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C Erb

Publications and source records attributed to C Erb.

At least 37 records · Page 2Linked to original sources
PubMed2001

Modulation of Na/K-ATPase activity by isoproterenol and propranolol in human non-pigmented ciliary epithelial cells.

PURPOSE: The present study investigates whether beta-adrenoreceptor agents such as isoproterenol and propranolol can regulate Na(+)-K(+)-ATPase activity in cultured human non-pigmented ciliary epithelial cells. METHODS: Human non-pigmented ciliary epithelial cells (ODM2) were grown to confluence. The active ion transport mediated by the Na(+)-K(+)-ATPase was evaluated by measuring ouabain-sensitive rubidium (Rb+) uptake. In a first set of experiments, cells were exposed to the beta-adrenoreceptor agonist isoproterenol (0.01-10 microM). In a second set of experiments, cells were exposed to isoproterenol (1 microM) in the presence of different concentrations of the beta-adrenoreceptor antagonist propranolol (0.01, 0.1, 1 microM). RESULTS: In a concentration-dependent manner, isoproterenol induced an increase in Na(+)-K(+)-ATPase activity. The maximal Na(+)-K(+)-ATPase activity was observed at a concentration of 1 microM of isoproterenol (283 +/- 58%, P < 0.001). The increase in Na(+)-K(+)-ATPase activity evoked by isoproterenol (1 microM) was inhibited. In a concentration dependent manner, by propranolol (maximum: 659 +/- 39 vs. 141 +/- 42 pM/mg protein/min, P < 0.01). CONCLUSION: The beta-adrenoreceptor agents isoproterenol and propranolol are apparently able to modulate Na(+)-K(+)-ATPase activity in cultured human non-pigmented ciliary epithelial cells.

Adrenergic beta-Agonists↗
PubMed2001

Energy-filtering transmission electron microscopy (EFTEM) in the elemental analysis of pseudoexfoliative material.

PURPOSE: To obtain more information on the basic nature of the pathological matrix product accumulating in pseudoexfoliation (PEX) syndrome by analyzing its elemental composition at the subcellular level. METHODS: Energy-filtering transmission electron microscopy (EFTEM), combining the two microanalytical techniques of electron spectroscopic imaging (ESI) and energy-loss spectroscopy (EELS), were performed on ultrathin sections of lens specimens with PEX syndrome using a transmission electron microscope equipped with an integrated electron energy filter. EFTEM is based on inner shell ionization of elements present in the sample giving rise to characteristic signals in well-defined energy-loss regions. The EEL-spectra, demonstrating the presence of a particular element by its specific electron energy-loss edge, were recorded with an integrated scintillator-photomultiplier-system. ESI generated graphic images of elemental localization in the sections after a process of background correction with an IBAS image analysis program. Energy-dispersive X-ray (EDX) analysis of PEX deposits on hydrated lenses was conducted by variable pressure scanning electron microscopy. RESULTS: The ESI element distribution images of both intracapsular and supracapsular PEX material displayed high signals for nitrogen, sulfur, calcium, chlorine, and zinc in clear association with the PEX fibrils. The corresponding EEL-spectra confirmed the data obtained by ESI and showed the presence of the element-specific energy-loss edges. The presence of these elements in PEX fibrils was further confirmed by EDX analysis. No specific signals were obtained for phosphorus, oxygen, or aluminum. CONCLUSIONS: This study demonstrates the presence of nitrogen, sulfur, chlorine, zinc, and calcium both in mature and in aggregating PEX fibrils of the lens capsule. EFTEM proved to be a highly sensitive method for the microanalytical study of biological material with unknown composition, such as PEX material, at the subcellular level.

Calcium↗
PubMed2001

Expression of the melanin-concentrating hormone receptor in porcine and human ciliary epithelial cells.

