Carl Erb

Absolute Rate Constants for the Quenching of Reactive Excited States by Melanin and Related 5,6-Dihydroxyindole Metabolites: Implications for Their Antioxidant Activity

Abstract The triplet-excited state of benzophenone and the singlet-excited state of 2,3-diazabicyclo[2.2.2]oct-2-ene (Fluorazophore-P) have been employed as kinetic probes to obtain information on the antioxidant activity of the skin and eye pigment melanin and its biogenetic precursors 5,6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA). The excited states were generated by the laser-flash photolysis technique and their reaction kinetics was examined by time-resolved transient absorption or fluorescence spectroscopy, respectively. The reaction between triplet benzophenone and DHI produced with unit efficiency the corresponding 6O-centered semiquinone radical, which was characterized by its characteristic transient absorption. The quenching rate constants for DHI (3.1 – 8.4 × 109 M−1 s−1) and DHICA (3.3–5.5 × 109 M−1 s−1) were near the diffusion-controlled limit, indicating excellent antioxidant properties. Kinetic solvent effects were observed. The reactivity of synthetic melanin, assessed through the quenching rate constant of Fluorazophore-P and normalized to the number of monomer units, was more than one order of magnitude lower (2.7 × 108 M−1 s−1) than that of its precursors. The trend of the quenching rate constants, i.e. DHI > DHICA ≈ α-tocopherol > melanin, along with the preferential solubility of DHICA in aqueous environments, serves to account for several experimental results from biochemical studies on the inhibition of lipid peroxidation by these natural antioxidants.

The psychology of the glaucoma patient.

Under physiological conditions, intraocular pressure (IOP) is controlled by the autonomic and central nervous systems. Correspondingly, nerve fibers and neurotransmitters are present in ciliary body and trabecular meshwork. IOP responds to physical as well as psychological stimuli in healthy individuals. In patients with dysregulated IOP, eg, in those with primary openangle glaucoma, emotional instability without a specific personality pattern could be found. Whereas the statistical association between emotional changes and glaucoma is obvious, the causal relationship remains to be clarified. It is at least plausible that psychic stress may have an influence on IOP. However, the sequence of the events is unknown (emotional disturbance can be the result of the disease or it can be a primary sign of a nervous dysfunction). Therefore, it seems meaningful-in addition to standard glaucoma therapy-to try to improve the patients emotional condition, both for treatment of the glaucoma and for the patients general quality of life.

Colour vision in normal subjects tested by the colour arrangement test ‘Roth 28-hue desaturated’

The aim of the study was to obtain normal values for the colour-arrangement test, Roth 28-hue desaturated. In 146 healthy non-smokers colour vision was tested monocularly. The subjects were divided into four age groups: 0-19, 20-39, 40-59, and 60-79 years. The overall error score for all groups was 54 +/- 24 (median +/- mean absolute deviation). The values for the 20-39 year group were significantly lower than those for the other groups (Kruskal-Wallis: P < 0.0001 with subsequent multiple Mann-Whitney test). An increasing predominance of errors along the blue-yellow-axis was observed with increasing age. The error scores of normal subjects tested by the Roth 28-hue desaturated were comparable with those on the well-known Farnsworth-Munsell 100-hue (FM-100). Because the Roth 28-hue desaturated is shorter and simpler to administer, it is an alternative to the FM-100 in situations that need to assess colour discrimination and error axis quantitatively and quickly.

