PURPOSE: To assess the signal enhancement by gadolinium-DTPA-polylysine (Gd-polylysine) as compared to gadopentetate (Gd-DTPA) in MR imaging of heart that have undergone ischemia-reperfusion, and to estimate the extent of myocardial damage covered bythe MR signal enhancement. MATERIALS AND METHODS: A series of contrast enhanced cardiac MR images were obtained from 17 cats subjected to a 90 minutes of occlusion of the left anterior descending coronary artery (LAD) followed by a 90 minutes of raperfusion. Time courses of changes in the signal intensity (Sl) of the ischemic area were measu red in Gd-polylysine group (8 cats) and Gd- DTPA group (9 cats). The size of U R signal enhanced area was then compared to the sizes of infarction and the area at risk revealed byTTC histochemical staining. RESULTS: Maximum Sis were obtained at 60 minutes and 30 minutes after injection of the contrast material, respectively for Gd-polylysine group and Gd-DTPA group. Signal enhancement was stronger and persistent for a longer period in Gd-polylysine group than in GD-DTPA group. Sizes of the enhanced area, the infarction, and the area at risk were about 30%, 15%, and 50% of the total left ventricle (LV) area; the difference between the groups was statistically insignificant. CONCLUSION: Gd-polylysine can be used better for a blood pool marker than Gd-DTPA in MR imaging of myocardial ischemia, due to its strong and persistent signal enhancement. The MR signal enhanced area includes both the infarcted area and a portion of the area at risk.
Animals ; Cats* ; Coronary Vessels ; Gadolinium DTPA ; Gadolinium* ; Heart ; Heart Ventricles ; Infarction ; Magnetic Resonance Imaging* ; Myocardial Ischemia ; Pentetic Acid ; Polylysine*

This study was performed to assess the accuracy of 31P magnetic resonance spectroscopy(MRS) in the evaluation of myocardial ischemia in cats. Twelve cats underwent myocardial ischemia and reperfusion induced by 90 minutes ligation followed by 90 minutes recirculation of the left anterior descending coronary artery (LAD). MRS was performed using a 4.7T Biospec MRS/MRI system (Bruker, Switzerland). An inner diameter 1.5cm-sized doubly tuned surface coli was used for the collection of the MR signal. The coli was implanted to the epicardial surface at the expected area of infarction. 31P MRS was acquired before and during the periods of ischemia and reperfusion with 5-minute to 30-minute of intervals. After completion of the 31P MRS study, animals were sacrificed and the hearts were excised for 2,3,5-triphenyl tetrazolium chloride (TTG0 histochemical staining. The area of infarct was measured on the photographs of TTG stained heart slices using a computer programmed planimetry and the results were compared with those of the 31P MRS study. The level of phosphocreatine (PCr) was decreased to 28.2±6.9% of the baseline level 90 minutes after occlusion and recovered to 43.8±4.8% of the baseline level at the end of the reperfusion. A 50% depletion of PCr was reached 5 minutes after the LAD occlusion. The ATP was decreased to a 26.6±3.6% of the baseline level 90 minutes after occlusion and recovered to a 35.9±6.0 of the baseline level 90 minutes after reperfusion. The decreasing rate of ATP was slower than that of PCr showing a 50% of depletion 15 minutes after occlusion. The PCr/ATP ratio was 1.16±0.09 at the baseline, decreased to 0.88±0.07 at 30 minutes of occlusion, and then progressively increased during the late ischemic and reperfused periods. The ratio of the infarcted area to the effective signal area of the surface coli was inversely correlated to the ATP (r=0.68) and PCr (r=0.40) levels obtained at the end of reperfusion. In conclusion, 31P MRS reflects the changes in myocardial high energy phosphorous metabolism during the actue ischemia and reperfusion. If on adequate localization technique is feasible, 31P MRS can be used clinically in the diagnosis and monitoring of the patients with acute myocardial infarction.
Adenosine Triphosphate ; Animals ; Cats* ; Coronary Vessels ; Diagnosis ; Heart ; Humans ; Infarction ; Ischemia ; Ligation ; Metabolism ; Myocardial Infarction* ; Myocardial Ischemia ; Phosphocreatine ; Polymerase Chain Reaction ; Reperfusion ; Spectrum Analysis*