PURPOSE: To evaluate whether the receptors for melanin-concentrating hormone (MCH) and its functional antagonist alpha-melanocyte-stimulating hormone (alpha-MSH) are expressed in the ciliary epithelium. Furthermore, to examine whether MCH, a neuropeptide involved in fluid and electrolyte homeostasis, may influence ion flux mediated by Na,K (adenosine triphosphatase)-ATPase in a ciliary epithelial cell line. METHODS: Expression of MCH receptors (MCH-R) and alpha-MSH receptors (MSH-R) on primary porcine ciliary pigmented epithelial (PE) cells and on a human nonpigmented ciliary epithelial (NPE) cell line, ODM-2 was investigated by radioligand binding studies and reverse transcription-polymerase chain reaction (RT-PCR). The MCH-R was further characterized by photocrosslinking. Influence of MCH on Na, K-ATPase activity was evaluated by an Rb(+) transport assay. RESULTS: MCH-R expression was observed at both the mRNA and protein levels in PE and NPE cells. In contrast, MSH-Rs were not detectable. At the mRNA level, expression of slc-1 was shown and with crosslinking, a 44-kDa protein was labeled. MCH showed no effect on Na,K-ATPase activity of NPE cells. CONCLUSIONS: The presence of MCH-R in ciliary epithelial cells of both human and porcine origin but the absence of MSH-Rs indicates that in these cells, MCH and alpha-MSH do not form a functionally antagonistic hormonal pair as they do in several other systems. Although effects of MCH on intestinal water and ion transport have been documented, a direct control of Na,K-ATPase activity was not detected in human NPE cells in vitro.

Animals↗
PubMed2000

Choroidal laser Doppler flowmetry in healthy subjects.

OBJECTIVE: To evaluate normal choroidal blood flow and its relationship with various factors such as age, systemic blood pressure, and intraocular pressure (IOP). METHODS: A total of 70 healthy subjects were recruited. Choroidal blood flow was assessed using a method based on laser Doppler flowmetry (LDF) technique. The LDF parameters of velocity, volume, and flux were obtained. The influence of age, mean systemic blood pressure, IOP, smoking, and sex on choroidal hemodynamic parameters was assessed in a multiple linear regression model. The correlations between interocular difference in IOP and interocular differences in the LDF parameters were assessed by means of the Pearson linear correlation factor. RESULTS: Velocity decreased significantly (P = .03) with advancing age of the subjects and volume increased significantly (P = .02) with increasing IOP. Mean blood pressure, smoking, and sex had no influence on the choroidal LDF parameters. Interocular difference in IOP correlated significantly with interocular difference in volume (R = 0.34, P<.005). CONCLUSION: Choroidal blood flow velocity decreased with increasing age of the subjects, while the volume of moving erythrocytes decreased with lower IOP.

Adolescent↗
PubMed2000

[Evaluating the Pro Ton applanation tonometer in rabbits].

PURPOSE: To assess use of the tonometer ProTon for measuring intraocular pressure in rabbits. MATERIALS AND METHODS: Eleven chinchilla-bastard rabbits were measured under standardized conditions with the applanation tonometer ProTon for 62 +/- 15 days. One rabbit was excluded because of intensively defensive reactions. RESULTS: Intraocular pressure in the ten rabbits was 12.15 +/- 3.63 mmHg in the right eye and 12.11 +/- 3.52 mmHg in the left eye. CONCLUSION: Intraocular pressure can be measured reliably over a long period with the applanation tonometer ProTon. It is therefore suitable for determining intraocular pressure in experimentally induced glaucoma in rabbits.

Animals↗
PubMed2000

[Noise field findings in 24 patients with coronary heart disease].

PURPOSE: In earlier studies it was shown that patients with vascular disturbances (e.g. sudden hearing loss) had white-noise field campimetry abnormalities despite normal visual fields. The aim of this study was to clarify whether patients with coronary heart disease (CHD) have such disturbances in the white-noise field campimetry, too. PATIENTS AND METHODS: Twenty-four patients (m:f = 23:1; mean age 58 +/- 9 years) with an angiographically documented CHD and 30 healthy controls (m:f = 29:1; mean age 54 +/- 7 years) were examined. In order to evaluate the morphological and functional ocular status, we examined the following parameters: morphological status, visual acuity, intraocular pressure, perimetry (Tübinger Automatic Perimeter 2000 ct, Oculus) and white-noise field campimetry (Tübinger Electronic Campimeter, Oculus). RESULTS: Fifteen patients had had a cardiac infarction. Twenty-one patients, but only 6 controls had alterations in perilimbal vessels of the conjunctiva and sixteen patients had a tortuousity of retinal vessels. The visual acuity, the intraocular pressure, the cup/disc ratio and the visual fields were within normal ranges. However, twenty patients and 5 controls were abnormal in the white-noise field campimetry. DISCUSSION: Although patients with CHD appeared unaffected in the standard eye examinations, the disturbances in the white-noise field campimetry indicated a functional visual impairment. Together with the changes in the perilimbal vessels of the conjunctiva and the retinal vessels, a disturbed ocular microcirculation as the underlaying cause could be discussed.

