Safety problems of dB/dt associated with echo planar imaging.
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Brain↗
Biomedical subjects
Y Seo
Publications and source records attributed to Y Seo.
Partial hepatic resection under intermittent hepatic inflow occlusion in patients with chronic liver disease.
A partial hepatic resection was performed in 13 patients with chronic liver disease using intermittent hepatic inflow occlusion. Eleven patients had liver cirrhosis and two had chronic hepatitis. Seven patients were classified as Child's grade A and six as Child's grade B before operation. Dissection of the hepatic parenchyma was performed during intermittent inflow occlusion. The time of clamping and declamping was 10-20 min and 5-8 min, respectively. Postoperative data on liver function showed recovery to preoperative levels by about 10 days after operation. There were no life-threatening complications. These results indicate that intermittent hepatic inflow occlusion can be achieved easily and safely to allow non-anatomical resection in patients with chronic liver disease.
Aged↗
Glycyrrhizin and glycyrrhetinic acid determination from formalin-fixed tissue.
Glycyrrhetinic acid (GA), the main metabolic product of glycyrrhizin (GLY), could be detected in formalin-fixed tissue from a man who died 6 hours after therapeutic administration of a GLY-containing agent. GA was extracted from homogenized formalin-fixed liver tissue and 3 ng GA/g could be detected by HPLC. The extraction from formalin-fixed liver tissue gave the same retention time peak as the GLY control. GA could also be detected by mass spectrometry in the blood sample. This confirms that the man had received a GLY-containing agent for therapeutic use prior to his death and that GA can be determined from formalin-fixed tissue.
Anti-Inflammatory Agents↗
Osmotically inactive space during hyperosmotic stress in the perfused submandibular gland of the rat.
Cell volume changes were measured by an impedance method during hyperosmotic stress in the perfused rat submandibular gland. When the perfusate osmolarity was raised to 484 mosmol, the cell volume decreased and remained at a plateau level (79%). The decrease was smaller than expected from the extracellular fluid osmolarity change. Furthermore, the potassium content of the gland increased by 7% during the hyperosmotic stress. These results suggest that the cell volume changes observed during hyperosmotic stress are affected by the existence of an osmotically inactive space and by an increase in the intracellular solute content.
Animals↗
A sandwich enzyme immunoassay for liver-specific antigen and its forensic evaluation.
We attempted to develop a method for the determination of liver injuries, using a liver-specific antigen as a marker. The liver-specific antigen (LSA) was purified from the human liver and the antibody to the human LSA only reacted with the liver extract using the immuno-dot-blotting technique. Depending on the immunohistochemical study, the LSA was found to be located within the cytoplasm of hepatocytes. A sensitive and specific sandwich enzyme immunoassay was then developed for the measurement of LSA. The detection limit of human LSA was 1 fmol/tube (52 pg/tube) and this assay was not affected by hemolysis. The LSA levels in serum and blood from healthy subjects were distributed within a range below the detection limit. The LSA levels in the blood from cadavers whose livers had been damaged, were markedly elevated in comparison with the normal levels found in other cadavers (10-140 fold). No cross-reaction was observed with the liver extracts from several species (mouse, rat, guinea pig and rabbit). These results suggest that the measurement of LSA levels in blood will become a useful marker for the detection of liver injury.
Biomarkers↗
Monitoring of intracellular ammonium in perfused rat salivary gland by nitrogen-14 nuclear magnetic resonance spectroscopy.
We have observed the changes in the intracellular ammonium (NH4+) content and the intracellular pH during administration of 20 mM NH4Cl (the ammonium pulse experiment) using nitrogen-14 and phosphorus-31 nuclear magnetic resonance spectroscopy (14N and 31P NMR) at 8.45 T. In the isolated perfused rat mandibular salivary gland, resonances of trimethylamines (-328 p.p.m.) and betaine (-329 p.p.m. from the resonance of NO3-) were detected. A chemical shift reagent, 10 mM of dysprosium triethylenetetramine-N,N,N',N",N"',N"'-hexaacetic acid (Dy(TTHA], was used to discriminate between the resonances from the extracellular NH4+ (-352 p.p.m.) and the intracellular NH4+ (-355 p.p.m.). During the NH4Cl application, the intracellular NH4+ content [( NH4+]i) increased quickly to ca. 50 mmol per litre intracellular fluid (ICF), then increased gradually to ca. 70 mmol per litre ICF. The intracellular pH (pHi), calculated from the 31P chemical shift of inorganic phosphate, increased transiently by 0.5 pH units and then decreased gradually in spite of the high level of [NH4+]i. The initial increase of [NH4+]i, which was observed by 14N NMR, was larger than that calculated from the intracellular pH on an assumption of a non-ionic diffusion process for ammonia. These results suggest a possibility of influx of NH4+, and also suggest an activation of cellular buffering mechanism that extrudes the excess bases from the cells.
