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Ines Bolle

Publications and source records attributed to Ines Bolle.

5 recordsLinked to original sources
PubMed2006

Visualization of the visual cortex in minipigs using fMRI.

Minipigs are widely used to examine physiologic mechanisms under experimental settings. The purpose of our study was to localize the visual cortex of minipigs using visual stimulation in functional magnetic resonance imaging (fMRI). Five male Göttinger minipigs were studied with fMRI during visual stimulation with series of light impulses conducted into the MR cabin via fibre optical wave guides (EPI sequences, block design, 1.5 T clinical routine MR-scanner). Statistics were performed using SPM'99. All minipigs showed activation of the visual cortex due to light stimulation. The activation could be superimposed to T2-weighted structural images with good spatial resolution revealing the exact location of the visual cortex. We were able to localize the visual cortex in minipigs for the first time utilizing fMRI on a routine scanner. However, this may be useful for precise positioning of electrodes or implants or be used as a further uncomplicated non-invasive method in physiologic experiments.

Animals↗
PubMed2003

Chronically implanted epidural electrodes in Göttinger minipigs allow function tests of epiretinal implants.

BACKGROUND: To test the function of implantable devices for electrical stimulation of the retina, long-term registration tests of cortical-evoked potentials are required. Skin electrodes are not appropriate to provide representative recordings, due to the voluminous pneumatic frontal sinus of minipigs. Therefore, epidural electrodes were permanently implanted in minipigs and tested with visual and electrical retinal stimulation. The present study describes long-term recordings of electrically evoked cortical potentials in minipigs. METHODS: Three-channel silver-silver chloride electrodes were fixed on the epidura dorsal to the primary visual cortex of one hemisphere in Göttinger minipigs. Repeated light stimulation was performed and platinum-polyimide film multielectrode arrays were implanted on the retina for electrical stimulation and were later removed. Cortical potentials were recorded after stimulation with short biphasic charge-balanced currents. RESULTS: For up to 18 months, the implanted epidural electrodes allowed recording of visual cortex potentials evoked by visual or electrical retina stimulation. Small changes of response amplitudes in subsequent experiments indicated a stable location and recording properties of the cortex electrodes. Visual stimulation often yielded stronger responses for the contralateral eye. Superthreshold electrical retina stimulation evoked cortical responses with less delay compared to visual stimulation. We found threshold currents of 50 microA for charge-balanced biphasic trains of current impulses. Postoperative examination showed an attached and unchanged retina. CONCLUSIONS: The minipig model is appropriate for the implantation of epiretinal stimulation electrodes and for the long-term tests of retinal implants by recording of cortical responses with chronically implanted epidural electrodes.

Animals↗
PubMed2002

TNF-alpha antibodies are as effective as ischemic preconditioning in reducing infarct size in rabbits.

Pretreatment with tumor necrosis factor-alpha (TNF-alpha) antibodies abolishes myocardial infarct size reduction by late ischemic preconditioning (IP). Whether or not TNF-alpha is also important for myocardial infarct size reduction by classic IP is unknown. Anesthetized rabbits were untreated (group 1, n = 7), classically preconditioned by 5 min left coronary artery occlusion/10 min reperfusion (group 2, n = 6), or pretreated with TNF-alpha antibodies without (group 3, n = 6) or with IP (group 4, n = 6) before undergoing 30 min of occlusion and 180 min of reperfusion. Infarct size in group 1 was 44 +/- 11 (means +/- SD)% of the area at risk. With a comparable area at risk, infarct size was reduced to 13 +/- 7%, 23 +/- 8%, and 19 +/- 12% (all P < 0.05) in groups 2, 3, and 4, respectively. The circulating TNF-alpha concentration was increased during ischemia in group 1 from 752 +/- 403 to 1,542 +/- 482 U/ml (P < 0.05) but remained unchanged in all other groups. Circulating TNF-alpha concentration during ischemia and infarct size correlated in all groups (r = 0.76). IP, TNF-alpha antibodies, and the combined approach reduced infarct size to a comparable extent. Therefore, the question of whether or not TNF-alpha is causally involved in the infarct size reduction by IP in rabbits could not be answered.

Animals↗
PubMedDate not supplied

Intravenous infusion anesthesia with Propofol-Midazolam-fentanyl for experimental surgery in swine.

There is a need for prolonged anesthesia procedures in experimental surgery. Animals in this study received fentanyl, Midazolam, and Propofol administered by continuous intravenous infusion for anesthesia along with controlled ventilation. Time of anesthesia was 413 +/- 95 min. Animals could be extubated 20 +/- 12 min after operation. Animals recovered completely from anesthesia by day 1 after surgery with almost normal physical activity. This study clearly shows that intravenous infusion anesthesia is safe and easy to handle in prolonged anesthesia for experimental surgery in swine. This anesthetic protocol can also be used for intraoperative transportation.

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