Adult↗
PubMed2000

[Manifestation of Creutzfeldt-Jakob disease 30 years after corneal transplantation].

BACKGROUND: Creutzfeldt-Jakob disease, currently viewed as one of the prionic diseases, occurs in by far the majority of cases sporadically, sometimes in families, and in rare instances as a transmissible disease with every conceivable interval of latency. HISTORY AND SIGNS: This report of a 45-year-old female concerns a spongiform encephalopathy which appeared almost 30 years after penetrating keratoplasty. The corneal material came from a 63-year-old donor with Creutzfeldt-Jakob disease; the keratoplasty was performed at a time when the transmissibility of certain diseases was still unknown. CONCLUSION: The risk of transmission of the disease is very low but cannot be ruled out.

Creutzfeldt-Jakob Syndrome↗
PubMed2000

Absolute rate constants for the quenching of reactive excited states by melanin and related 5,6-dihydroxyindole metabolites: implications for their antioxidant activity.

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 x 10(9) M-1 s-1) and DHICA (3.3-5.5 x 10(9) 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 x 10(8) M-1 s-1) than that of its precursors. The trend of the quenching rate constants, i.e. DHI > DHICA approximately alpha-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.

Antioxidants↗
PubMed1999

Formation of N-methylnicotinamide in the brain from a dihydropyridine-type prodrug: effect on brain choline.

The enhancement of brain choline levels is a possible therapeutic option in neurodegenerative diseases; however, brain choline levels are held within narrow limits by homeostatic mechanisms including the rapid clearance of excess choline from the brain. The present study tests whether N-methylnicotinamide (NMN), an inhibitor of the outward transport of choline from the brain, can elevate brain choline levels in vivo. As NMN does not cross the blood-brain barrier, we synthesized and administered the brain-permeable prodrug, 1,4-dihydro-N-methyl-nicotinamide (DNMN), and tested its effect on the levels of NMN and choline in brain extracellular fluid, using the microdialysis procedure. Administration of DNMN (1 mmol/kg s.c.) caused a 4- and 9-fold increase in plasma and liver NMN levels, respectively, as determined by HPLC. Concomitantly, the brain tissue levels of NMN were increased by a factor of twenty. In brain extracellular fluid, the injection of DNMN (1-3 mmol/kg s.c.) elevated NMN levels by 3- to 10-fold to maximum levels of >10 microM. In spite of these enhanced NMN levels, the choline concentrations in the brain extracellular fluid and in the cerebrospinal fluid (4.7 microM) remained unchanged or were even slightly decreased. Microsomal incubations of DNMN indicated that cytochrome P-450 3A isoforms may be involved in NMN formation in the liver, but not in the brain. We conclude that DNMN, a brain-permeable prodrug of NMN, is efficiently oxidized to NMN in the brain, but a 10-fold increase in extracellular NMN levels is not sufficient to reduce the clearance of choline from the brain.

Animals↗
PubMed1999

Relationship between corneal temperature and finger temperature.

BACKGROUND: Because the temperature of the body surface depends largely on local blood flow, temperature measurements might provide information on the latter. OBJECTIVE: To evaluate the relationship between corneal temperature and finger temperature. METHODS: Corneal, finger, and body core temperatures were measured in a relatively unselected population of 266 white persons. Excluded were persons taking topical eye medication or with corneal inflammatory signs. Corneal and finger temperatures were measured on 1 randomly selected side of the body by means of a noncontact infrared thermometer. As a measure of body temperature, the tympanic temperature was measured by means of a noncontact infrared ear thermometer. A total of 124 females and 142 males were examined. RESULTS: A correlation analysis in a least squares regression model was highly significant (R = 0.67; P<.001), with corneal temperature as the dependent variable and environmental, tympanic, and finger temperatures and age and sex as predicting variables. All variables contributed significantly to prediction of the corneal temperature. The corrected mean corneal temperature after adjusting for environmental, tympanic, and finger temperatures and for age of participants was 0.16 degrees C higher in male participants (P = .002). CONCLUSIONS: Corneal temperature correlates with finger temperature even after adjusting for environmental and tympanic temperatures and for the age and sex of participants. A possible cause for these findings are some parallelisms in blood-flow regulation in the finger and the eye.