Ammonia↗
NMR relaxation characteristics of rubidium-87 in perfused rat salivary glands.
Rubidium is a good substitute for potassium in many biological systems, and it has been suggested that rubidium-87 nuclear magnetic resonance (87Rb-NMR) spectroscopy could be used to measure K+ fluxes across membranes in intact tissues. To evaluate this possibility, isolated rat mandibular salivary glands were perfused with solutions containing Rb+ in place of K+. The 87Rb signals arising from the intra- and extracellular compartments were first separated by spectral subtraction and then subjected to line-shape analysis. The narrow extracellular signal was a single Lorentzian (line-width 156 Hz), whereas the broader intracellular signal consisted of two Lorentzian components (ca. 530 and 3080 Hz). Double-quantum filtering of the 87Rb signal from the glands revealed two components of transverse relaxation in antiphase (rate constants 1.8 and 13.3 ms-1), showing the probable involvement of quadrupolar interactions in the relaxation of intracellular Rb+. We conclude, therefore, that both line-shape analysis and double-quantum filtering could provide a basis for the measurement of unidirectional K+ fluxes in intact tissues.
Animals↗
Validation of a toxicity testing model by evaluating oxygen supply and energy state in the isolated perfused rat kidney. Single-pass preparation without albumin.
Validation of a toxicity testing model concerning energy metabolism was attempted by evaluating the oxygen supply and energy state in an isolated perfused rat kidney of single-pass preparation without albumin. Perfusion was performed at a temperature of 31 degrees C, flow rate of 11.0 mL/g/min, and pressure of 81-104 mmHg. The perfusate was saturated with 95% O2/5% CO2. After preperfusion for 30 min, the redox states of cytochrome aa3 and c and pyridine nucleotides (PN) in the perfused kidney were measured to be stable for 90 min by a scanning reflectance spectrophotometry and surface fluorometry, respectively. During the same period, the contents of ATP and inorganic phosphate (Pi) in the perfused kidney were also measured to be stable by 31P-NMR spectroscopy. The oxygen supply to the cell was more than the amount required for the basal metabolism of the cell. For assessment of the effects of chemical agents on the renal cell metabolism, this preparation of the perfused rat kidney was considered to have several advantages, despite some of its inherent limitations in the function of the kidney.
Adenosine Triphosphate↗
High-resolution magnetic resonance imaging of the human temporal bone.
A magnetic resonance imaging (MRI) system (Hitachi, Naka, Japan) with a superconductive magnet running at 2.11 T was used to obtain 2-mm-thick slices of fixed, decalcified and celloidin-embedded human temporal bone. The temporal bone was then sectioned and stained for routine histological evaluation. Both the MR images and the histological sections were in the mid-modiolar slice plane, and comparable images and sections were analyzed to confirm the identity of the inner-ear structures visualized on the MR images. The cochlear duct, scala tympani, scala vestibuli and basement membrane of all three cochlear turns were clearly imaged on MRI. In addition, the vestibule and three semicircular ducts were also clearly seen. This study raises the possibility of some day using MRI for the diagnosis of inner-ear diseases.
Basement Membrane↗
Dose effects of cholecystokinin and acetylcholine on phosphorus compounds and secretory responses in isolated perfused pancreas of rat.
Phosphorus nuclear magnetic resonance (31P NMR) spectroscopy was used to study energy supply for protein secretion in the isolated perfused rat pancreas. Stimulation with cholecystokinin (CCK-8) increased fluid secretion and protein output. With 10pM of CCK-8, the tissue contents of ATP, inorganic phosphate (Pi), and creatine phosphate (PCr) remained unchanged. With 100pM of CCK-8, which induced the maximum response in fluid secretion and protein output, Pi increased slightly, ATP and PCr remained almost unchanged. A high dose of CCK-8 (1 nM) suppressed the fluid and protein secretory rates, decreased ATP, and increased Pi significantly, but PCr showed a tendency of increase. Significant changes in ATP and Pi occurred on withdrawal of CCK-8 (1 nM), suggesting activation of ATP hydrolysis for recovery from secretory suppression. During stimulation with 0.1, 0.3, and 3.0 microM of acetylcholine, the similar dose-dependent response was observed in the secretion and the phosphorus metabolism. The present study demonstrated that cytosolic energy metabolism for secretory responses in the pancreas is low and the Lohmann reaction showed less contribution than in the salivary gland. The findings suggest that the energy supply for protein secretion may be cytosolic diffusion of ATP and that the Lohmann reaction system may contribute to synthesis and storing of secretory protein at resting state.
