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G Rainer

Publications and source records attributed to G Rainer.

50 records · Page 3Linked to original sources
PubMed1998

Long-term course of surgically induced astigmatism after a 5.0 mm sclerocorneal valve incision.

PURPOSE: To study surgically induced astigmatism (SIA) after a sutureless 5.0 mm sclerocorneal valve incision. SETTING: Department of Ophthalmology, University of Vienna, Vienna, Austria. METHODS: This study evaluated SIA in 34 cases of sutureless cataract surgery with a 5.0 mm superior sclerocorneal valve incision and implantation of a poly(methyl methacrylate) intraocular lens. Keratometry was measured with a Zeiss keratometer in all cases preoperatively, and 1 day, 1 week, 1 and 3 months, and 1 and 5 years postoperatively. RESULTS: Surgically induced astigmatism, calculated by Cravy's vector analysis, showed an initial mean with-the-rule shift of 0.35 diopter (D), followed by an against-the-rule shift to a mean of -0.30 D after 1 month. One year postoperatively, mean SIA was -0.46 D. Between 1 and 5 years postoperatively, there was a statistically significant increase in mean SIA calculated by Cravy's vector analysis; SIA increased from -0.46 D after 1 year to -0.76 D after 5 years postoperatively. CONCLUSIONS: A small, although statistically significant, amount of postoperatively induced astigmatism occurred 5 years after a sutureless 5.0 mm sclerocorneal valve incision.

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PubMed1998

Neural activity in the primate prefrontal cortex during associative learning.

The prefrontal (PF) cortex has been implicated in the remarkable ability of primates to form and rearrange arbitrary associations rapidly. This ability was studied in two monkeys, using a task that required them to learn to make specific saccades in response to particular cues and then repeatedly reverse these responses. We found that the activity of individual PF neurons represented both the cues and the associated responses, perhaps providing a neural substrate for their association. Furthermore, during learning, neural activity conveyed the direction of the animals' impending responses progressively earlier within each successive trial. The final level of activity just before the response, however, was unaffected by learning. These results suggest a role for the PF cortex in learning arbitrary cue-response associations, an ability critical for complex behavior.

Animals↗
PubMed1998

Episcleral versus combined episcleral and intrascleral application of mitomycin-C in trabeculectomy.

BACKGROUND AND OBJECTIVE: To determine whether intrascleral exposure to mitomycin-C (MMC) improves the control of intraocular pressure (IOP), increases the incidence of complications, or both. PATIENTS AND METHODS: The authors retrospectively evaluated 38 eyes of 29 patients following the intraoperative application of MMC (0.2 mg/ml; 5 minutes). In 21 eyes the MMC-soaked sponge was applied to the intact episclera (episcleral group). In 17 eyes, two sponges, one episcleral and the other intrascleral (sandwich group), were applied. The median follow-up times were 19.0 (episcleral group) and 24.0 (sandwich group) months. Outcome measures were the IOP, the number of medications, success rates, and the incidence of complications. RESULTS: The only statistically significant difference between the two groups was the 2-week postoperative IOP, which was significantly lower in the episcleral group (P = .0314). CONCLUSION: Because there is no additional benefit, the authors recommend that the intrascleral application of MMC be avoided. However, they did not observe increased complication rates when MMC was applied in this way.

Adult↗
PubMed1997

Integration of what and where in the primate prefrontal cortex.

The visual system separates processing of an object's form and color ("what") from its spatial location ("where"). In order to direct action to objects, the identity and location of those objects must somehow be integrated. To examine whether this process occurs within the prefrontal (PF) cortex, the activity of 195 PF neurons was recorded during a task that engaged both what and where working memory. Some neurons showed either object-tuned (what) or location-tuned (where) delay activity. However, over half (52 percent, or 64/123) of the PF neurons with delay activity showed both what and where tuning. These neurons may contribute to the linking of object information with the spatial information needed to guide behavior.

Animals↗
PubMed1997

Topical anesthesia with pH-adjusted versus standard lidocaine 4% for clear corneal cataract surgery.

