13 results on '"Maag KP"'
Search Results
2. Pentosan Polysulfate Inhibits Attachment and Infection by SARS-CoV-2 In Vitro: Insights into Structural Requirements for Binding.
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Bertini S, Alekseeva A, Elli S, Pagani I, Zanzoni S, Eisele G, Krishnan R, Maag KP, Reiter C, Lenhart D, Gruber R, Yates EA, Vicenzi E, Naggi A, Bisio A, and Guerrini M
- Subjects
- Animals, Anticoagulants pharmacology, Chlorocebus aethiops, Heparin therapeutic use, Protein Binding, Spike Glycoprotein, Coronavirus, Vero Cells, Pentosan Sulfuric Polyester pharmacology, SARS-CoV-2 drug effects, Virus Attachment drug effects
- Abstract
Two years since the outbreak of the novel coronavirus SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) pandemic, there remain few clinically effective drugs to complement vaccines. One is the anticoagulant, heparin, which in 2004 was found able to inhibit invasion of SARS-CoV (CoV-1) and which has been employed during the current pandemic to prevent thromboembolic complications and moderate potentially damaging inflammation. Heparin has also been shown experimentally to inhibit SARS-CoV-2 attachment and infection in susceptible cells. At high therapeutic doses however, heparin increases the risk of bleeding and prolonged use can cause heparin-induced thrombocytopenia, a serious side effect. One alternative, with structural similarities to heparin, is the plant-derived, semi-synthetic polysaccharide, pentosan polysulfate (PPS). PPS is an established drug for the oral treatment of interstitial cystitis, is well-tolerated, and exhibits weaker anticoagulant effects than heparin. In an established Vero cell model, PPS and its fractions of varying molecular weights inhibited invasion by SARS-CoV-2. Intact PPS and its size-defined fractions were characterized by molecular weight distribution and chemical structure using nuclear magnetic resonance spectroscopy and liquid chromatography-mass spectrometry, then employed to explore the structural basis of interactions with SARS-CoV-2 spike protein receptor-binding domain (S1 RBD) and the inhibition of Vero cell invasion. PPS was as effective as unfractionated heparin, but more effective in inhibiting cell infection than low-molecular-weight heparin (on a weight/volume basis). Isothermal titration calorimetry and viral plaque-forming assays demonstrated size-dependent binding to S1 RBD and inhibition of Vero cell invasion, suggesting the potential application of PPS as a novel inhibitor of SARS-CoV-2 infection., Competing Interests: None declared., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)
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- 2022
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3. Efficacy of pentosan polysulfate for the treatment of interstitial cystitis/bladder pain syndrome: results of a systematic review of randomized controlled trials.
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van Ophoven A, Vonde K, Koch W, Auerbach G, and Maag KP
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- Humans, Randomized Controlled Trials as Topic, Cystitis, Interstitial drug therapy, Pentosan Sulfuric Polyester therapeutic use
- Abstract
Background: Among the numerous therapeutic approaches used in the treatment of interstitial cystitis/bladder pain syndrome (IC/BPS) few have been assessed with a sufficient level of evidence. The safety and efficacy of pentosan polysulfate sodium (PPS) has been shown in several open-label and comparative clinical trials with different populations including two meta-analyses. In the context of the approval procedure of PPS for the treatment of IC/BPS by the European Medicines Agency we updated the findings of the previous analyses by incorporating the results of the latest studies. Method: Relevant studies based on a systematic review of PubMed/Medline and the Cochrane Library in June 2018 were identified. For completeness control, clinical trial registries were also searched. Only randomized, placebo-controlled clinical trials providing sufficient information to estimate at least one relevant effect size measure to compare the efficacy of PPS versus placebo were included in the analysis. Results: Of the studies identified in the literature search, six randomized placebo-controlled studies met the pre-defined eligibility criteria. Analyses showed no indication of heterogeneity or publication bias. Treatment with PPS led to a statistically significant improvement in the patient's overall response assessment ( p < .001), pain ( p = .009) and urgency ( p = .005). Conclusions: Our meta-analyses confirmed the results of preceding meta-analyses showing that PPS is efficacious compared to placebo in the treatment of bladder pain, urinary urgency and frequency of micturition and thus an evident option for the treatment of IC/BPS symptoms.