No abstract available.
Polycystic Kidney Diseases*

PURPOSE: To see the stability and error in the diffusion-weighted magnetic resonance (MR) imaging technique in the experimental models and to observe the signal intensities in the early cerebral lesions of the animal models. MATERIALS AND METHODS: Diffusion coefficients of acetone and distilled water were measured by diffusion-weighted MR image and were compared with actual values. Differentiation of diffusion from perfusion were done at the resin flow phantom. The signal intensities caused by early parenchymal changes were measured in normal, hypovolemic, and embolic, and dead animal models by using diffusion-weighted image and compared with pathoIogic finding and vital staining. RESULTS: Diffusion coefficients of acetone and distilled water were 4.48 x 10-3 and 2.72 x 10-3 which were very close to the actual values. Diffusion-weighted MR image obtained at flow phantom was not affected by flow (perfusion) at the 100-400 of b-factor range. Animal study done at that b-factor range revealed a significant signal difference between the left and right sides only at the embolic model induced by polyvinyl alchol particles (p<0.05). These changes were not detected in microscopic finding but could be identified in vital staining. CONCLUSION: Diffusion-weighted MR image can be used to detect early parenchymal change when the appropriate b-factor range was applied.
Acetone ; Animals ; Diffusion* ; Hypovolemia ; Models, Animal ; Models, Theoretical* ; Perfusion ; Polyvinyls ; Water

BACKGROUND: Reestabilshment of blood flow is a standard therapeutic modality to salvage the myocardium at risk in an acute phase of myocardial infarction. However, there are significant evidences that reperfusion per se may injure the potentially viable myocardium, and a number of pharmacological agents were tried to reduce this reperfusion injury. Adenosine, an endogenous vasodilator, is suggested to reduce repergusion inury. To evaluate the myocardial protective effect of adenosine, magnetic resonance spectroscopy with superscript P was applied to feline model of acute myocardial ischemia-reperfusion, as well as pathological examination. METHODS: Effects of adenosine on the recovery of high energy phosphorous metabolites during 90 minutes of reperfusion period following 90 minutes of left anterior descending coronary artery ligation were assessed by31P spectroscopy in 27 cats(10: control group, 8: adenosine I group, 9: adenosine II group). In adenosine groups 0.2 mg/kg/min of adenosine was infused intravenously for 90 minutes from 30 miniutes before reperfusion in group I, and from just before reperfusion in group II. The experiments were performed on a 4.7 T/30 cm Biospec MRS/MRI system and the MR signals were obtained by using inner-diameter 1.5 cm-sized doubly tuned surface coil. The size of the spectral peaks was measured by area integration method. RESULTS: 1) Phosphocreatine(PCr) decreased rapidly with progression of ischemia, and recovered in reperfusion period in each group. PCr values in the reperfusion period were significantly higher in adenosine group than those in control group, although there was no difference between adenosine group I and II. 2) ATP decreased with progression of ischemia, and recovered in reperfusion period in each group. ATP values in the reperfusion period were significantly higher in adenosine groups than those in control group, byt there was no difference between adenosine group I and II. 3) pH decreased uniformly with progression of ischemia and recovered in reperfusion period, showing no difference between control and adenosine groups. 4) PCr/ATP ratio, representing the potential of oxidative phosphorylation, dereased with progression of ischemia and increased in reperfusion period. PCr/ATP ratio showed no difference between control, adenosine I and II groups. 5) Risk area/left ventricle ratio was not different in control and adenosine groups. Infarct size/risk area and infarct size/left ventricle ratios were smaller in adenosine II than those in control group. Howerver no significant diffence was noticed between adenosine I and control, and between adenosine I and II group. CONCLUSION: Intravenous infusion of adenosine showed the tendency of reducing the infarct size in the feline model of acute myocardial ischemia-reperfusion, and adenosine could improve significantly the recovery of high energy phosphate metabolites. This myocardial pretective effect of adenosine is considered to be present mainly in the reperfusion period.
Adenosine Triphosphate ; Adenosine* ; Coronary Vessels ; Hydrogen-Ion Concentration ; Infusions, Intravenous ; Ischemia ; Ligation ; Magnetic Resonance Spectroscopy ; Myocardial Infarction ; Myocardial Ischemia ; Myocardium ; Oxidative Phosphorylation ; Polymerase Chain Reaction ; Reperfusion ; Reperfusion Injury ; Spectrum Analysis