White-noise field campimetry in patients with HIV infection

SummaryPurpose: The first morphological changes in eyes with HIV infection are microvascular disease of the retina with cotton-wool spots and microaneurysms. The study was performed to find out if evidence of disturbances of ocular microcirculation can be established by non-invasive methods.nPatients and methods: Twenty-seven patients with HIV infection and without opportunistic infections underwent thorough ophthalmologic examination with threshold-oriented, suprathreshold perimetry (TAP 2000 ct, Oculus) and white-noise field campimetry (TEC, Oculus).nResults: Visual field examination was normal in 23 out of 27 patients (85 %), whereas 4 patients showed relative field defects in at least one eye. In white-noise field campimetry 13 out of 23 perimetrically unaffected patients (56 %) perceived scotomas in one or both eyes. These scotomas were not stable. Three of 4 patients with relative scotomas in the visual field had cotton-wool spots in the retina and showed a stable scotoma in campimetry. Visual acuity, IOP, and cup/disc ratio were within normal ranges.nConclusion: White-noise field campimetry complements the standard examination of patients with HIV and might be capable of indicating disturbances of ocular microcirculation by a non-invasive method before morphological changes in the retina can be seen.ZusammenfassungHintergrund: Die frühesten Netzhautveränderungen bei einer HIV-Infektion sind eine Mikroangiopathie mit Cotton-wool-Herden und Mikroaneurysmen. Mit der vorliegenden Studie soll geprüft werden, ob retinale Funktionsstörungen vor morphologischen Veränderungen mit nicht invasiven Mitteln nachweisbar und eventuell als prognostische Kriterien hilfreich sind.nPatienten und Methode: 27 Patienten mit bekannter HIV-Infektion und ohne opportunistische Infektion wurden einer ophthalmologischen Untersuchung mit schwellennah überschwelliger Rasterperimetrie am Tübinger Automatik-Perimeter (TAP) und Rauschfeldkampimetrie am Tübinger Elektronik-Kampimeter (TEC) unterzogen.nErgebnisse: Im Gesichtsfeld hatten 23 von 27 Patienten (85 %) keine pathologischen Ausfälle, 4 Patienten wiesen kleine relative Ausfälle auf. Bei der Rauschfeld-Kampimetrie ließen sich bei 13 der 23 im Gesichtsfeld unauffälligen Patienten (56 %) ein flüchtiges Skotom nachweisen. Bei den 4 Patienten mit relativen Gesichtsfeldausfällen hatten 3 Patienten Cotton-wool-Herde in der Retina und feststehende, stabile Skotome. Die Sehschärfe, Augendruck und die Papillenexkavation waren im Normbereich.nSchlußfolgerung: Unsere Ergebnisse lassen eine verborgene Mikroangiopathie der Retina/Choroidea als Ursache der Skotome auch in frühen Stadien vermuten, die zum Teil auch reversibel erscheint. Die Rauschfeld-Kampimetrie scheint eine nicht invasive Methode zu sein, derartige Störungen aufzuspüren, bevor morphologische Veränderungen sichtbar werden.

Sudden increase in intraocular pressure as an initial manifestation of myelodysplastic syndrome.

PURPOSE/METHODSnWe studied a rare initial manifestation of myelodysplastic syndrome in an 82-year-old woman who had acute secondary glaucoma in the right eye and mature cataracts in both eyes.nnnRESULTS/CONCLUSIONnTherapy with glaucoma control medications and cataract extraction in the right eye resulted in expulsive hemorrhage and subsequent enucleation of the right eye. After cataract extraction, examination of the left eye disclosed a central serous retinal detachment and hemorrhage. Histopathologic analysis of the right eye demonstrated myelocytic and lymphocytic infiltration.