Adolescent↗
PubMed1999

[White-noise field campimetry in HIV+ patients].

PURPOSE: 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. PATIENTS 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). RESULTS: 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. CONCLUSION: 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.

Adult↗
PubMed1999

Colour vision disturbances in chronic smokers.

PURPOSE: The aim of the present study was to test the influence of smoking on colour perception. SUBJECTS AND METHODS: At the University Eye Hospital Tübingen, 76 generally healthy smokers with inconspicuous ophthalmological findings (visual acuity, refraction, intraocular pressure, morphology) were examined by the cap-sorting test, Roth 28-hue desaturated. Group 1 was comprised of smokers (n = 20; M 9, F 11; mean age 28.1+/-10.3 years) with a smoking consumption of less than one packet of cigarettes per day (8.4+/-5.3 cigarettes/day) for 9.1+/-8.3 years. Group 2 consisted of smokers (n = 32; M 22, F 10; mean age 28.6+/-9.7 years) with a smoking consumption of one or more than one packet per day (30+/-8.4 cigarettes/ day) for 9.5+/-8.3 years. Generally healthy and ophthalmologically normal non-smokers served as a control group (n = 76; M 41, F 35; mean age 30+/-9 years). RESULTS: The average error score of the control group was (median +/- mean absolute deviation) 42+/-18. Group 1 showed no difference to the control group (51+/-27; P = 0.42). On the other hand, group 2 had a significantly higher error score than the control group (102+/-45; P<0.0001). CONCLUSION: Otherwise healthy smokers with a cigarette consumption of less than 20 cigarettes per day do not show any disturbances in colour vision. Smokers who consume more than 20 cigarettes per day may suffer colour vision defects as a result.

Adult↗
PubMed1999

Psychological characteristics of patients with normal-tension glaucoma.

BACKGROUND: A study was carried out to evaluate the extent of psychosomatic complaints in patients with normal-tension glaucoma. METHODS: Twenty-four patients (M:F=3:21; mean age 58+/-15.3 years) with normal-tension glaucoma were rated according to the von Zerssen Symptom List (psychosomatic discomfort), the Maudsley Personality Inventory (MPI-N, emotional status and MPI-E, extroverted-introverted), the Beck Depression Inventory (BDI), and the Sixteen Personality Factor Questionnaire (16PF). An age- and sex-matched control group (n=24; M:F=3:21; mean age 56+/-13 years) without any ocular or other general chronic disease was selected. RESULTS: In comparison with the control group the patients with normal-tension glaucoma showed significantly more complaints (von Zerssen Symptom List) and were more emotionally unstable (MPI-N). No group differences were found regarding extroversion-introversion (MPI-E) and depression (BDI). In the 16PF, patients with normal-tension glaucoma were remarkable, only for a significant negative correlation between the duration of illness and psychic endurance. CONCLUSION: The results demonstrate that patients with normal-tension glaucoma show evident psychosomatic involvement. However, the sequence of the pathogenetic development remains unclear. Therefore, it is not known whether these psychological disturbances are factors contributing to the development of normal-tension glaucoma or whether they are a result of normal-tension glaucoma. Nevertheless, some patients with normal-tension glaucoma had these disturbances. Besides reduction of intraocular pressure and improvement of vascular condition, those who display psychological disturbances should receive psychological support, such as autogenic training.

Adult↗
PubMed1999

Intraocular pressure changes: the influence of psychological stress and the Valsalva maneuver.