BACKGROUND: To evaluate the metabolic and pathological changes associated with myocardial ischemia-reperfusion, magnetic resonance spectroscopy with 31P was applied as well as pathological examination. METHODS: Effect of adenosine on the recovery of high energy phosphorous metabolites during the reperfusion period following 90 minutes of left anterior descending coronary artery(LAD) ligation was assessed by 31P spectroscopy in 13 cats(8 : control group, 5 : adenosine group). In adenosine group 0.2 mg/kg/min of adenosine was infused intravenously for 90 minutes from 30 minutes before reperfusion. The experiments were peformed on a 4.7 T/30cm Biospec MRS/MRI system(Bruker, Switzerland) and the MR signals were obtained by using innerdiameter 1.5 cm sized doubly tuned surface coil. The size of the spectral peaks was measured by area integration method. RESULTS: In control group, high energy phosphorous metabolites decreased continueously during the ischemic period revealing the lowest values at the end of the periods : 17.0% for PCr and 24.0% for ATP, PCr depleted below 50% of the baseline level immediately after the LAD ligation and ATP, after 15 minutes of ischemia. Therfore the depletion rate was faster in PCr change than in ATP. The recovery of the PCr and ATP occurred after reestablishment of blood flow showing, for example, 43.3% and 36.3% of the baseline levels after 10 minutes of reperfusion. After infusion of adenosine, there was a tendency of higher recovery rates of high energy phosphates than in control group. Recovery rates of PCr and ATP after 90 minutes of reperfusion, were 28.2%, 11.2% in control group and 38.3%, 18.6% in adnosine group, respectively. In adenosine grop, relative sizes of infarction were not statistically different from those of control group. CONCLUSIONS: 31P MRS can be used for in-vivo assessment of the changes of high energy phosphorous metablites concerning acute myocardial ischemia and reperfusion. Adenosine infusion improves the recovery of ATP and PCr during the reperfusion period following acute ischemia.
Adenosine Triphosphate ; Adenosine* ; Animals ; Cats* ; Infarction ; Ischemia ; Ligation ; Magnetic Resonance Spectroscopy ; Myocardial Ischemia ; Phosphates ; Polymerase Chain Reaction ; Reperfusion ; Spectrum Analysis

In order to observe the pattern of a flow image on multisection MR imaging technique, a flow phantom experiment was preformed using a superconducting high filed 2.0 Tesla MRI scanner. The pattren of the first section images was homogeneous round at all flow velocities until the turbulence forming level. The patterns of the second section images,however,changed into a homogeneous round shape, a ring shape, a target shape, and a small round shape as the velocity increased. When scanned at velocities higher than the trubulence forming level, the images become distored and irregular, and eventually disappeared after the cut-off velocity. The homogeneous round image senn at the lower velocity levels in throught to be due to the overwhelming effects of fully managetized spins influxed into the imaging section during the prior repetition time(TR). Later in the higer velocity levels the effects of the partially saturated spins and fully magnetized spins influxed during the section transit time(TR/slice number) are added, and result in ring, target, and small round patterns in the second section image.
Magnetic Resonance Imaging*

