Search results for "Rabbit."
showing 10 items of 552 documents
Vitrification of zona-free rabbit expanded or hatching blastocysts: a possible model for human blastocysts.
2003
BACKGROUND: The purpose of this study was to test the effectiveness of one two-step (A) and two one-step (B1 and B2) vitrification procedures on denuded expanded or hatching rabbit blastocysts held in standard sealed plastic straws as a possible model for human blastocysts. The effect of blastocyst size was also studied on the basis of three size categories (I: diameter <200 μm; II: diameter 200-299 μm; III: diameter ≥300 μm). METHODS: Rabbit expanded or hatching blastocysts were vitrified at day 4 or 5. Before vitrification, the zona pellucida was removed using acidic phosphate buffered saline. For the two-step procedure, prior to vitrification, blastocysts were pre-equilibrated in a solut…
Experimental reimplantation utilizing microvascular anastomosis in animals.
1977
Summary The use of the operating microscope and special microsurgical instruments make it possible to achieve successful anastomosis of blood vessels of less than 1 mm in diameter. Microvascular surgery offers newer possibilities in the transplantation of dermisfat grafts, and has led to an unusually high degree of success in the reimplantation of tissues. This paper describes a technique for microvascular anastomosis in animal experiment, using as a model the reimplantation of a completely amputated rabbit ear. In 10 amputated rabbit ears, the central auricular artery with a diameter of 0.5 mm and the two marginal auricular veins with diameter of 0.5–1.0 mm were microsurgically anastomosed…
Neuronal and extraneuronal uptake and efflux of catecholamines in the isolated rabbit heart
1974
1. Isolated rabbit hearts were perfused with (−)-noradrenaline, (−)-adrenaline and (±)-isoprenaline for various time periods (1–180 min) and then washed with an amine-free medium. The venous concentration of the amine was estimated fluorimetrically during the infusion and after its end, to study removal and efflux, respectively. 2. In untreated hearts and after pretreatment with reserpine the removal had a constant rate over 20–60 min. After pretreatment with pargyline to block monoamine oxidase (MAO), however, the removal of noradrenaline declined exponentially to zero. Inhibition of the neuronal uptake (desipramine) and chemical sympathectomy (6-hydroxydopamine) abolished the removal of n…
The neuronal efflux of noradrenaline: Dependency on sodium and facilitation by ouabain
1974
Rabbit hearts were isolated after pretreatment with the MAO inhibitor pargyline and with reserpine and were perfused with 200 ng/ml noradrenaline for 1 h. During the subsequent wash-out with an amine-free solution for 2 h, the neuronal efflux of noradrenaline declined mono-exponentially with a mean halftime of 42 min. Both Na+-free solution and ouabain caused facilitation of the efflux which thereafter declined in a multi-exponential fashion. The maximum facilitation was reached after 3 min of Na+-free perfusion and 25 min after introduction of ouabain. The amount of exogenous noradrenaline accumulated in the heart was only partially released when the extracellular Na+-concentration was nor…
Evaluation of the Complexity of Myocardial Activation During Ventricular Fibrillation. An Experimental Study
2013
A B S T R A C T Introduction and objectives: An experimental model is used to analyze the characteristics of ventricular fibrillation in situations of variable complexity, establishing relationships among the data produced by different methods for analyzing the arrhythmia. Methods: In 27 isolated rabbit heart preparations studied under the action of drugs (propranolol and KB-R7943) or physical procedures (stretching) that produce different degrees of change in the complexity of myocardial activation during ventricular fibrillation, use was made of spectral, morphological, and mapping techniques to process the recordings obtained with epicardial multielectrodes. Results: The complexity of ve…
PPARγ as an indicator of vascular function in an experimental model of metabolic syndrome in rabbits
2021
Abstract Background and aims Underlying mechanisms associated with vascular dysfunction in metabolic syndrome (MetS) remain unclear and can even vary from one vascular bed to another. Methods In this study, MetS was induced by a high-fat, high-sucrose diet, and after 28 weeks, aorta and renal arteries were removed and used for isometric recording of tension in organ baths, protein expression by Western blot, and histological analysis to assess the presence of atherosclerosis. Results MetS induced a mild hypertension, pre-diabetes, central obesity and dyslipidaemia. Our results indicated that MetS did not change the contractile response in either the aorta or renal artery. Conversely, vasodi…
Focal elevation of liver microsomal epoxide hydrolase in early preneoplastic stages and its behaviour in the further course of hepatocarcinogenesis.
1981
Abstract Treatment of rats with N-nitrosomorpholine (NNM) for 7 weeks led to a focal increase in liver microsomal epoxide hydrolase (EH) as early as 2 weeks after withdrawal of the carcinogen. This treatment also leads to hyperplastic nodules and liver tumors, but much later. At the same early time point, ATPase activity was decreased in the same islands. Most of these areas already had increased γ-glutamyltranspeptidase activity. The increase in EH at this early time point was more distinct than the decrease in ATPase which has thus far been considered a suitable marker of the earliest stages in hepatocarcinogenesis. The focal increase in EH was also observed in all benign hepatomas, but n…
Quantitative study of muscle fibre atrophy and restitution after nerve grafts.
1976
Our comparative experimental studies on rabbits using clinical, electromyographical, and quantitative histological examinations of long autologous and homologous nerve grafts in 35 rabbits, paying special attention to quantitative histological changes in the gastrocnemius muscles, allow the statement that, compared to the short homografts, the long homografts showed worse results. Moreover, it became obvious that the regeneration rate of autografts was not influenced by increasing the lengths of the grafts. The answer to the question of how far even longer grafts may influence the quality of regeneration will need further investigations.
On the Number of Measurements Necessary to Assess Regional Cerebral Blood Flow by Local Laser Doppler Recordings: A Simulation Study with Data from 4…
1995
Laser Doppler fluxmetry may improve the monitoring of cortical blood flow in neurosurgical patients. So far, however, the variability of laser Doppler readings found in the cerebral cortex has prevented a consequent usage of the technique in clinical practice. The current report analyzes the regional variability of laser Doppler readings from experimental animals. Typical frequency histograms of observed flow values display non-Gaussian distributions. A simulation technique is used to assess the number of measuring sites required for valid estimates of regional cortical flow. From a total of 990 local flow measurements from 45 rabbits random samples of sizes between 5 and 100 were repeatedl…
Evidence for a respiration-modulated cholinergic action on the activity of medullary respiration-related neurons in the rabbit. An iontophoretic stud…
1989
Effects of the iontophoretically administered cholinergic agonists acetylcholine, bethanechol and DMPP on the activity of medullary respiration-related neurons were examined in urethane-anaesthetized rabbits. Inhibitory effects prevailed over excitatory effects. Analysis of cholinergic effects by cycle-triggered averaging revealed three major types of neuronal responses: (i) constant alterations of spike-density throughout the whole period of activity ("constant effects"), (ii) effects increasing during the progression of the burst of discharge or effects restricted to a particular fraction of the burst ("phasic effects") and (iii) effects which were characterized by an excitation during on…