shu-508 and Disease-Models--Animal

The effect of transmyocardial laser revascularization (TMLR) on microperfusion and oxygen supply was studied in an acute ischemia model, using 35 pigs, with 13 serving as controls.. Measurement of tissue oxygen tension was compared with the semiquantitative measurement of microperfusion using contrast echocardiography and infrared laser Doppler. All methods were used before and after coronary occlusion and after TMLR. Effects were measured in the ischemic area and in two ischemia independent areas.. At baseline, oxygen partial pressure was 54.2 +/- 15.7 mmHg and decreased to 2.8 +/- 1.4 mmHg ( P < 0.05) after occlusion. After TMLR, oxygen tension increased to 27.3 +/- 8.5 mmHg ( P < 0.05) in the ischemic area, indicating a significant effect of TMLR on microperfusion and oxygen tension. Changes in regional oxygen tension corresponded to Levovist density changes in contrast echocardiography and changes in microperfusion measured by infrared laser Doppler.. Our data indicate that measurement of tissue oxygen tension is a suitable experimental tool to assess the effect of TMLR on myocardial perfusion, which cannot be discriminated using clinical imaging methods.

Topics: Acute Disease; Animals; Contrast Media; Coronary Circulation; Disease Models, Animal; Echocardiography; Electrochemistry; Ion-Selective Electrodes; Laser Therapy; Laser-Doppler Flowmetry; Lasers, Excimer; Male; Microcirculation; Myocardial Ischemia; Myocardial Revascularization; Myocardium; Oxygen; Partial Pressure; Polysaccharides; Reproducibility of Results; Swine

To investigate Kupffer cell dynamics and phagocytic activity, using a rat nonalcoholic steatohepatitis (NASH) model.. Male F344 rats were fed either a control diet or a choline-deficient L-amino acid-defined (CDAA) diet, followed by contrast enhanced ultrasonography (CEUS) using Levovist. The uptake of latex beads by the Kupffer cells was determined by fluorescent microscopy. The status of the Kupffer cells was compared between the two groups, using the immunohistochemical staining technique.. After 4 or more wk of the CDAA diet, CEUS examination revealed a decrease in the signal intensity, 20 min after intravenous Levovist. Fluorescent microscopic examination showed that the uptake of latex beads by the Kupffer cells was reduced at week 1 and 2 in the study group, compared with the controls, with no further reduction after 3 wk. Immunohistochemical staining revealed no significant difference in the Kupffer cell counts between the control group and the CDAA group.. CEUS examination using Levovist demonstrated reduced contrast effect and phagocytic activity in the liver parenchymal phase, although the Kupffer cell numbers were unchanged, indicating reduced phagocytic function of the Kupffer cells in the rat NASH model. We believe that CEUS examination using Levovist is a useful screening modality, which can detect NASH in fatty liver patients.

Topics: Alanine Transaminase; Animals; Cells, Cultured; Contrast Media; Disease Models, Animal; Fatty Liver; Hepatitis; Kupffer Cells; Liver; Male; Mass Screening; Microspheres; Phagocytosis; Polysaccharides; Rats; Rats, Inbred F344; Ultrasonography

To evaluate the potential diagnostic advantages of the contrast agent Levovist for signal enhancement of small adjoining fetal vessels and to study the effect of Levovist before and during acute fetal hypoxia on the fetal circulation and the fetal blood flow velocities.. A prospective, randomized study was performed in 12 fetal sheep before and during acute fetal hypoxia produced by complete occlusion of the maternal common iliac artery. Two groups of animals were studied, comprising animals with (study group, n = 6) and without (control group, n = 6) Levovist. In the study group, Levovist was administered intravenously by a pump (modified IVAC P 4000, Schering, Berlin). Duration and intensity of signal enhancement were measured in the fetal aorta, the common carotid artery and the ophthalmic artery of both groups before and during hypoxia. Concurrently, fetal heart rates as well as systolic and diastolic blood flow velocities in all three vessels were recorded in both groups.. The increased signal intensity of up to 15 dB in the study group resulted in improved differentiation and imaging quality of adjoining small fetal vessels when compared with the control group. Neither before nor during acute hypoxia, significant differences of the fetal heart rate and the systolic and diastolic blood flow velocities were observed between the two groups (p > 0.05). In the study group, no emboli were caused by Levovist in any fetal tissue or in the placenta.. The contrast agent Levovist improves the detection and accuracy of monitoring flow velocities in small fetal vessels by increasing the intensity of the Doppler signal without affecting fetal heart rate or fetal blood flow velocities.