Aneurysm ; Bone Cysts ; Curettage ; Cytochrome P-450 CYP1A1 ; Female ; Humans ; Joints ; Mandible ; Maxilla ; Middle Aged ; Tooth ; Transplants

BACKGROUND: Keratinocyte-derived interleukin-1(IL-1)alpha is one of the key cytokines in initiation of cutaneous inflammation. Release of IL-1alpha from human keratinocytes may be induced by proinflammatory stimuli including ultraviolet B(UVB) irradiation, and subsequently, keratinocyte-derived IL-1alpha may exert numerous paracrine and autocrine effects. 1,25-dihydroxyvitamin D3(1,25(OH)2D3) is involved in the regulation of keratinocyte proliferation and differentiation and is also recognized to have immunoregulatory properties such as an antiinflammatory effect. OBJECTIVE: The purpose of this study was to investigate the in vitro effects of 1,25-(OH)2D3 on the production of IL-1alpha by UVB irradiation in cultured human keratinocyte cell line HaCaT cells. RESULTS: are summerized as follows; 1. The vialility of cultured HaCaT cells measured by MTS assay at 24 hours after UVB irradiation was significantly reduced at the doses of above 100 mJ/cm2 of UVB(p<0.05). 2. The secretion of IL-1alpha by HaCaT cells was significantly increased at the doses of above 30 mJ/cm2 of UVB(p<0.05). UVB irradiation could not influence on the secretion of IL-1beta by HaCaT cells. 3. At the concentrations of 10-8M and 10-6M of 1,25(OH)2D3, the production of IL-1alpha by HaCaT cells(48 hours after 100 mJ/cm2 UVB irradiation) was significantly inhibited in both culture supernatants and cell lysates(p<0.05). CONCLUSION: UVB irradiation increased the production of IL-1alpha by HaCaT cells and this stimulatory effect on the production of IL-1alpha induced by UVB irradiation was suppressed by 1,25-(OH)2D3. Calcipotriol(MC-903) had similar suppressive effect on the production of IL-1alpha induced by UVB irradiation in HaCaT cells to that of 1,25(OH)2D3.
Calcitriol* ; Cell Line* ; Cytokines ; Humans* ; Inflammation ; Interleukin-1alpha* ; Keratinocytes*

PURPOSE: To evaluate the utomated 1H magnetic resonance spectroscopy (1H-MRS) method for a routine clinical use, various regions of the normal human brain were examined for regional variations, the reproducibility, and thequality control of the spectral data. MATERIALS AND METHODS: Localized 1H-MRS was performed in a GE 1.5T SIGNAMRI/MRS system using the automated method(PROton brain Exam : PROBE). Six regions of the human brain from normal volunteers (N=25, age=23-65) were examined : Occipital gray matter, parietal white matter, frontal white matter, pons, cerebellum, and basal ganglia regions. STEAM was used as the localization method with the following parameters : TE=30 msec, TR=3.0 sec, AVG=48 AVG, NEX=2, Spectral Width (SW)=2500 Hz, Size (SI)=2048 points (2K),and the size of voxel=7-9 ml, The reproducibility and the quality control of the spectral date were evaluated. RESULTS: For the 6 regions, the regional variation by the spectral patterns and the metabolites ratios relative to creatine was well demonstrated. Rates of the auto prescan success and the percentages of obtaining the acceptable quality spectra were high in the parietal white matter, occipital gray matter, and basal gangliaregions, and low in the frontal white matter and pons regions. CONCLUSION: PROBE is a highly practical as well asreliable method to produce reproducible quality spectra that represent the regional metabolic variations in the human brain, PROBE can be used as a single spectroscopic exam or as an additional series to a routine brain MRI exam, which takes less than 10 minutes for acquiaition of one spectrum. In order to obtain good quality spectra, agood quality control scheme of the MR instrument is mandatory.
Basal Ganglia ; Brain ; Cerebellum ; Creatine ; Humans ; Magnetic Resonance Spectroscopy* ; Pons ; Quality Control ; Rabeprazole ; Spectrum Analysis ; Steam