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- 2019
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4. Detection of optic neuropathy in glaucomatous eyes with normal standard visual fields using a test battery of short-wavelength automated perimetry and pattern electroretinography.
- Author
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Bayer AU, Maag KP, and Erb C
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- Female, Humans, Intraocular Pressure, Male, Middle Aged, Pattern Recognition, Visual, Prospective Studies, Vision Disorders diagnosis, Visual Acuity, Electroretinography methods, Glaucoma, Open-Angle diagnosis, Optic Disk pathology, Optic Nerve Diseases diagnosis, Visual Field Tests methods, Visual Fields
- Abstract
Purpose: To evaluate the clinical use of a test battery of short-wavelength automated perimetry (SWAP), frequency-doubling technology (FDT) perimetry, and pattern-electroretinography (PERG) in patients with definite primary open-angle glaucoma (POAG) but normal results on standard automated perimetry (SAP)., Study Design: Prospective, comparative, observational case series., Participants: Thirty-six patients with POAG with standard visual field defects in one eye and normal standard visual fields in the contralateral eye and 36 normal controls were enrolled., Main Outcome Measures: SWAP, PERG, FDT, and SAP were performed in all eyes, and global indices and amplitudes were used for statistical analysis., Results: When contralateral POAG eyes with asymmetric glaucomatous damage was compared, a paired t test showed significant differences in SAP mean deviation (MD) (P < 0.0001), SWAP-MD (P = 0.0003), FDT-MD (P = 0.0008), and PERG amplitudes (P < 0.0001). When comparing between POAG eyes with normal results on SAP and normal controls, Student's t test showed significant differences for SWAP-MD (P < 0.0001), FDT-MD (P = 0.0006), PERG N1P1-amplitude (P = 0.0486) and P1N2-amplitude (P < 0.0001); receiver operating characteristic analysis revealed promising accuracy for SWAP-MD of 73.6% (P < 0.0001). SWAP-MD (P < 0.0001) and FDT-MD (P < 0.0001) correlated significantly with SAP-MD and with each other (range, P < 0.0001 to P = 0.0020). Regression analysis revealed that PERG P1N2-amplitude could improve the power of SWAP-MD from 73.6% to detect early POAG in eyes with normal results on SAP to an accuracy of 81.9%., Conclusions: A test battery of SWAP-MD and PERG P1N2-amplitude could detect glaucomatous optic neuropathy in POAG eyes with normal standard visual fields, whereas FDT-MD and SWAP-MD significantly correlated with each other and with SAP-MD. All tests were able to detect the eye with the more severe glaucomatous optic neuropathy in patients with asymmetric POAG.
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- 2002
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5. Association of glaucoma with neurodegenerative diseases with apoptotic cell death: Alzheimer's disease and Parkinson's disease.
- Author
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Bayer AU, Keller ON, Ferrari F, and Maag KP
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- Aged, Alzheimer Disease diagnosis, Female, Glaucoma, Open-Angle diagnosis, Humans, Intraocular Pressure, Male, Optic Disk pathology, Parkinson Disease diagnosis, Prevalence, Retrospective Studies, Risk Factors, Vision Disorders complications, Visual Fields, Alzheimer Disease complications, Apoptosis, Glaucoma, Open-Angle complications, Parkinson Disease complications
- Abstract
Purpose: To report a possible association of glaucoma with Parkinson's disease and Alzheimer's disease., Methods: Retrospective chart review (observational case series). The ophthalmologic charts of 49 patients with Alzheimer's disease and of 38 patients with Parkinson's disease were reviewed to determine the occurrence rate of glaucoma among these patients., Results: Glaucomatous visual field defects or cup-to-disk ratios of 0.8 or greater were recorded in 12 patients with Alzheimer's disease (24.5%) and in 9 patients with Parkinson's disease (23.7%)., Conclusion: Patients with Alzheimer's disease and Parkinson's disease may have an increased occurrence rate of glaucoma.