Topics: Acute Disease; Animals; Blood Flow Velocity; Contrast Media; Disease Models, Animal; Female; Fetal Blood; Fetal Heart; Fetal Hypoxia; Fetus; Heart Rate, Fetal; Placental Circulation; Polysaccharides; Pregnancy; Prospective Studies; Random Allocation; Sheep; Ultrasonography, Doppler, Duplex; Ultrasonography, Prenatal

Unilateral intracarotid injection of contrast agents may considerably destabilize the blood-brain barrier in rats. This leads to vasogenic edema in the ipsilateral hemisphere. Mortality and extravasation increased significantly when administration of these ultrasound contrast agents was followed by mild traumatic brain injury. Direct administration to the cerebral circulation is, therefore, indicative for edema-related pathology and may amplify the consequences of experimental neurotrauma.

Topics: Albumins; Animals; Blood-Brain Barrier; Brain Edema; Brain Injuries; Contrast Media; Disease Models, Animal; Dose-Response Relationship, Drug; Extravasation of Diagnostic and Therapeutic Materials; Fluorocarbons; Functional Laterality; Injections, Intra-Arterial; Male; Nerve Degeneration; Polysaccharides; Rats; Ultrasonography

The induction by ultrasound (US) of petechiae and hemorrhages in mouse intestine was examined with injection of gas body-based contrast agents. Production of petechiae in the intestinal wall was enhanced by contrast agents for both continuous and pulsed (10 micros pulses repeated at 1 kHz) exposure relative to a gas body-free blank. For pulsed exposure with 10 mL/kg of Albunex, apparent thresholds for peak negative pressure amplitude were 0.42 MPa at 0.4 MHz, 0.85 MPa at 1.09 MHz and 2.3 MPa at 2.4 MHz. Results at these frequencies were the same for 10-11 cycle pulses with fixed duty cycle (0.01). Thresholds for hemorrhage into the intestinal lumen were not appreciably enhanced by added Albunex, and appear to be compatible with previously reported lithotripsy data when duty factor differences are considered. The agents PESDA, Optison and Levovist had lower thresholds (for example, 1.8 MPa for Levovist) than Albunex at 2.3 MHz, and yielded more petechiae. The thresholds for petechiae induction by US with contrast agents encroach upon the exposure range relevant to diagnostic US practice.

Topics: Albumins; Animals; Contrast Media; Disease Models, Animal; Fluorocarbons; Gastrointestinal Hemorrhage; Intestinal Diseases; Intestines; Male; Mice; Mice, Hairless; Microspheres; Polysaccharides; Purpura; Ultrasonography

The purpose of this study was to estimate the size required for small vessels to become detectable with color Doppler sonography. A murine experimental tumor was examined with color Doppler sonography after injection of 1.5 mL of the contrast medium Levovist. Histologically, we measured vessel diameters inside the tumor, as well as in its direct neighborhood. With color Doppler at a transmit frequency of 7 MHz, vessels were only detected in the tumor's environment, but not inside. By histology, the 95% quantile of the vessel diameter distribution was found to be 21 microm inside the tumor, 37 microm in the underlying muscle, and 73 microm in the directly adjacent connective tissue. Vessels in the upper range of the size distribution in the muscle and connective tissue are probably detectable. Using the 95% quantile as an estimate, and correcting the values for possible shrinkage, using a factor of 1.91 reported in the literature, vessels in the 74-134 microm range may be detected under the given conditions, whereas vessels measuring 38 microm or less are inaccessible to color Doppler.