PURPOSE: To evaluate and compare the efficacy of a sodium-bicarbonate-adjusted preparation of lidocaine 4% (pH = 7.2) and standard lidocaine (pH = 5.2) for topical anesthesia in clear corneal cataract surgery. SETTING: Department of Ophthalmology, University of Vienna, Austria. METHODS: In a prospective, randomized, double-blind clinical trial, clear corneal cataract surgery was performed under topical anesthesia in 44 eyes of 34 patients. In 22 eyes, pH-adjusted lidocaine 4% was administered; in the other 22, standard lidocaine 4%. Aqueous and serum concentrations of lidocaine were measured by high-performance liquid chromatography and ultraviolet detection. Subjective pain was assessed using a visual analog scale of no pain (0%) to worst imaginable pain (100%). On the first postoperative day, visual acuity, intraocular pressure, and corneal staining with fluorescein were examined. RESULTS: In the pH-adjusted lidocaine group, significantly higher lidocaine concentrations were found in the aqueous humor (15.06 microg/mL +/- 8.2 [SD] versus 4.75 +/- 3.5 microg/mL; P < .0001). In all samples (n = 8), serum lidocaine concentrations were below a minimum detectable level of 0.02 microg/mL. Subjective pain ratings were similar in the pH-adjusted and standard lidocaine groups (mean 9.73 +/- 10.4% and 10.0 +/- 15.4%, respectively). There was no significant between-group difference in intraoperative and postoperative outcomes. CONCLUSIONS: In this study, pH-adjusted lidocaine 4% was a safe, effective topical anesthetic for clear corneal surgery and had minimal local and systemic toxicity. Administration of pH-adjusted lidocaine 4% resulted in significantly higher aqueous humor lidocaine concentrations than administration of standard lidocaine 4%.

Administration, Topical↗
PubMed1997

Surgically induced astigmatism following a 4.0 mm sclerocorneal valve incision.

PURPOSE: To determine whether sutureless small incision cataract surgery reduces induced astigmatism over the long term. SETTING: University Eye Hospital, Vienna, Austria. METHODS: In a prospective study, we investigated surgically induced astigmatism in 63 cases of no-stitch, small incision cataract surgery with a 4.0 mm square sclerocorneal tunnel and implantation of a flexible intraocular lens. Follow-up was 4 to 5 years. Keratometry was measured with a Zeiss keratometer preoperatively and after 1 day, 1 week, 1, 3, and 9 months, and a median of 4.4 years. In 21 nonoperated eyes, we investigated the natural course of astigmatism over 5 years. RESULTS: The mean keratometric cylinder stabilized at 0.8 diopter (D) after 1 week and slightly decreased to 1.0 D after 4 to 5 years. Cravy's vector analysis showed an immediate against-the-rule (ATR) shift of -0.2 D that remained relatively stable until 9 months. Between 9 months and 4.4 years postoperatively, there was a statistically significant increase in ATR induced astigmatism from -0.2 to -0.5 D. The natural course of astigmatism in the nonoperated eyes showed an ATR shift of -0.1 D for the same period. CONCLUSION: The result show a small, though statistically significant amount of postoperatively induced astigmatism 4 to 5 years after no-stitch, small incision cataract surgery.

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PubMed1997

[Visual acuity and use of eyeglasses after implantation of a diffractive multifocal lens].