The effects of psychological stress and the Valsalva maneuver on short-term variations of intraocular pressure (IOP) were studied in 49 healthy adults. Psychological stress consisted of mental arithmetic tasks presented in counterbalanced order by computer and by the experimenter. Additionally, a standardized Valsalva maneuver was performed (in counterbalanced order with the psychological stressors). IOP was measured with a Goldmann tonometer before and after performance of each stressor. All three stressors transiently and highly significantly increased IOP, although the Valsalva maneuver produced changes of a greater magnitude (10.2 mmHg) than the psychological stressors (1.3 mmHg). Subjective stress ratings and heart rate increased in response to all stressors. There were no effects of task sequence, eye muscle tension, sex, smoking status (some smokers misreported their smoking status), or regular marijuana use, but regular physical exercise was associated with less IOP increase during psychological stress.

Adult↗
PubMed1999

[Dermatitis and conjunctivitis after contact with Euphorbia myrsinites (wolf's milk extract)--a case report].

BACKGROUND: Fresh sap of euphorbiaceae leads to a toxic burn of the skin and the eyes. Since years the sap of euphorbiaceae has been used in the treatment of different kinds of verrucas. PATIENTS: After contact with the sap of Euphorbia myrsinites three children developed a toxic dermatitis. In addition, the youngest girl showed a conjunctivitis and an occlusion of the right eye. Phorbolesters are considered to be responsible for the toxicity of the euphorbiaceae. All three children have resulted in a restitutio ad integrum. CONCLUSION: This case report is demonstrating the danger of toxic burn of this kind of plant.

Administration, Topical↗
PubMed1999

[Cyclocryocoagulation in treatment of therapy refractory glaucoma: a retrospective analysis of 185 cryocoagulation procedures].

BACKGROUND: For several years it has been discussed whether cyclocryotherapy is still an up-to-date treatment of resistant inadequately controlled glaucoma. This retrospective study investigates the clinical aspects of 185 cyclocryotherapies between 1988 and 1997. PATIENTS AND METHODS: At the University Eye Clinic of Tübingen, 114 patients received in 119 eyes (64.3%) one cyclocryotherapy, and in 66 eyes (35.7%) multiple cyclocryotherapies. The standard surgical techniques for cyclocryotherapy can be summarized as followed: probe placements per eye, 4 to 6; location of probe placement, inferior circumference (63.9%); distance of the applicator from limbus, 3 mm (50.7%); temperature of the probe tip, -70 degrees C (34.2%); and time of the treatment, 60 seconds (89.9%). RESULTS: Intraocular pressure was on average 33.8 mm Hg before treatment. In all analysed glaucoma types intraocular pressure was lowered to 10.2 mm Hg (30%). The most frequent type of glaucoma was the neovascular glaucoma (55%). One year after treatment, this type showed on average, relative to all other types of glaucoma, the highest intraocular pressure (28.1 mm Hg) and a lowering of intraocular pressure by 8.3 mm Hg (22.7%). Half a year after cyclocryotherapy, a highly significant (p < 0.002) reduction of antiglaucomatous medication was achieved in comparison to the preoperative medication. CONCLUSION: Despite the fact that cyclocryotherapy is not always effective, it is an ambulant surgical technique easy to apply, non-invasive, cost-effective and can be repeated to lower intraocular pressure in resistant chronic glaucoma. We conclude that cyclocryotherapy will remain useful until new techniques, like the diode laser cyclophototherapy (especially ultrasonic controlled), are developed as alternative therapies.

Adult↗
PubMed1998

Enhancement of brain choline levels by nicotinamide: mechanism of action.

Following the subcutaneous (s.c.) administration of nicotinamide (10 mmol/kg), the brain and CSF levels of nicotinamide were increased to millimolar concentrations, but the concentrations of N-methylnicotinamide (NMN) in the CSF, and of NMN and NAD+ in brain tissue were not significantly altered. Concomitantly, nicotinamide caused increases of the choline levels in the venous brain blood. In hippocampal slices, nicotinamide (1-10 mM) induced choline release in a calcium- and mepacrine-sensitive manner and, in [3H]choline-labelled slices, increased the levels of [3H]lyso-phosphatidylcholine and [3H]glycerophosphocholine. We conclude that nicotinamide enhances brain choline concentrations by mobilising choline from choline-containing phospholipids, presumably via activation of phospholipase A2, while the formation of NMN does not contribute to this effect.

Animals↗