Biomedical subjects
Publications and source records attributed to Jens Paetzold.
An efficient process for dynamic kinetic resolution of amines was developed by combining a ruthenium-catalyzed racemization with a lipase-catalyzed resolution. A variety of unfunctionalized primary amines were transformed into one enantiomer of the amide in high yield and high enantioselectivity.
The difference in threshold sensitivities that are found when examining the visual field (VF) with static versus kinetic perimetric methods is called stato-kinetic dissociation (SKD). In this pilot study, we describe a semi-automated procedure for quantifying SKD. Fifteen patients with VF defects were examined with kinetic and static perimetry. SKD values were defined as positive when the static scotoma was larger than the kinetic one. We found significant local variations of SKD along scotoma borders with the individual reaction time as an important criterion when determining kinetic thresholds. There was a verifiable SKD in all patients with locally negative values in eight subjects.
PURPOSE: To compare quantitatively visual field (VF) results obtained using a new standardized semiautomated kinetic perimetry (SKP) with those obtained by conventional Goldmann manual kinetic perimetry (MKP) in patients with advanced VF loss. DESIGN: Prospective, single-center, observational comparative case series. SUBJECTS AND METHODS: Seventy-seven eligible patients (36 suffering from advanced retinal nerve fiber layer loss, 20 with concentric constriction of the VF, and 21 with hemianopia) were included in the study. One eye of each patient was examined on the same day with MKP and SKP. Three isopters, identical in both tests, were chosen to assess the extent of the VF loss. To compare the location and size of the corresponding isopters obtained with MKP and SKP, intersection areas of superimposed isopters were expressed as a percentage of union areas. MAIN OUTCOME MEASURES: The area and position of isopters for a defined stimulus condition obtained with both methods were compared. Test duration and patients' preference were also evaluated. RESULTS: Isopters obtained with Goldmann MKP enclosed areas smaller by 20% (confidence interval [CI], 12%-27%). The mean intersection area of Goldmann and SKP VFs was 1763.1 square degrees (CI, 1558.6-1967.7) smaller than the union for stimulus III4e over all groups of patients. Semiautomated kinetic perimetry was preferred by 60% of patients with concentric constriction of the VF. Median duration of the examination was 15 minutes and did not differ significantly between the 2 methods. CONCLUSIONS: Our results indicate that SKP isopter shape and size were very comparable to those obtained on the same eyes with MKP. Semiautomated kinetic perimetry may represent a more standardized method of kinetic perimetry, which still takes advantage of perimetrist-patient interaction to diagnose and monitor advanced VF loss in clinical practice.
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PURPOSE: To quantify the area of isopters obtained using a new technique of kinetic visual field examination--semi-automated kinetic perimetry (SKP)--in case of advanced retinal nerve fiber layer (RNFL) loss, caused by glaucoma. MATERIAL AND METHODS: Forty-one subjects (19 men, 22 women; mean age 66.5 +/- 12.5 years) suffering from open-angle glaucoma (30 patients), normal tension glaucoma (5 patients), juvenile glaucoma (2 patients) and PEX glaucoma (4 patients) were examined, using SKP program implemented in Octopus 101 instrument (Haag-Streit, Koeniz, Switzerland). One eye of each patient was tested using three stimuli according to the Goldmann classification. The stimuli III4e and I4e were obligatory. Additionally one stimulus (I3e or I2e) was used depending on the character of the defect. The stimulus angular velocity was kept constant at the level of 3 degrees/s. Obtained visual field (VF) results were classified according to the Aulhorn classification into stage III (26 VF) and IV (15 VF). The areas of isopters were measured in deg2. RESULTS: The mean area of isopter III4e was 9860 deg2, I4e--5171 deg2, I3e--1093 deg2, I2e--1093 deg2 in the group of Aulhorn stage III. In the group of Aulhorn stage IV the mean area of isopter III4e was 7488 deg2, I4e--3736 deg2, I3e--1109 deg2 and I2e--818 deg2. The mean test time was 16 min. (range 9-25 min.), 15.7 min. in the group of Aulhorn stage III and 16.5 min. in the group of Aulhorn stage IV, respectively. CONCLUSION: SKP seems to be an effective method for quantitative assessment and evaluation of isopter and scotoma areas (in deg2). In this study it was demonstrated that in case of more advanced stages of glaucomatous visual field loss (Aulhorn stage IV), the areas of isopters appeared to be smaller.
PURPOSE: To compare the results of conventional suprathresold automated static perimetry (SASP) and a new method of kinetic visual field examination (semi-automated kinetic perimetry--SKP) in patients with advanced retinal nerve fibre layer (RNFL) defects, caused by glaucoma. MATERIAL AND METHODS: Nineteen patients (10 women and 9 men) suffering from advanced open-angle glaucoma (17 patients) and low tension glaucoma (2 patients) were enrolled in this study. The mean age was 65.3 years (range 49.0-82.9 years). One eye of each subject was examined with SKP and SASP, both implemented in Octopus 101 perimeter (Haag-Streit, Koeniz, Switzerland) on the same day. The examiner using SKP did not know the SASP results. The static visual field examination was performed first. In order to compare visual fields results obtained with both methods, only central 30 degree area of the visual fields was taken into consideration. The area obtained by creating a virtual isopter (option of SKP software) located between the position of defective and intact visual field regions of SASP and the area of I4e isopter obtained with SKP (stimulus angular velocity 3 degrees/s) were measured in deg2 and compared. RESULTS: The mean area (+/-SD) of I4e isopter obtained with SKP was 1882 deg2 (+/- 510 deg2) and the mean area of SASP 30 degree visual field was 1737 deg2 (+/- 546 deg2). This difference was not statistically significant. CONCLUSION: Quantitative comparison of static and kinetic perimetry is a difficult task to perform. The SKP software offers a possibility of direct quantitative assessment of the area of each isopters in deg2. This study shows that the results of visual field examinations obtained with both methods in this group do not differ significantly between SASP and SKP.