Topics: Animals; Contrast Media; Disease Models, Animal; Male; Neoplasm Transplantation; Polysaccharides; Prostatic Neoplasms; Rats; Sensitivity and Specificity; Thigh; Ultrasonography, Doppler, Color

The purpose of this study was to determine the usefulness of contrast-enhanced sonography in the detection of acute parenchymal injury.. In a model of acute renal injury in pigs, four separate renal parenchymal bleeds were created by puncturing an interlobar artery of the upper and lower poles of the kidneys. B-mode gray-scale scans of the kidneys before and after injury, and after the administration of i.v. and intraarterial (i.a.) contrast agents were recorded on videotape for 5 min for each condition (baseline, after injury, after i.v. contrast administration, and after i.a. contrast administration). For each condition and injury, selected frames were analyzed with regions of interest of the normal renal parenchyma, the area of injury, and the perinephric space. Randomized videotape clips from each of the experimental conditions were rated by three sonologists as to the presence or absence of increased intrarenal parenchymal echogenicity, perinephric echogenicity, and confidence as to whether renal injury was present.. Areas of renal injury were isoechoic with normal parenchyma on unenhanced scans. After both i.v. and i.a. contrast material injection, areas of injury were visible as areas of increased echogenicity. Contrast increased from 0.2 on unenhanced images to 4.0 and 4.5, respectively, after i.v. and i.a. administration of the new contrast agent. The three observers' ability to diagnose renal injury increased from 0.61, 0.64, and 0.54 to 0.71, 0.70, and 0.74 after i.v. injection and to 0.93, 0.92, and 0.97 after i.a. injection as indicated by the area under the curve in the receiver operating characteristic analysis.. Transabdominal contrast-enhanced gray-scale sonography can reveal the area of acute renal hemorrhage. This procedure may be applicable in patients when sonographic contrast agents, imaging procedures, and modes of contrast administration are optimized for clinical use in trauma.

Topics: Animals; Contrast Media; Disease Models, Animal; Hemorrhage; Kidney; Observer Variation; Polysaccharides; Swine; Ultrasonography

A galactose-based sonographic contrast agent, which produces stable microbubbles capable of traversing the cardiopulmonary circulation, was used to enhance Doppler signals in blood vessels of varying size after intravenous injection. A series of experiments using dogs, rabbits, and woodchucks was conducted to establish the ability of the agent to enhance the reflectivity of normal tissue, tumor tissue, and blood. Although no enhancement was perceptible in tissue on the sonogram, significant enhancement of color and spectral Doppler signals was demonstrated in a variety of vessels. These included the aorta, vena cava, and portal vein as well as such small vessels as those of the retina of the eye, renal cortex, liver parenchyma, and gallbladder wall. Both spectral and color Doppler enhancement was shown in naturally occurring woodchuck hepatomas. Peak Doppler signal enhancement after bolus injection was approximately 10 dB with a dose of 0.01 ml/kg. Recirculation of the agent provided enhancement after intravenous bolus injection for more than 3 min. With a steady intravenous infusion of 0.2 ml/min/kg, Doppler signal enhancement of about 14 dB was maintained continuously for more than 5 min. The results of these animal experiments, in particular in small vessels and with recirculation after intravenous injection, suggest excellent potential for future clinical applications.

Topics: Angiography; Animals; Blood Flow Velocity; Blood Vessels; Contrast Media; Disease Models, Animal; Dogs; Eye; Galactose; Gallbladder; Infusions, Intravenous; Injections, Intravenous; Liver Neoplasms, Experimental; Marmota; Polysaccharides; Rabbits; Renal Artery Obstruction; Ultrasonography