Funktionelle Störungen im zeitlichen Verlauf der Glaukomerkrankung

ZusammenfassungHintergrundDie glaukomatöse Optikusneuropathie ist ein komplexes Geschehen, das nicht nur zum Untergang von retinalen Ganglienzellen führt, sondern auch das 3. und 4.xa0Neuron ungünstig beeinflusst. In histologischen Studien konnte deshalb im Rahmen eines Glaukoms ein deutlicher Zellverlust sowohl im Corpus geniculatum laterale als auch im visuellen Kortex nachgewiesen werden.FragestellungDurch die Beteiligung der kompletten Sehbahn beim Glaukom kommt es zu einer Vielzahl von funktionellen Störungen, die in dieser Übersicht vorgestellt werden.ErgebnisseNeben der Entwicklung der bekannten Gesichtsfeldausfälle kommt es bei der glaukomatösen Optikusneuropathie zu Störungen beim Kontrastsehen, Farbensehen, Stereosehen und zu einer erhöhten Blendempfindlichkeit. Dadurch werden Gesichter schlechter erkannt, die Lesegeschwindigkeit ist herabgesetzt, das Auffinden von Gegenständen wird erschwert, und die Reaktionsgeschwindigkeit lässt nach. Alle diese Veränderungen nehmen mit der Progression des Glaukomschadens zu.DiskussionDie Folgen dieser visuellen Einschränkungen führen neben einer zunehmenden sozialen Isolierung zu einer steigenden Gefahr für Stürze und Autounfälle. Dadurch wird die Lebensqualität des Glaukompatienten erheblich vermindert. Deshalb soll in der Betreuung von Glaukompatienten verstärkt auf diese visuellen Schwierigkeiten hingewiesen und das häusliche Umfeld entsprechend umgestaltet werden.AbstractBackgroundGlaucomatous optic neuropathy is a complex process, which not only leads to destruction of the retinal ganglion cells but also negatively influences the third and fourth neurons. Therefore, in histological studies of glaucoma a significant cell loss in both the lateral geniculate nucleus and in the visual cortex could be detected.ObjectiveThe involvement of the entire visual pathway in glaucoma leads to a variety of functional disturbances, which are presented in this overview.ResultsBesides the well-known visual field defects in glaucomatous optic neuropathy, additional disturbances occur in contrast sensitivity, color vision, stereo vision and increased sensitivity to glare. As a result, faces are less easily recognized , the reading speed is reduced, the location of objects is more complicated and the reaction rate decreases. All these alterations are increased with the progression of glaucomatous damage.DiscussionThe consequences of these visual impairments lead to an increasing social isolation and to an increased risk of falls and driving accidents, thereby significantly reducing the quality of life of glaucoma patients. Therefore, increasing awareness of these visual difficulties is necessary in the special care of patients with glaucoma and the domestic environment should be transformed accordingly.BACKGROUNDnGlaucomatous optic neuropathy is a complex process, which not only leads to destruction of the retinal ganglion cells but also negatively influences the third and fourth neurons. Therefore, in histological studies of glaucoma a significant cell loss in both the lateral geniculate nucleus and in the visual cortex could be detected.nnnOBJECTIVEnThe involvement of the entire visual pathway in glaucoma leads to a variety of functional disturbances, which are presented in this overview.nnnRESULTSnBesides the well-known visual field defects in glaucomatous optic neuropathy, additional disturbances occur in contrast sensitivity, color vision, stereo vision and increased sensitivity to glare. As a result, faces are less easily recognized , the reading speed is reduced, the location of objects is more complicated and the reaction rate decreases. All these alterations are increased with the progression of glaucomatous damage.nnnDISCUSSIONnThe consequences of these visual impairments lead to an increasing social isolation and to an increased risk of falls and driving accidents, thereby significantly reducing the quality of life of glaucoma patients. Therefore, increasing awareness of these visual difficulties is necessary in the special care of patients with glaucoma and the domestic environment should be transformed accordingly.

Funktionelle Störungen im zeitlichen Verlauf der Glaukomerkrankung@@@Functional disorders in the chronological progression of glaucoma