BACKGROUND: The implantation of a diffractive multifocal lens (dMIOL) as alternative to a monofocal lens is justified if after surgery there is practically no need to wear glasses. PATIENTS AND METHODS: 31 patients had an implantation of a total of 35 dMIOLs (3M 815 LE). We evaluated the visual acuity, the refractive data and the patients' attitude to wearing glasses. The average age was 67.0 +/- 11.8 years. Follow up took place after 18.7 +/- 5.4 months. RESULTS: The mean value of the uncorrected distance acuity was 0.59 +/- 0.17 and the corrected distance acuity 0.96 +/- 0.13. The uncorrected near acuity amounted to Jg 2.40 +/- 0.94, best distance correction was Jg 1.49 +/- 0.55. The patients still accepted an average of 0.68 +/- 0.37 dpt for the best near correction (near vision over the diffractive near focus) and thus achieved Jg 1.46 +/- 0.55. At the best distance correction plus 3.5 dpt, the near visual acuity was improved to 1.03 +/- 0.17. 54.8% of the patients indicated that they did not use glasses at all. 32.3% stated that they only used glasses for reading. 9.7% wore bifocals all the time, and 3.2% always used glasses for the distance. CONCLUSIONS: Regarding distance vision, the dMIOL is equivalent to monofocal lenses. Without any correction the results of the dMIOLs for the near vision are superior to monofocal lenses. Glasses can be dispensed with if the uncorrected visual acuity of the operated eye is at least 0.6 Jg 2-3 after surgery and the other eye too, does not need any correction. In case the postoperative visual acuity is worse, good visual acuity of the other eye may render glasses unnecessary. Part of the patients put up with a correctable loss of visual acuity in order not to become dependent on glasses. The need to wear glasses may be decreased considerably by implanting a dMIOL in both eyes and by avoiding postoperative refraction errors.

Adult↗
PubMed1997

Reproducibility and sensitivity of scanning laser Doppler flowmetry during graded changes in PO2.

AIMS/BACKGROUND: Recently a commercially available scanning laser Doppler flowmeter has been produced, which provides two dimensional maps of the retinal perfusion. The aim of the present study was to investigate the reproducibility and the sensitivity of these measurements. METHODS: 16 healthy subjects were randomised to inhale different gas mixtures of oxygen and nitrogen in a double blind crossover study. The following gas mixtures of oxygen and nitrogen were administered: 100% oxygen + 0% nitrogen, 80% oxygen + 20% nitrogen, 60% oxygen + 40% nitrogen, 40% oxygen + 60% nitrogen, 30% oxygen + 70% nitrogen, 20% oxygen + 80% nitrogen, 15% oxygen + 85% nitrogen, and 10% oxygen + 90% nitrogen. Retinal haemodynamic variables and systemic haemodynamics were measured during all inhalation periods. Recordings under resting conditions were performed three times to calculate intraclass coefficients. RESULTS: In two subjects we did not obtain technically adequate results. A dose dependent change in retinal blood flow during graded oxygen breathing was observed (p < 0.001). During 100% oxygen breathing blood flow decrease was between 29% and 33%, whereas blood flow increase was between 28% and 33% during inhalation of 10% oxygen + 90% nitrogen. CONCLUSIONS: Scanning laser Doppler flowmetry has an acceptable reproducibility and is appropriate for description of the effect of graded changes in PO2 on retinal haemodynamics. The main problems with the system are the large zero offset, the fixation during retinal scanning, and the neglect of blood flow changes during the cardiac cycle.

Adult↗
PubMed1992

(H+,K+)-ATPase inhibiting 2-[(2-pyridylmethyl)sulfinyl]benzimidazoles. 4. A novel series of dimethoxypyridyl-substituted inhibitors with enhanced selectivity. The selection of pantoprazole as a clinical candidate.

[(Pyridylmethyl)sulfinyl]benzimidazoles 1 (PSBs) are a class of highly potent antisecretory (H+,K+)-ATPase inhibitors which need to be activated by acid to form their active principle, the cyclic sulfenamide 4. Selective inhibitors of the (H+,K+)-ATPase in vivo give rise to the nonselective thiophile 4 solely at low pH, thus avoiding interaction with other thiol groups in the body. The propensity to undergo the acid-catalyzed transformation is dependent on the nucleophilic/electrophilic properties of the functional groups involved in the formation of 2 since this step is both rate-determining and pH-dependent. The aim of this study was to identify compounds with high (H+,K+)-ATPase inhibitory activity in stimulated gastric glands possessing acidic pH, but low reactivity (high chemical stability) at neutral pH as reflected by in vitro (Na+,K+)-ATPase inhibitory activity. The critical influence of substituents flanking the pyridine 4-methoxy substituent present in all derivatives was carefully studied. The introduction of a 3-methoxy group gave inhibitors possessing a combination of high potency, similar to omeprazole and lansoprazole, but increased stability. As a result of these studies, compound 1a (INN pantoprazole) was selected as a candidate drug and is currently undergoing phase III clinical studies.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1981

[Synthesis and physico-chemical properties of lonazolac-Ca, a new antiphlogistic/antirheumatic agent].