Acetylcholine↗
Isolation and characterization of liver-specific antigen.
The purpose of this work is to develop a method to determine liver injuries using liver-specific substances. Initially, the liver-specific antigen (LSA) was purified from the human liver. The human LSA found in the Sephadex G-100 gel filtration first peak, has been isolated and characterized from normal human liver water-soluble proteins. Purification of LSA was carried out by consecutive gel filtration, ammonium sulfate precipitation, and anion and cation ion exchange chromatography, while simultaneously monitoring its reactivity using the antibody against the first peak fraction of the human liver extract through Sephadex G-100 after absorption with serum and kidney extract. This antigen was found to have a single band in SDS electrophoresis (PAGE) and the M.W. of approximately 52 KD. By IEF electrophoresis, the isoelectric point of some constituents were found to be pI 5.8-5.9. In addition, the antibody to this antigen was examined for organ specificity using the immunoblotting technique against the human kidney, lung, heart, spleen, pancreas, skeletal muscle, brain extracts and serum, respectively. The immunogenicity and characteristics of this antigen were found to be different from other specific antigens in the liver, which have been previously reported.
Forensic Medicine↗
A method of measuring the peak flow rate and the regurgitant volume of regurgitation based on the characteristics of turbulent free jets.
The issuing flow rate of a jet, Q0, is given by Q0 = U0A, where U0 is the issuing velocity of the jet and A is the cross-sectional area of the orifice. However, measurement of A of a regurgitant jet in the cardiovascular system is difficult. On the assumption that the jet is 'free' and turbulent, the following relations apply between the diameter of the orifice D, the length of the core region of the jet L, the centerline velocity of the jet Uc(chi) at an arbitrary distance chi(greater than L) from the orifice, and U0:L = 6.8D and Uc(chi)/U0 = L/chi. From these equations we obtain Q0 = 0.017 (chi Uc(chi))2/U0. Pulsatile jets issuing into an aqueous glycerol bath through orifices with various diameters were studied. U0, chi and Uc(chi) were measured with a color Doppler system. There was a good linear correlation between the peak flow rates estimated from the above equation and those measured with a flowmeter irrespective of the diameter of orifices (y = 0.93 chi + 3.8, r = 0.95, SEE = 6.6 ml/s). Assuming that the flow rate waveform is similar to the issuing velocity waveform, we estimated the issuing volume per stroke by integrating the issuing velocity. There was a good linear correlation between the estimated issuing volume and the known stroke volume of the pump (y = 1.0 chi + 2.6, r = 0.92, SEE = 2.8 ml).
Blood Flow Velocity↗
Purification of the pyocin S2 complex from Pseudomonas aeruginosa PAO1: analysis of DNase activity.
Pyocin S2 purified from mitomycin C-induced lysates of Pseudomonas aeruginosa strain PAO1 has been shown to consist of a complex of two proteins. Further analysis of the purified S2 complex revealed that the 74 kd S2 pyocin demonstrates DNase activity which can be blocked by S2-specific antisera. Chromosomal DNA from pyocin sensitive cells treated with the pyocin S2 complex in vitro did not show any degradation, suggesting that the 10 kd protein inhibits the DNase activity of the S2 protein. These results suggest an alternative mechanism for the toxicity associated with the S2 pyocin.
Antibodies, Monoclonal↗
Measurement of intracellular Na in the rat salivary gland: a 23Na-NMR study using double quantum filtering.