PURPOSE: To assess the applicability of a new technique of kinetic visual field examination--semi-automated kinetic perimetry (SKP)--in patients suffering from the visual field defects due to retinitis pigmentosa. METHODS: Thirty-five patients (19 women, 16 men: mean age 38.4 years) suffering from retinitis pigmentosa (10 with with Usher syndrome, one with Bardet-Biedl syndrome and one with Refsum syndrome) were examined using SKP software, implemented in Octopus 101 instrument (Haag-Streit, Koeniz, Switzerland). Three stimuli (1114e and 14e obligatory) were used to assess the hill of vision of each patient. The area of each isopter was measured in deg2. The test time was measured automatically in minutes. RESULTS: The visual field results were classified as complete or incomplete midperipheral "ring scotoma" (group I--13 patients) and concentric loss of the visual field (group II--22 patients). The area of 1114e isopter was 6147.5 deg2 in the group I and 1961.7 deg2 in the group II. The area of 14e isopter was 1468.4 deg2 and 781.7 deg2, respectively. The mean test time was 10 min. (range 4-20 min.): 8 min. in the group I and 13 min. in the group II. CONCLUSIONS: There is a large diversity of patterns of the visual field loss in retinitis pigmentosa. SKP, in contrary to widely used manual perimeter, gives a possibility of quantification of the visual field area. Future studies may be able to monitor the progression of the visual field loss caused by retinitis pigmentosa.
The manual kinetic perimetry using Goldmann instrument is still widely used and remains a "gold standard" in examining patients with any kind of advanced visual field loss and impaired co-operability. Nevertheless, Goldmann instrument has several disadvantages, such as examiner dependence, response variability, lack of standardization of parameters, poor repeatability. The latest development in kinetic perimetry, which was realized at the University Eye Hospital in Tuebingen (Germany) is semi-automated kinetic perimetry (SKP), using Octopus 101 instrument (Interzeag/Haag-Streit, Koeniz-Bern, Switzerland). It is an examiner-independent, standardized and reproducible method. Additionally, obtained results can be corrected for the mean individual reaction time. This paper will briefly present characteristic, advantages and application of SKP in clinical practice.
[reaction: see text] Alkyl-substituted vinylcarboxylates, which normally show poor enantioselectivity in Rh-catalyzed hydrogenation with traditional chiral diphosphines, undergo highly enantioselective reactions with BINOL- and carbohydrate-based monophosphite ligands.
The catalytic activity of commercially available, air and water stable ruthenium complexes in the addition of carboxylic acids to terminal alkynes was found to be drastically enhanced by the addition of small quantities of base. Moreover, the regioselectivity of the reaction can be controlled by the choice of the base so that both the Markovnikov (Na2CO3) and the anti-Markovnikov products (DMAP) are now easily accessible in excellent selectivities.
OBJECTIVE: To compare detection rates of glaucomatous visual field defects (VFDs) between the conventional 6 degrees x 6 degrees stimulus grid and locally condensed target arrangements in morphologically suspicious regions. METHODS: A total of 66 eyes of 66 patients with glaucoma or patients suspected of having glaucoma (34 females and 32 males; age range, 14-85 years) were enrolled in this study. Individual, local target condensation was realized by fundus-oriented perimetry (FOP) using a campimeter and compared with the results of conventional automated perimetry (CAP), obtained with the Humphrey Field Analyzer (30-2 grid). RESULTS: Twenty-three of the 66 patients showed normal findings with both methods; 27 had concordantly pathological results. In 15 patients we obtained normal findings with CAP, whereas FOP revealed early glaucomatous VFDs. Only one patient showed VFDs with CAP, whereas FOP results were normal. Scotoma detection rates significantly differed between the 2 methods (P<.001, sign test). Test duration with FOP was more than doubled compared with CAP. When considering only FOP points coinciding with the 6 degrees spacing of the 30-2 grid, there was no longer a significant difference between FOP and CAP (P>.25, sign test). This indicated that the target pattern, rather than the perimetric device, was most relevant for detecting glaucomatous VFDs. Follow-up throughout a series of 3 subsequent sessions at 6-month intervals revealed repeatable results in more than two thirds of all eyes for both FOP and CAP. CONCLUSIONS: Fundus-oriented perimetry that uses individually condensed test grids significantly increases the detection rate of glaucomatous VFDs in morphologically conspicuous areas compared with CAP using equidistant (6 degrees x 6 degrees) target arrangements. Repeatability is comparable between both methods.