Search results for "Perfusion"
showing 10 items of 714 documents
Investigating drug absorption from the colon: Single-pass vs. Doluisio approaches to in-situ rat large-intestinal perfusion
2017
Traditionally, the colon is considered a secondary intestinal segment in the drug absorption process. However, in many cases the role of colonic drug permeability cannot be overlooked. The purpose of this research was to compare colon permeability data obtained using two different rat perfusion methods the single-pass intestinal perfusion (SPIP) approach and the closed-loop (Doluisio) perfusion model. A list of 14 structurally diverse model drugs was constructed, and their rat colon permeability was studied using the two methods. The two sets of results were compared to each other, and were evaluated vs. in-vitro, ex-vivo, and in-vivo literature values. The SPIP and the Doluisio results exh…
Segmental-dependent permeability throughout the small intestine following oral drug administration: Single-pass vs. Doluisio approach to in-situ rat …
2016
Abstract Intestinal drug permeability is position dependent and pertains to a specific point along the intestinal membrane, and the resulted segmental-dependent permeability phenomenon has been recognized as a critical factor in the overall absorption of drug following oral administration. The aim of this research was to compare segmental-dependent permeability data obtained from two different rat intestinal perfusion approaches: the single-pass intestinal perfusion (SPIP) model and the closed-loop (Doluisio) rat perfusion method. The rat intestinal permeability of 12 model drugs with different permeability characteristics (low, moderate, and high, as well as passively and actively absorbed…
A significant p value is not equivalent to the superiority of one test index over another
2019
Background In patients with septic shock, the skin is often chosen for the evaluation of peripheral perfusion and oxygenation. Changes in skin microcirculatory vessel oxygen saturation and relative hemoglobin concentration can be described using a mottling score or captured with hyperspectral imaging. However, the effectiveness of the mottling score in assessing microcirculation remains to be shown. We hypothesize that the mottling score in patients with septic shock is related to skin microcirculatory perfusion indices quantified by hyperspectral imaging, biomarkers that reflect endothelium activation and damage, and clinical outcome. Methods Hyperspectral imaging of the knee area was perf…
RELATIONSHIP BETWEEN THEOPHYLLINE UPTAKE AND INOTROPIC EFFECT IN THE GUINEA-PIG HEART
1974
1 The time course of the positive inotropic effect of theophylline was compared with the time course of the uptake and release of [(3)H]-theophylline in guinea-pig isolated, electrically driven hearts perfused by the Langendorff method.2 Formation of theophylline metabolites could not be detected under the experimental conditions used.3 Theophylline entered myocardial tissue very rapidly in two different phases. The first process (half-time 21 s) amounted to 93% and the second (half-time 5 min 50 s) to 7% of the total uptake. The development of the positive inotropic effect of theophylline was about four times faster than even the rapid component of the uptake of the drug into the myocardiu…
Evaluation of left ventricular mass on cadmium-zinc-telluride imaging: Validation against cardiac magnetic resonance
2017
Background. Single-photon emission computed tomography has shown relevant limitations in the quantification of left ventricular (LV) mass. We sought to compare the estimates of LV mass on Cadmium-Zinc-Telluride (CZT) myocardial perfusion imaging (MPI) as compared to cardiac magnetic resonance (CMR). Methods and results. Twenty-five patients underwent MPI on a CZT camera and CMR on a 1.5 T scanner within 12 ± 3 weeks. LV mass was quantified on CZT images using two softwares: 4D-MSPECT (4DM) and Emory Cardiac Toolbox (ECTb). LV mass by CMR was quantified using MASS software (Medis, Leiden, The Netherlands). LV mass values obtained with 4DM and ECTb were highly reproducible [intraclass correla…
Blood constituents trigger brain swelling, tissue death, and reduction of glucose metabolism early after acute subdural hematoma in rats
2009
Outcome from acute subdural hematoma is often worse than would be expected from the pure increase of intracranial volume by bleeding. The aim was to test whether volume-independent pathomechanisms aggravate damage by comparing the effects of blood infusion with those of an inert fluid, paraffin oil, on intracranial pressure (ICP), cerebral perfusion pressure (CPP), local cerebral blood flow (CBF), edema formation, glucose metabolism ([18F]-deoxyglucose, MicroPET), and histological outcome. Rats were injured by subdural infusion of 300 μL venous blood or paraffin. ICP, CPP, and CBF changes, assessed during the first 30 mins after injury, were not different between the injury groups at most …
Intraoperative monitoring of cerebral blood flow during ventricular shunting in hydrocephalic pediatric patients.
1995
Several studies have demonstrated lowered cerebral blood flow (CBF) in patients with hydrocephalus and symptoms of raised intracranial pressure. Ventricular shunting in such cases permits a sudden increase in CBF. The pathophysiology of functional brain deficit secondary to hydrocephalus is little understood. Improvement of the patient's clinical status after drainage of CSF suggests that cerebral dysfunction is not necessarily due to permanent brain damage. In fact, it improves rapidly after ventricular taps. In view of this it would be helpful to monitor cerebral perfusion. The transcranial Doppler (TCD) ultrasonography technique allows real-time monitoring of the intracranial circulation…
Similar level of metabolic activation of benzo(a)pyrene in perfused rat lung and liver and protection of lung by liver in a combined perfusion system
1982
Abstract Irreversible binding of metabolically activated benzo(a)pyrene to DNA, RNA and protein proceeds by a different time course in perfused liver and lung of 5,6-benzoflavone-treated rats. Peak binding in liver is obtained after 15 min while binding in lung continuously increases over 120 min. Total irreversible binding per mg DNA or RNA is in the same order of magnitude in both organs. While binding in lung is lower at 15 min it exceeds binding in liver at 120 min. Binding per mg protein is higher in lung than in liver over the whole perfusion period. Introduction of a liver into the lung perfusion circuit decreases binding in lung. This protection effect is more pronounced when the li…
The antibiotic erythromycin induces tolerance against transient global cerebral ischemia in rats (pharmacologic preconditioning).
2006
Background Cerebral ischemic tolerance can be induced by a variety of noxious stimuli, but no clinically applicable regimen for preconditioning has been described. Therefore, the authors tested the ability of a pharmacologic preconditioning strategy using the well-known macrolide antibiotic erythromycin to induce tolerance against transient global cerebral ischemia in vivo. They also investigated whether tolerance induction by erythromycin involves transcriptional and translational changes of cerebral B-cell leukemia/lymphoma-2 (bcl-2) expression. Methods Male Wistar rats were treated with erythromycin (25 mg/kg intramuscularly) or vehicle and subjected to 15 min of transient global cerebr…