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- 2002
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6. Evaluation of different recording parameters to establish a standard for flash electroretinography in rodents.
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Bayer AU, Cook P, Brodie SE, Maag KP, and Mittag T
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- Analysis of Variance, Animals, Contact Lenses, Corneal Injuries, Dark Adaptation, Electroretinography adverse effects, Electroretinography methods, Female, Gold, Mice, Mice, Inbred C57BL, Rats, Rats, Wistar, Electroretinography standards, Microelectrodes adverse effects, Photic Stimulation methods, Retina physiology
- Abstract
Different electrodes and stimulus protocols commonly used for electroretinography in rodent eyes were compared for convenience of use, degree of damage to corneal epithelium, and for magnitude of amplitude, reproducibility, left versus right eye accuracy, and reliability of recorded parameters of the flash electroretinogram (ERG). Adult C57BL/6 pigmented mice and albino Wistar rats were used to determine scotopic ERGs in response to Ganzfeld or strobe-light stimulation and light-adapted (photopic) ERGs recorded from both eyes at the same time. Test-retest data were used for statistical analyses to compare a monopolar gold-wire contact lens electrode (CLE), a cotton-wick silver-silver chloride electrode (CSCE), a DTL fiber electrode (DTLE), and a circular stainless steel wire electrode (SSE). Corneas were evaluated for abrasion after ERG recordings using fluorescein staining and also for the time taken, ease of insertion, and re-insertions required for the different electrodes. Compared to CSCE, DTLE, and SSE, the ERG potentials recorded by CLE had significantly larger scotopic amplitudes and oscillatory potentials under strobe or Ganzfeld stimulation and for light-adapted ERG b-wave amplitudes in both mice and rats. In analyzing test-retest data of scotopic ERG a-wave and b-wave amplitudes, the intraclass correlation coefficient showed the best agreement for the CLE (range 0.61-0.94) compared to the SSE (0.13-0.77), DTLE (0.02-0.69), and CSCE (0.12-0.51). In mice and rats, logistic regression analyses revealed significant correlations for amplitudes of most scotopic ERG parameters between contralateral eyes obtained with CLE and for some ERG components recorded by SSE. When comparing ERG amplitudes for stimulation by strobe or Ganzfeld, the difference was least with the CLE compared to DTLE, CSCE, or SSE. The time taken to insert the four different electrodes was greatest for the CLE in both mice and rats. The extent of corneal abrasion resulting from electrode use in mice was largest for the SSE followed by the CLE. However, in rats there was almost no corneal damage after ERG recordings with the CLE. Because of the stability of eye contact, the CLE allows ERGs to be determined over a longer recording session. Recording of scotopic and photopic (light-adapted) ERGs in rodents with monopolar gold-wire contact lens electrodes provides greater amplitudes and higher reproducibility when compared to other commonly used corneal electrodes. These electrodes are significantly better overall than others that were evaluated and should be considered for a standard protocol to monitor retinal function in rodent eyes.
- Published
- 2001
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7. Electroretinographic abnormalities in a rat glaucoma model with chronic elevated intraocular pressure.
- Author
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Bayer AU, Danias J, Brodie S, Maag KP, Chen B, Shen F, Podos SM, and Mittag TW
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- Adaptation, Ocular physiology, Analysis of Variance, Animals, Disease Progression, Electroretinography methods, Female, Fourier Analysis, Linear Models, Logistic Models, Normal Distribution, ROC Curve, Rats, Rats, Wistar, Sensitivity and Specificity, Time Factors, Glaucoma, Open-Angle physiopathology
- Abstract
The purpose of this study was to determine the ability of electroretinographic (ERG) measurements to document progression of the retinopathy in a rat glaucoma model. Thirty four rats with a chronic intraocular pressure (IOP) elevation induced in one eye by cautery of three episcleral/extra-orbital veins were studied in four separate groups. ERGs were recorded sequentially in Group A rats (n = 12) at baseline, and after approximately 20, 40 and 60 days of high IOP, and in three additional groups of rats (n = 6 or 10 per group) after approximately 58, 30 and 175 days of high IOP, respectively. Scotopic ERG parameters recorded simultaneously from both eyes in Group A rats were: a- and b-wave amplitudes, implicit times, oscillatory potential amplitudes (OPs) determined at three different light-flash intensities, and the light-adapted (photopic) ERG b-wave amplitude. In the other groups of rats, only scotopic ERG a-wave, b-wave and OP amplitudes were measured.In Group A rats that were followed sequentially, all the ERG parameters recorded with attenuated stimuli showed significant time-dependent changes in glaucomatous eyes relative to their contralateral normal eyes, with OPs showing the earliest significant difference after only 3 weeks of high IOP. When different groups of unilateral glaucomatous rats were compared beyond 8 weeks of elevated IOP only the OPs showed a continued decrease with time and good discrimination between glaucoma and normal eyes. Over a 25 week period of high IOP the scotopic OPs measured with attenuated light stimuli declined at the rate of approximately 1.5% per week and provided the best ERG measure to monitor progression of retinal pathophysiology in the vein-occlusion rat glaucoma model., (Copyright 2001 Academic Press.)