ZusammenfassungHintergrundDie glaukomatöse Optikusneuropathie ist ein komplexes Geschehen, das nicht nur zum Untergang von retinalen Ganglienzellen führt, sondern auch das 3. und 4.xa0Neuron ungünstig beeinflusst. In histologischen Studien konnte deshalb im Rahmen eines Glaukoms ein deutlicher Zellverlust sowohl im Corpus geniculatum laterale als auch im visuellen Kortex nachgewiesen werden.FragestellungDurch die Beteiligung der kompletten Sehbahn beim Glaukom kommt es zu einer Vielzahl von funktionellen Störungen, die in dieser Übersicht vorgestellt werden.ErgebnisseNeben der Entwicklung der bekannten Gesichtsfeldausfälle kommt es bei der glaukomatösen Optikusneuropathie zu Störungen beim Kontrastsehen, Farbensehen, Stereosehen und zu einer erhöhten Blendempfindlichkeit. Dadurch werden Gesichter schlechter erkannt, die Lesegeschwindigkeit ist herabgesetzt, das Auffinden von Gegenständen wird erschwert, und die Reaktionsgeschwindigkeit lässt nach. Alle diese Veränderungen nehmen mit der Progression des Glaukomschadens zu.DiskussionDie Folgen dieser visuellen Einschränkungen führen neben einer zunehmenden sozialen Isolierung zu einer steigenden Gefahr für Stürze und Autounfälle. Dadurch wird die Lebensqualität des Glaukompatienten erheblich vermindert. Deshalb soll in der Betreuung von Glaukompatienten verstärkt auf diese visuellen Schwierigkeiten hingewiesen und das häusliche Umfeld entsprechend umgestaltet werden.AbstractBackgroundGlaucomatous optic neuropathy is a complex process, which not only leads to destruction of the retinal ganglion cells but also negatively influences the third and fourth neurons. Therefore, in histological studies of glaucoma a significant cell loss in both the lateral geniculate nucleus and in the visual cortex could be detected.ObjectiveThe involvement of the entire visual pathway in glaucoma leads to a variety of functional disturbances, which are presented in this overview.ResultsBesides the well-known visual field defects in glaucomatous optic neuropathy, additional disturbances occur in contrast sensitivity, color vision, stereo vision and increased sensitivity to glare. As a result, faces are less easily recognized , the reading speed is reduced, the location of objects is more complicated and the reaction rate decreases. All these alterations are increased with the progression of glaucomatous damage.DiscussionThe consequences of these visual impairments lead to an increasing social isolation and to an increased risk of falls and driving accidents, thereby significantly reducing the quality of life of glaucoma patients. Therefore, increasing awareness of these visual difficulties is necessary in the special care of patients with glaucoma and the domestic environment should be transformed accordingly.BACKGROUNDnGlaucomatous optic neuropathy is a complex process, which not only leads to destruction of the retinal ganglion cells but also negatively influences the third and fourth neurons. Therefore, in histological studies of glaucoma a significant cell loss in both the lateral geniculate nucleus and in the visual cortex could be detected.nnnOBJECTIVEnThe involvement of the entire visual pathway in glaucoma leads to a variety of functional disturbances, which are presented in this overview.nnnRESULTSnBesides the well-known visual field defects in glaucomatous optic neuropathy, additional disturbances occur in contrast sensitivity, color vision, stereo vision and increased sensitivity to glare. As a result, faces are less easily recognized , the reading speed is reduced, the location of objects is more complicated and the reaction rate decreases. All these alterations are increased with the progression of glaucomatous damage.nnnDISCUSSIONnThe consequences of these visual impairments lead to an increasing social isolation and to an increased risk of falls and driving accidents, thereby significantly reducing the quality of life of glaucoma patients. Therefore, increasing awareness of these visual difficulties is necessary in the special care of patients with glaucoma and the domestic environment should be transformed accordingly.

Comparing “suprathreshhold” and “threshhold splitting perimetry” using the Tübinger Automatic Perimeter CC

