Search PubMed⌕ Search

Biomedical subjects

Y Seo

Publications and source records attributed to Y Seo.

At least 163 records · Page 9Linked to original sources
PubMed1988

Phosphorus nuclear magnetic resonance in isolated perfused rat pancreas.

Phosphorus nuclear magnetic resonance spectroscopy was applied to measure phosphorus energy metabolites in isolated perfused rat pancreas. The gland was perfused with a modified Krebs-Henseleit solution at room temperature (25 degrees C). 31P resonances of creatine phosphate (PCr), ATP, ADP, inorganic phosphate (Pi), and phosphomonoesters (PMEs) were observed in all the preparations of pancreas. In different individual preparations, the resonance of PCr varied, but those of ATP were almost the same. The initial levels of PCr and ATP in individual preparations, however, remained almost unchanged during perfusion with the standard solution for 2 h. When the perfusion was stopped, the levels of ATP and PCr decreased, while the levels of PME and Pi increased. At that time, the Pi resonance shifted to a higher magnetic field, indicating that the tissue pH decreased. On reperfusion, the tissue levels of phosphorus compounds and the tissue pH were restored to their initial resting levels. Continuous infusion of 0.1 microM acetylcholine caused marked and sustained increases in the flow of pancreatic juice and protein output. During the stimulation the tissue levels of phosphorus compounds remained unchanged, while the tissue pH was decreased slightly (0.05 pH unit).

Adenine Nucleotides↗
PubMed1988

Dissociation of fluid secretion and energy supply in rat mandibular gland by high dose of ACh.

The effects of a high dose of acetylcholine (ACh) on oxygen consumption (VO2) and changes in phosphorus energy metabolites during secretion were studied in isolated perfused mandibular gland of rats at 24 degrees C. Sugar phosphates (SP), Pi, phosphocreatine (PCr), and ATP were identified by phosphorus-31 nuclear magnetic resonance spectroscopy. One micromole ACh induced a tachyphylactic secretory response, a persistently elevated VO2, and decreased PCr and ATP; 1 mM ACh caused an initial burst of secretion that was followed by suppression of secretion and a rapid increase in the VO2 to the same level as that with 1 microM ACh. These findings indicate a dissociation between secretion and VO2. During stimulation with 1 mM ACh, the level of PCr first decreased and then partially recovered, but the level of ATP continued to decrease and the levels of Pi and SP increased markedly. These findings suggest compartmentalization of creatine phosphokinase (CPK) systems and the possibility that a high concentration of ACh interferes with the transport of PCr between one CPK system near adenosinetriphosphatase and another system near mitochondria in acinar cells.

Acetylcholine↗
PubMed1988

[Coronary artery blood flow velocity non-invasively measured using a vessel-tracking pulsed Doppler system].

A newly-developed noninvasive method was used to measure left coronary blood flow during phantom experiments. Two techniques were used in which: (1) the sample position can always be set in a fluctuating vessel using a wall echo-tracking method with a phase-locked-loop, and (2) the Doppler reference signal was generated separately synchronous with the wall echo signal. These techniques were combined, using a commercially available pulsed Doppler apparatus (SSH-40B: Toshiba). Basic experiments were performed using a blood vessel phantom to verify the validity of these systems. Blood flow velocity in the fluctuating tube could be measured clearly using a vessel-tracking method. The blood flow velocity of the left anterior descending artery was measured in three normal subjects and in seven patients from the third intercostal space along the left sternal border. The velocity pattern was characterized by a crescendo-decrescendo shape in diastole. The peak velocity which appeared in diastole ranged from 19 to 69 cm/sec, with no difference by disease entity. However, in all cases, the blood flow velocity signals were marred by extraneous signals, making it impossible to measure blood flow velocity during systole. Further improvement of the system is mandatory in order to use this flowmeter clinically.

Adult↗
PubMed1988

[A case of colon cancer with pulmonary metastasis treated effectively by uracil futraful].

A 57-year-old female was admitted for advanced ascending colon cancer with a solitary pulmonary metastasis measuring 1.5 cm in diameter. As laparotomy revealed an absolute noncurable tumor of stage V (H0, p2, s2 n1 (+], palliative right hemicolectomy was performed. A pathological diagnosis of well differentiated adenocarcinoma was made postoperatively. A daily dose of 400 mg of UFT was given orally. After 8 months, plain chest film and tomography revealed a reduction in the size of the pulmonary metastasis to 1.0 cm in diameter. The metastatic lung tumor was controlled for a period of 1 year and 9 months. It was suggested that UFT was rather effective for pulmonary metastasis from colon cancer.

Adenocarcinoma↗
PubMed1987

Direct measurement of Na influx by 23Na NMR during secretion with acetylcholine in perfused rat mandibular gland.