- Published
- 2001
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8. Retinal morphology and ERG response in the DBA/2NNia mouse model of angle-closure glaucoma.
- Author
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Bayer AU, Neuhardt T, May AC, Martus P, Maag KP, Brodie S, Lütjen-Drecoll E, Podos SM, and Mittag T
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- Animals, Anterior Eye Segment pathology, Disease Models, Animal, Electroretinography, Glaucoma, Angle-Closure genetics, Glaucoma, Angle-Closure pathology, Light, Mice, Mice, Inbred C57BL, Mice, Inbred DBA, Photic Stimulation, Glaucoma, Angle-Closure physiopathology, Retina pathology, Retina physiopathology
- Abstract
Purpose: To document the time course of retinal dysfunction by scotopic electroretinography (ERG) and by quantitative morphology in eyes of the DBA/2NNia substrain of mouse (DBA) with inherited angle-closure glaucoma., Methods: DBA and control C57BL/6J (C57) mice were studied by ERG recordings from 5 to 15 months of age, and by morphology from 1 to 14 months of age. Scotopic ERGs were simultaneously recorded from both eyes of dark-adapted anesthetized mice. Changes in the central neuronal retina were evaluated by quantitative morphometry performed on serial semithin sections of Epon-embedded eyes., Results: When compared with normal C57 mice, DBA mice showed significant reductions of the a-wave and b-wave amplitudes by 7 to 8 months, and the decline continued as the animals aged. The b-wave implicit time in DBA mice showed a gradual prolongation beginning at 8 months of age, when compared with C57 mice. Logistic regression analyses revealed significant correlations in a- and b-wave amplitude reductions between ipsilateral and contralateral eyes of DBA mice at ages when ERG parameters were greatly altered. Morphologically, thinning of the whole retina was already evident in DBA mice at 4 months of age, but loss of ganglion cells and thinning of the outer plexiform layer were first seen in 7- to 8-month-old animals. These changes progressed to the end of the 13-month period studied., Conclusions: Progressive thinning of the outer retinal layers in DBA mice was found to correlate with decreases in ERG a- and b-wave amplitudes, both occurring from the age of 7 to 8 months onward. Similarities with the findings in human late-stage glaucomatous retinopathy indicate the relevance of this animal model in further glaucoma research.