23Na in the prefused rat mandibular salivary gland was measured by spin-echo double quantum filter 23Na-NMR spectroscopy at 8.45 T. Resonances due to the intracellular 23Na and the interstitial 23Na were observed in the perfused gland at 25 degrees C. The resonance due to intracellular 23Na consisted of two Lorentzian signals stemming from the [1/2 mean value of -1/2[ coherence (sharp resonance) and the [-1/2 mean value of -3/2[ and [3/2 mean value of 1/2[ coherences (broad resonance). The transverse relaxation rate constant corresponding to the [1/2 mean value of -1/2[ coherence was 95 +/- 4 s-1 and that corresponding to the [-1/2 mean value of -3/2[ and [3/2 mean value of 1/2[ coherences was 1360 +/- 75 s-1 (mean +/- S.E., n = 5). The resonance due to the interstitial 32Na had longer relaxation rate constants, and disappeared upon administration of dysprosium triethylenetetramine-N,N',N",N",N"'-hexaacetic acid.
Acetylcholine↗
NMR characteristics of intracellular K in the rat salivary gland: a 39K NMR study using double-quantum filtering.
Intracellular K of the perfused rat mandibular salivary gland was measured by 39K NMR spectroscopy at 8.45 T. Multiple-quantum NMR arising from multiple-exponential decay was used to eliminate the resonance due to extracellular K in the perfused gland at 25 degrees C. The resonance due to intracellular K consisted of two Lorentzian signals stemming from the [spin 1/2 to -1/2] coherence (sharp resonance) and the [spin -1/2 to -3/2], [spin 3/2 to 1/2] coherences (broad resonance). The transverse relaxation time (T2) corresponding to the [spin 1/2 to -1/2] coherence was ca. 2.5 ms, and that corresponding to the [spin -1/2 to -3/2], [spin 3/2 to 1/2] coherences was ca. 0.4 ms. The relaxation time of the double-quantum coherence of rank 3 (originating from product operators like Ix2Iz) was determined to be ca. 0.2 ms. These results suggest the possibility of the presence of a single homogeneous population of intracellular K with a correlation time of ca. 2.5 x 10(-8) s and a quadrupolar coupling constant of ca. 1.4 MHz.
Animals↗
Sodium-23 MR imaging of the kidney in guinea pig at 2.1 T, following arterial, venous, and ureteral ligation.
In vivo 23Na magnetic resonance images of guinea pig kidney were obtained at 2.1 T using a spin-echo sequence with an echo time of 19 ms. The intact kidney showed a very strong signal intensity in the sodium image. The signal intensity of the kidney decreased to 55% after ligation of the renal artery together with the vein and the ureter. The total sodium content in the excised kidney after arterial occlusion, measured by flame photometry, was 24% higher than that in the intact kidney. The transverse relaxation time (T2) of the extracellular sodium in the isolated kidney decreased to one-third of that in the intact kidney. This shortening of T2 may be partly responsible for the decrease in the 23Na signal intensity from the kidney after arterial occlusion.
Animals↗
Energetic recovery from hypothermic preservation in the rat liver.
Changes in energy metabolism induced by norepinephrine were observed in liver perfused immediately after dissection and in liver stored in Euro-Collins solution at 0 degrees C for 24 hr. Oxygen consumption, glucose output, ATP content, and tissue pH were measured in isolated perfused rat liver at 37 degrees C. In fresh liver, a two-fold increase in glucose output and oxygen consumption was induced by norepinephrine (1 microM), while changes in ATP content and tissue pH were minimal. In stored liver, the cumulative increments in glucose output and oxygen consumption induced by norepinephrine were 30 and 27% those of fresh liver, respectively. ATP content of the unstimulated liver was 76% that of the fresh liver, then decreased to 50% during stimulation. A transient decrease in tissue pH (0.14 pH unit) was significant compared with that of fresh liver. These results suggest that norepinephrine stimulation is useful for assessing energetic and functional recovery of reperfused liver following hypothermic storage.
Adenosine Triphosphate↗
Adenosine triphosphate compartmentation in the rat heart: a 31P spin-lattice relaxation study.
Longitudinal relaxation times (T1) of phosphorus compounds in the perfused rat heart and erythrocytes were measured using the 31P Driven-Equilibrium Single-Pulse Observation of T1 relaxation (DESPOT) method at 33 degrees C. Both creatine phosphate in the heart and the three phosphate groups of adenosine triphosphate (ATP) in erythrocytes showed single-exponential relaxation. The three phosphate groups of ATP in the heart, however, had two T1 components. The T1 values of the short and the long T1 components of the beta-phosphate of ATP were ca. 0.4 and 14 s, respectively. The fraction with the long T1 represented ca. 30% of the total ATP content. These results suggested that there were two major pools of intracellular ATP in the rat heart which could be determined by 31P NMR spectroscopy.
Adenosine Triphosphate↗