Calcium-[3-(p-chlorophenyl)-1-phenylpyrazole-4]-acetate (Lonazolac-Ca, active principle of Irritren) is a new antiinflammatory/antirheumatic agent whose synthesis and physico-chemical properties are described. The physical parameters measured (pKa, partition coefficient P, saturation concentration Cs, surface activity, protein binding) are held against the corresponding values of indomethacin, diclofenac, and phenylbutazone. The size of the permeability coefficient PM of the passive transport through artificial phospholipid collodion membranes as well as the invasion curves calculated from PM indicate a good absorption of lonazolac in man.

Acetates↗
PubMedDate not supplied

Improved algorithm for statistical batch-by-batch analysis of corneal topographic data.

PURPOSE: To describe an improved algorithm for topographic batch-by-batch analysis and evaluate the effect of artifact correction on the reproducibility of topographic records. SETTING: University Eye Hospital Vienna, Austria. METHODS: We twice examined 22 eyes of 22 patients (volunteers) using the TMS-1 computer-assisted videokeratoscope (Computed Anatomy, Inc.). Entry criteria were age more than 60 years and lack of corneal pathology. A batch-by-batch analysis of the paired differences was performed. The software consisted of special macro functions for a programmable computer database to eliminate small local artifacts, as well as rotate data, produce mirror images, calculate averaged differences for an entire group, and reduce data to 225 areas in 7 concentric rings. The reduced set of data was used for statistical analysis and correction of defocus artifacts. Reproducibility was evaluated by calculating the absolute deviations between the areas of paired measurements. RESULTS: The absolute deviations were below 0.9 diopter (D) in over 50% of the areas in 90% of the patients with the uncorrected data; after correction for local artifacts, defocus artifacts, and both local and defocus artifacts, these values were 0.9 D, 0.8 D, and 0.5 D, respectively. Absolute deviations were above 1.0 D in 10% of the patients in 66, 40, 29, and 0 of 225 areas, respectively. CONCLUSION: Correction for both local and defocus artifacts yielded a two-fold improvement in the reproducibility of topographic records.

Aged↗
PubMedDate not supplied

Corneal topographic changes after frown and straight sclerocorneal incisions.

PURPOSE: To compare the corneal topographic changes following cataract surgery with two types of sclerocorneal tunnel incisions for implantation of 6.0 mm optic poly(methyl methacrylate) intraocular lenses. SETTING: University Eye Hospital, Vienna, Austria. METHODS: This prospective, unmasked, and unrandomized study comprised 48 otherwise healthy eyes scheduled for cataract surgery. A 4.5 mm sutureless frown incision was made in 22 eyes and a 6.0 mm straight sclerocorneal incision with a horizontal 10-0 nylon infinity suture in 26 eyes. Preoperatively and 1 week and 1 and 3 months postoperatively, corneal topography was recorded by the TMS-1 computer-assisted videokeratoscope (Computed Anatomy, Inc.). The data were evaluated by batch-by-batch analyses of the paired differences between the records. The significance of topographic changes was calculated by paired Wilcoxon tests; group comparisons were made using Wilcoxon tests. RESULTS: In both groups, horizontal steepening and lower corneal flattening were consistently 0.4 diopter (D). Upper peripheral corneal flattening at 1 week and 1 and 3 months postoperatively was 0.7, 0.7, and 0.7 D, respectively, in the straight-incision group and 0.7, 0.4, and 0.3 D, respectively, in the frown-incision group. Vertical flattening and horizontal steepening were significant in both groups (P < .01). Group comparisons revealed significant differences in only 15 of 225 areas (P < .05). CONCLUSION: There were no major differences between the two incision groups in surgically induced topographic changes.

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