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- 2001
9. Precision of tibial cartilage morphometry with a coronal water-excitation MR sequence.
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Hyhlik-Dürr A, Faber S, Burgkart R, Stammberger T, Maag KP, Englmeier KH, Reiser M, and Eckstein F
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- Adult, Aged, Algorithms, Female, Humans, Image Processing, Computer-Assisted, Knee pathology, Male, Middle Aged, Reproducibility of Results, Tibia pathology, Cartilage, Articular pathology, Knee Joint pathology, Magnetic Resonance Imaging methods, Osteoarthritis, Knee pathology
- Abstract
The aim of this study was to analyze the precision of tibial cartilage morphometry, by using a fast, coronal water-excitation sequence with high spatial resolution, to compare the reproducibility of 3D thickness vs volume estimates, and to test the technique in patients with severe osteoarthritis. The tibiae of 8 healthy volunteers and 3 patients selected for total knee arthroplasty were imaged repeatedly with a water-excitation sequence (image time 6 h 19 min, resolution 1.2 x 0.31 x 0.31 mm(3)), with the knee being repositioned between each replicate acquisition. After 3D reconstruction, the cartilage volume, the mean, and the maximal tibial cartilage thickness were determined by 3D Euclidean distance transformation. In the volunteers, the precision of the volume measurements was 2.3 % (CV%) in the medial and 2.6 % in the lateral tibia. The reproducibility of the mean cartilage thickness was similar (2.6 and 2.5 %, respectively), and that of the maximal thickness lower (6.5 and 4.4 %). The patients showed a considerable reduction in volume and thickness, the precision being comparable with that in the volunteers. We find that, using a new imaging protocol and computational algorithm, it is possible to determine tibial cartilage morphometry with high precision in healthy individuals as well as in patients with osteoarthritis.
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- 2000
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10. Comparisons of the amplitude size and the reproducibility of three different electrodes to record the corneal flash electroretinogram in rodents.
- Author
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Bayer AU, Mittag T, Cook P, Brodie SE, Podos SM, and Maag KP
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- Animals, Contact Lenses, Dark Adaptation physiology, Mice, Mice, Inbred C57BL, Photic Stimulation methods, Rats, Rats, Wistar, Reproducibility of Results, Species Specificity, Cornea physiology, Electroretinography, Microelectrodes, Retina physiology
- Abstract
To compare corneal electrodes commonly used in rodent eyes for repeat and left versus right eye accuracy and variability to record the flash electroretinogram (ERG). Animals studied were eight C57BL/6 mice and eight rats of the Wistar strain. Scotopic ERGs were recorded from eyes of dark-adapted anesthetized rodents to compare a custom-made gold-wire contact lens electrode (CLE), a cotton-wick silver-silver chloride electrode (SCLE), and a coiled stainless steel wire electrode (SSE). Compared to SCLE and SSE. the potentials recorded by CLE are characterized by significantly larger ERG amplitudes and oscillatory potentials in both rats and mice (p <0.0001). In analyzing test-retest data comparing the three different electrodes the coefficient of variation was smaller (range, 10.3-15.5%) and the interclass correlation coefficient (0.77-0.93) showed a better agreement for the CLE. Recording scotopic ERGs with custom-made gold-wire contact lens electrodes records large amplitudes and shows a good reproducibility and reliability to monitor retinal function in rodent eyes.
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- 1999
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11. Corpus callosum size in schizophrenia--a magnetic resonance imaging analysis.
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Meisenzahl EM, Frodl T, Greiner J, Leinsinger G, Maag KP, Heiss D, Hahn K, Hegerl U, and Möller HJ
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- Adult, Atrophy, Brain pathology, Case-Control Studies, Dominance, Cerebral, Humans, Magnetic Resonance Imaging, Male, Middle Aged, Psychiatric Status Rating Scales, Schizophrenia genetics, Corpus Callosum pathology, Genetic Predisposition to Disease psychology, Schizophrenia pathology
- Abstract
Previous MRI studies have shown differences in corpus callosum size between schizophrenic patients and controls. The corpus callosum (CC), as the main interhemispheric fiber tract, plays an important role in interhemispheric integration and communication. Though MRI studies suggest smaller CC in schizophrenia, there are still conflicting findings. Using in vivo magnetic resonance imaging, it was investigated whether the midsagittal area of CC differs between twenty-three right-handed male schizophrenic patients and twenty-three matched controls. Total CC area, five subregions of CC, total brain volume, gray and white matter were measured. No differences between schizophrenic patients and controls were found regarding all CC measurements, total brain volume, and gray matter tissue. However, a significant reduction of white matter tissue in the patient group emerged. There was no correlation between CC morphology and clinical variables such as age of onset, length of illness or symptom severity. Interestingly, five schizophrenic patients with a positive family history of schizophrenia showed significant reduction of the subregion C3, associated with a reduced total brain and gray and white matter volume. Significant reduction in the CC and its subregions was not confirmed in this group of patients with schizophrenia. In the subgroup of schizophrenic patients with a positive family history of schizophrenia, a significant reduction of the subregion corresponding to a part of the trunk of the CC was found.