Background: We compared the standard suprathreshhold strategy to the so-called threshhold splitting strategy with 5 and 2 dB steps. The aim of the study was to establish whether the threshhold splitting strategy had advantages over the suprathreshhold strategy that has been used to date.nMethod: We examined the 30 ° visual field in 49 volunteers using suprathreshhold perimetry and on the same day threshhold splitting perimetry on the Tübinger Automatic Perimeter CC. A total of 191 test points were examined in suprathreshhold strategy. Using the threshhold splitting strategy, 67 test points were examined, with a test-point design similar to other perimeters with the threshhold splitting strategy. The criteria for inclusion in the study were central light sensitivity differences greater than 25 dB, fixation better than 80 % and an illumination class density < 2.nResults/Discussion: The average duration of the examination using the suprathreshhold strategy was 2–3 min quicker than the threshhold splitting strategy in normal visual fields or small scotomas, but it took up to 15 min longer if large scotomas were present. Interpretation of the scotoma configuration showed subjective differences: the smaller the scotoma, the greater the differences because of the fact that threshhold splitting perimetry utilizes test points that are farther apart than those used in suprathreshhold perimetry.Einleitung: Am Tübinger Automatikperimeter CC wurde eine vergleichende Studie zwischen der bekannten, schwellenorientiert überschwelligen Strategie und einer Schwellenwertstrategie mit 2 facher Eingabelung in 4- und 2-dB-Schritten durchgeführt. Ziel der Untersuchung war es, festzustellen, ob die Schwellenwertstrategie Vorteile gegenüber der bisher eingesetzten schwellenorientiert überschwelligen Strategie bietet.nMethode: 49 freiwillige Patienten wurden am gleichen Tag mit der schwellenorientiert überschwelligen Perimetrie und der Schwellenwertperimetrie am Tübinger Automatikperimeter im 30 °-Gesichtsfeld untersucht. Die Untersuchung erfolgte mit 191 Punkten bei der schwellenorientiert überschwelligen Strategie. 67 Punkte wurden bei der Schwellenwertstrategie eingesetzt, ähnlich der Prüfpunktanordnung anderer Perimeter mit Schwellenwertstrategie. Einschlußkriterien waren: zentrale Lichtunterschiedsempfindlichkeit > 25 dB, Fixation > 80 %, geprüfte Leuchtdichteklasse < − 2.nErgebnisse/Diskussion: Bei unauffälligen Gesichtsfeldbefunden oder kleinen Skotomen war die schwellenorientiert überschwellige Strategie um 2–3 min schneller als die Schwellenwertstrategie, bei großen Skotomen um bis zu 15 min langsamer. Auch in der subjektiven Prüfung der Ausfallskonfiguration fanden sich Unterschiede. Bei großflächigen Skotomen war die Erkennbarkeit der Ausfallskonfiguration für beide Strategien gegeben. Mit Abnahme der Skotomgröße führte das grobe, bei der Schwellenwertperimetrie verwendete Raster dazu, daß im Vergleich zur schwellenorientiert überschwelligen Perimetrie mit größerer Rasterdichte die Erkennbarkeit der Ausfallskonfiguration nachließ.

Latanoprost - ein neues Prostaglandin F2α-Analog in der Glaukomtherapie - eine Übersicht

An ideal glaucoma drug reduces intraocular pressure profoundly and long-lastingly without known major side effects. Latanoprost, a new prostaglandin F 2α -analogue, indeed has these properties. However, we need long-term experience to exclude major, clinically relevant side effects. The influence of latanoprost on ocular circulation also needs further evaluation. Nevertheless, the clinician does have a new and very potent drug to reduce intraocular pressure. Literature search by Medline.

P 358 White-noise field campimetry abnormalities and color vision disturbances in patients with central serous chorioretinopathy

1, Methods The DMM was designed to measure light sensitivity threshold to a white stimuli at 100 locations on a 5” region of 1” resolution at the lmacula using Humphrey Field Analyzer-640 in 24 eyes of the normal elderly. The age range was 50-69. The test of routine threshold programma 10-2 was compared. The statistical analysis was carried out for measurements. Results There were no significant difference in the DMM of the normal elderly between male and female, right and left eye, but high significant differences were found in the DMM of different eccentricity. It showed the resolving power of the DMM (5” 100 stimuli) was 4 times higher than routine K-2 programma (5” 25 stimuli). Conclusions The DMM showed high resolving power and sensitivity in macular visual function of the normal elderly. There were no significant differences between male and female, right and left eyes in the normal elderly. It was effective in determining macular visual function and