Objectives In reconstructive surgery, flap monitoring is crucial for early identification of perfusion problems. Using hyperspectral imaging (HSI), this clinical study aimed to develop a non-invasive, objective approach for perfusion monitoring of free and pedicled flaps. Material and methods HSI of 22 free (FF) and 8 pedicled flaps (PF) in 30 patients was recorded over time. Parameters assessed were tissue oxygenation/superficial perfusion (0–1 mm) (StO2 (0–100%)), near-infrared perfusion/deep perfusion (0–4 mm) (NIR (0–100)), distribution of haemoglobin (THI (0–100)), and water (TWI (0–100)). Measurements up to 72 h were correlated to clinical assessment. Results Directly after flap inset, mean StO2 was significantly higher in FF (70.3 ± 13.6%) compared with PF 56.2 ± 14.2% (p = 0.05), whereas NIR, THI, and TWI were similar (NIR_p = 0.82, THI_p = 0.97, TWI_p = 0.27). After 24 h, StO2, NIR, THI, and TWI did not differ between FF and PF. After 48 h, StO2, NIR, and TWI did not differ between FF and PF whereas THI was significantly increased in FF compared with PF(p = 0.001). In three FF, perfusion decreased clinically and in HSI, 36(1), 40(2), 5(3), and 61(3) h after flap inset which was followed by prompt intervention. Conclusions StO2 < 40%, NIR < 25/100, and THI < 40/100 indicated arterial occlusion, whereas venous problems revealed an increase of THI. In comparison with FF, perfusion parameters of PF were decreased after flap transfer but remained similar to FF later on. Clinical relevance HSI provides objective and non-invasive perfusion monitoring after flap transplantation in accordance to the clinical situation. With HSI, signs of deterioration can be detected hours before clinical diagnosis.
The present study was conducted to evaluate the effects of nimodipine and mannitol on infarct size and on the amount of apoptosis after transient focal cerebral ischemia. Focal cerebral ischemia was induced in male Sprague-Dawley rats (weight 300-380 g) by transient occlusion of the right middle cerebral artery (MCAO) using an intraluminal thread model. All animals underwent ischemia for 2 h, followed by 24 h of reperfusion. Group I (n=16) was untreated. Group II (n=16) received 15% mannitol (1 g/kg as bolus) and group III (n=9) received 15 microg/kg/h nimodipine intravenously beginning 15 min prior to MCAO. Twenty-four hours after reperfusion, the brain was taken and sectioned in coronal slices. The slices were stained with H&E and with the transferase dUTP nick-end labeling (TUNEL) technique. Histopathological analysis revealed a significant (P<0.05) decrease in infarct size in the striatum with both drugs: mannitol (group II) 25.4+/-5.9% and nimodipine (group III) 21.5+/-11.0% versus control (group I) 34.9+/-7.0% and in the cortex 2.7+/-2.0% (group II) and 6.3+/-2.4% (group III) versus control 14.4+/-9.0% (group I). The number of apoptotic cells was statistically lower in the therapy groups (group III 9.6, group II 25.8) versus control (group I 57.9) (Mann-Whitney-Wilcoxon U-test Z>1.96, P<0.05). This study indicates that mannitol and nimodipine provide neuroprotection by preventing both the necrotic and apoptotic components of cell death after transient focal cerebral ischemia and may be effective as neuroprotective drugs for cerebrovascular surgery.
The development of microsurgical techniques offers a valuable opportunity to use small animals for experimental studies of vascularized organ transplants. Availability of inbred strains, natural resistance to infection, and economy make the rat an ideal animal model to investigate the effects of heart transplantation. The recent high interest and substantial laboratory activity with regard to posttransplantory immunological tissue reactions and apoptotic tissue processes led us to optimize transplantation technique by improving myocardial protection during ischemia and thereby minimizing adverse effects of the transplantation procedure itself. Thus the present report details the technique of heterotopic heart transplantation in rats using cardioplegic arrest.
MR tomography permits visual demonstration of flow and turbulence. A model was used to compare MR-measured signal intensities and flow profiles as obtained by Doppler anemometry.
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