- Published
- 1999
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12. Vestibular exercises improve central vestibulospinal compensation after vestibular neuritis.
- Author
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Strupp M, Arbusow V, Maag KP, Gall C, and Brandt T
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- Adult, Aged, Female, Humans, Male, Middle Aged, Posture, Prospective Studies, Spinal Nerves physiopathology, Time Factors, Treatment Outcome, Vestibular Nerve physiopathology, Vestibular Nuclei physiopathology, Visual Perception, Exercise Therapy, Neuritis therapy, Vestibular Diseases therapy
- Abstract
Objective and Background: Animal experiments have shown that central vestibular compensation of unilateral peripheral vestibular lesions can be improved by vestibular exercises. There are, however, no equivalent clinical studies on the efficacy of such specific physiotherapy on acute unilateral peripheral vestibular lesions in humans., Design and Methods: To quantify the differential effects of specific vestibular exercises on central compensation in patients with an acute/subacute unilateral vestibular lesion (vestibular neuritis), we determined the time course of recovery of 1) the ocular torsion (OT) for the vestibulo-ocular system, 2) the subjective visual vertical (SVV) for perception, and 3) the total sway path (SP) values for postural control in 19 patients with and 20 patients without vestibular exercises. All patients had a persisting peripheral vestibular deficit for at least 30 days (statistical end point)., Results: Although normalization of OT and SVV was similar in the control and physiotherapy groups, the total SP values on day 30 after symptom onset differed significantly: 3.2 +/- 1.9 m/min in the physiotherapy group and 16.9 +/- 6.1 m/min in the control group (ANOVA, p < 0.001)., Conclusions: This prospective clinical study suggests that specific vestibular exercises improve vestibulospinal compensation in patients with acute peripheral vestibular lesions.
- Published
- 1998
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13. In vivo reproducibility of three-dimensional cartilage volume and thickness measurements with MR imaging.
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Eckstein F, Westhoff J, Sittek H, Maag KP, Haubner M, Faber S, Englmeier KH, and Reiser M
- Subjects
- Adult, Female, Humans, Knee Joint anatomy & histology, Male, Middle Aged, Reproducibility of Results, Cartilage, Articular anatomy & histology, Image Processing, Computer-Assisted, Magnetic Resonance Imaging
- Abstract
Objective: Previous studies suggest that MR imaging is capable of providing accurate data on knee joint cartilage volume and thickness in vitro, but the reproducibility of these data in living subjects has not been analyzed rigorously. Our aim was therefore to determine the in vivo reproducibility of volume and thickness measurements from replicated data sets, applying three-dimensional (3D) postprocessing methods., Subjects and Methods: Eight healthy volunteers were imaged six times at a resolution of 2 x 0.31 x 0.31 mm with a fat-suppressed fast low-angle shot 3D sequence, the knee being repositioned in between replicated examinations. Three-dimensional reconstructions of the articular cartilage surfaces were obtained from sagittal data sets, and the cartilage volumes were calculated. The thickness distribution was analyzed throughout the joint surfaces independent of the section orientation, using a previously validated 3D minimal-distance algorithm., Results: In the volunteers, the coefficient of variation for replicated volume measurements ranged from 1.3% (patella) to 3.4% (lateral tibia), and the standard deviation of the individual cartilage volumes ranged from +/- 16% (lateral tibia) to +/- 22% (femur). The intraclass correlation coefficient ranged from .959 (lateral tibia) to .995 (patella). The interobserver evaluation was similar to the interscan reproducibility. The mean interscan deviation of the maximal cartilage thickness interval ranged from 0.1 to 0.3 cartilage thickness intervals (of 0.5 mm); only in rare cases did we record deviations greater than one thickness interval., Conclusion: MR imaging can be used to determine cartilage volume and thickness in the knee joints of living subjects with high precision, provided that a fat-suppressed gradient-echo sequence with adequate resolution and 3D digital image processing are used.
- Published
- 1998
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