial detachment, or both) in one eye and a visual acuity of better than 20/40 and macular degeneration without any exudative lesion in the second eye was performed. Patients received either 200 mg of oral zinc sulfate or placebo once daily for 24 months. The main outcome parameters were visual acuity, contrast sensitivity, color discrimination, and retinal grating acuity, as well as serum levels of zinc and copper, red blood cell count, hemoglobin, and morphologic changes detected by grading of monochrome fundus photographs and fluorescein angiograms. RESULTS: In the treatment group, the mean zinc serum level increased significantly (P < 0.0001) from 79 +/- 10 micrograms/dl to 108 +/- 26 micrograms/dl compared to no change (82 +/- 16 micrograms/dl to 85 +/- 10 micrograms/dl) in the placebo group. Serum levels of copper, hemoglobin, and red blood cell count did not change significantly in either group. A choroidal neovascular membrane (CNV) was detected in 14 patients during the treatment period (nine in the treatment group, five in the placebo group). Seven additional patients (three in the treatment group, four in the placebo group) experienced visual loss caused by CNV, and in two patients (one in each group), serous pigment epithelial detachment developed without angiographic evidence of CNV after the end of treatment, during a mean additional follow-up time of 20.8 +/- 8.2 months. In eyes in which exudative lesions did not develop, there was no significant change in any of the functional parameters during the 24-month treatment period, but there was a significant increase in the nonexudative alterations (drusen size, drusen confluence, hyperpigmentation, and focal degeneration of the retinal pigment epithelium) in both groups. CONCLUSIONS: Oral zinc substitution has no short-term effect on the course of age-related macular degeneration in patients who have an exudative form of the disease in one eye.

[Secondary prevention of diabetic retinopathy in type I diabetes mellitus. Dependence on retinopathy status before the intervention]. / Sekundärprävention der diabetischen Retinopathie bei Diabetes mellitus Type I. Abhängigkeit vom Retinopathiestatus vor der Intervention.

OBJECTIVE: To assess prospectively the effect of improving the metabolic state on the course of diabetic retinopathy in relation to the extent of retinal changes before intervention. PATIENTS AND METHODS: 140 patients with type I (insulin-dependent) diabetes mellitus (IDDM) (55 men, 85 women; mean age 30 +/- 11 years; mean duration of illness 11 +/- 8 years), underwent intensified insulin treatment and were then followed for 4 years. At the beginning of the trial fundoscopy was unremarkable in 68 patients (stage 0), a few microaneurysms and (or) punctate bleeding (stage 1) in 21, nonproliferative retinopathy (stage 2) in 27, preproliferative retinopathy (stage 3) in six, proliferative retinopathy (stage 4) in 14, and proliferative retinopathy with complications (stage 5) in four. The average retinopathy stage was 1.2 +/- 1.0, mean HbA1c value 7.0 +/- 1.3%). RESULTS: The retinopathy remained unchanged in 94 patients (group A), it improved in 16 (group B), and deteriorated in 30 (group C). There was no significant change in mean HbA1c value in any of the groups (A: 6.2 +/- 0.9%; B: 6.4 +/- 1.0%; C: 6.3 +/- 6.0%). There were also no differences with respect to blood glucose, M-value according to Schlichtkrull, frequency of hypoglycaemia, serum lipids, blood pressure and renal biopsy parameters. However, significant differences (P < 0.001 C vs. A and B) were found in relation to duration of diabetes (A: 9.3 +/- 7.2 years; B: 8.8 +/- 8.6 years; C: 16.9 +/- 7.8 years) and mean retinopathy stage at beginning of the study (A: 0.8 +/- 0.8; B: 1.2 +/- 0.7; C: 2.4 +/- 1.6). CONCLUSION: Decisive for the course of retinopathy in patients with IDDM of long duration and secondarily optimised metabolic state is the duration of illness and especially the degree of fundal changes when intensified insulin treatment is undertaken.

Automated digital image analysis of organ culture preserved donor corneas.

The present study reports the application of a modified commercially available automated digital image analysis system (DIA) for the evaluation of organ culture preserved donor corneas. The central corneal endothelium was viewed and photographed under an inverted phase-contrast microscope. The images were then analyzed with the help of DIA. The results of DIA were compared to the findings obtained with a conventional 'fixed-frame analysis' for the same corneas. 100 human donor corneas have been evaluated. DIA, with interactive picture enhancement, was found to be practicable, and to yield reproducible results. The mean number of cells analyzed per photograph was 250 (range 95-395); this, on the average, was four times higher than with conventional fixed-frame analysis (mean 54, range 37-70). The correlation of the cell densities obtained with both methods was highly significant (p < 0.0001). Since additional information, like variation in cell size and shape (circularity form factor), was automatically computed by the program, more data on the homogeneity of the donor endothelial cell pattern were available. Furthermore, this computerized technique does not require an experienced investigator and thereby helps to eliminate bias.

[Retinal lymphoma--simulating uveitis]. / Retinales Lymphom--maskiert als Uveitis.

A rare form of malignant large-cell non-Hodgkin's lymphoma or reticulum cell sarcoma is confined to the eye and central nervous system (CNS). We report the case of a 62-year-old man, who presented with recalcitrant progressive uveitis in his right eye. Although lymphoma was suspected, the patient refused to undergo vitrectomy. Over one year he developed large blister-like solid scattered lesions of the retinal pigment epithelium (RPE) in the same eye. Repetitive neuroimaging detected no CNS involvement. After developing optic disc-swelling and discrete RPE-changes in the left eye also, the patient agreed to enucleation of his right eye. Histopathology and Immuno-histochemistry revealed malignant intraocular large cell-lymphoma invading all eye-tissues. Liquor cytology showed lymphomatous cells. Suffering from high grade malignant lymphoma with CNS ivolvement, the patient had to undergo radiation therapy of the orbits and neuroaxsis as well as intravenous and intrathecal chemotherapy. Papilledema of the left eye resolved quickly and completely, RPE-infiltrations disappeared and led to discrete punched out lesions with no scarring, the lens remained transparent over the whole observation period of 25 months. the patient has been surviving for more than 52 months after first suspicion of malignant lymphoma, he has retained full vision in his left eye until now.

[Taenia crassiceps in the anterior chamber of the human eye. A case report]. / Taenia crassiceps in der Vorderkammer des menschlichen Auges. Ein Fallbericht.

An otherwise healthy 15-year-old girl developed an iridocyclitis in her right eye. A contractable living parasite measuring two millimeter could be detected in the anterior chamber, the other parts of the eye remained uninvolved. The patient had close contact with the young dog of the family. By using a viscoelastic substance the parasite could be removed alive without any complications. The tapeworm was found to be too young for having developed the characteristic scolex. Western-immunoblotting gave indirect evidence for infection with Taenia crassiceps, a dog's tapeworm. During an observation period of two years no evidence for any other ocular or general Taenia crassiceps infestations could be found.

A film video processor for the viewing of fluorescein angiograms.

A new, commercially available, and inexpensive film video processor facilitates the viewing of fluorescein angiograms on video monitors. The negative film is inserted into a film carrier, read by a charge-coupled device solid state pickup device and presented as a negative or positive image on a black-and-white monitor with the help of a negative/positive conversion feature. Details of the angiogram are studied by zooming into any part of the image, which magnifies the image up to six times. Contrast and brightness adjustment on the video monitor allows examination of under- or overexposed angiograms.