Intracellular Na content (Nain) in the perfused rat mandibular gland was measured by using a 23Na NMR spectroscopy at 24 degrees C. An aqueous chemical shift reagent, dysprosium triethylenetetramine-N,N,N',N",N"'N"'-hexaacetic acid [Dy(TTHA)] was used in order to discriminate between the intracellular and the extracellular Na signal. The mandibular gland of rat was perfused arterially with a modified Krebs solution containing 10 mM Dy(TTHA). At rest, Nain was not changed by blocking the Na+/K+ ATPase with ouabain (1 mM) and atropine (3 microM), implying that, in the absence of stimulation, the spontaneous Na influx across the plasma membrane must have been negligibly small. Following onset of stimulation with acetylcholine (1 microM), Nain increased by 9.1 +/- 1.5 mmol/l intracellular fluid (mean +/- SEM, n = 13), and remained at this level during stimulation. In the initial phase of secretion (0-5 min), about 50 mmol/min/l intracellular fluid of Na was secreted into the luminal space (estimated from the secretory rate by assuming an isotonic primary secretion) but, in spite of the higher secretion rate, Nain increased only at an initial rate of 4.1 mmol/min/l intracellular fluid. During the steady phase of secretion (15-30 min) evoked by acetylcholine (1 microM), ouabain (1 mM) caused an increment of Nain of 44 +/- 8 mmol/l intracellular fluid (mean +/- SEM, n = 4). From the rate of Nain increment, the Na influx rate at the steady phase was estimated as 4.5 mmol/min/l intracellular fluid. These results suggest that the influx of Na is caused by stimulation with acetylcholine.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1987

High resolution 23Na-nuclear magnetic resonance study of stroke-prone spontaneously hypertensive rat erythrocytes.

The intracellular Na+ content of washed erythrocytes from stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar-Kyoto normotensive rats (WKY) was measured by a high resolution 23Na-nuclear magnetic resonance (NMR) technique using a non-permeant aqueous shift reagent, dysprosium triethylenetetramine hexaacetic acid, Dy(TTHA)3-. The initial intracellular Na+ of freshly isolated and washed erythrocytes was very low (approximately 5 mmol/l) and increased progressively with prolonged incubation in isotonic salt solution at 37 degrees C. There was no significant difference in the erythrocyte Na+ concentration between SHRSP and WKY over the entire period of measurement, nor was any difference detected in their osmotic fragility or total cellular volume, although the osmotic fragility decreased with incubation time. The high energy phosphate metabolites were also studied in the same erythrocytes by 31P-NMR. The level of intracellular ATP decreased with incubation at 37 degrees C but showed no difference between the SHRSP and WKY samples. Inclusion of 1 mmol/l ouabain in the incubation medium substantially retarded the breakdown of intracellular ATP and resulted in a concomitant increase in intracellular Na+. However, neither the ouabain-sensitive nor the ouabain-insensitive component of Na+ influx altered in SHRSP erythrocytes compared with WKY erythrocytes in paired experiments. Our results do not support the hypothesis that altered Na+ transport, resulting in an increase in erythrocyte Na+ concentration, is associated with spontaneous hypertension.

Animals↗
PubMed1987

31P NMR studies on the isolated perfused mandibular gland of the rat.

Phosphorus nuclear magnetic resonance (31P NMR) was used to study energy metabolism in the rat mandibular gland. The gland was isolated, perfused arterially and set in the NMR tube. At rest, 7 resonance peaks were observed and 6 peaks identified from low field as: 1) sugar phosphates (SP) and nucleotide monophosphate (NMP), 2) inorganic phosphate (Pi), 3) creatine phosphate (PCr), 4) gamma-nucleotide triphosphate (NTP) and beta-nucleotide diphosphate (NDP), 5) alpha-NTP, alpha-NDP, NAD+, and NADH, 6) an unknown peak, and 7) beta-NTP. From the results of high performance liquid chromatography (HPLC), NTP consisted mainly of ATP and GTP, and UTP was not detected. The tissue contents of ATP and GTP in the perfused gland were determined by HPLC as 1.86 +/- 0.03 and 0.37 +/- 0.01 mmol/kg wet tissue (S.E., n = 5). From 31P NMR and HPLC data, the tissue levels of creatine phosphate, ADP, and sugar phosphates were estimated as 3.3, 0.4, and 4.2 mmol/kg wet tissue, respectively. The cessation of perfusion decreased the tissue levels of PCr and ATP and increased those of Pi and SP. On the other hand, administration of acetylcholine (1 microM), which is an optimal dose for secretion, decreased PCr and increased Pi but did not change SP. The ATP was unchanged initially and slowly decreased to the lower level during sustained secretion. These findings suggest that a sustained secretion requires more energy from ATP hydrolysis rather than initial secretion.

Acetylcholine↗
PubMed1987

[Serum concentration of 5-FU and tegafur (FT-207) after administration of tegafur (FT-207) suppository with the colostomy].

Tegafur (FT-207) suppositories were administered at a rate of 750 mg via the artificial anus (ST Group) following surgery of rectal cancer. Comparative studies were conducted of changes in blood concentrations of 5-FU and tegafur at the time of initial administration and following one week of continuous use for the low-anterior resection cases (LA Group) and the rectal administration cases (RE Group). FT-207 concentration at initial administration was low in the ST group compared to those for both LA and RE groups which received anal administration of the drug, but only little changes were noted. Blood concentration one hour after administration was 11.1 micrograms/ml, elevated to 14.3 micrograms/ml at two hours, and remained at 10 micrograms/ml and above for six hours following administration. The ST group 5-FU concentrations at two, four and six hours after administration were significantly lower than those in the RE group but the changes were little. Blood concentrations were 0.015 microgram/ml at one hour after administration, 0.017 micrograms/ml at two hours and maintained virtually the same level thereafter. An effective concentration of 0.012 microgram/ml was maintained even at ten hours following administration. After one week of administration of the suppositories, the ST group showed the lowest concentration among three groups, but it was approximately double compared to the initial concentration; FT-207 showed nearly the same concentration in the LA group and 5-FU blood concentration was 0.025 microgram/ml at one hour after administration, reached to a maximum of 0.030 microgram/ml at two hours and maintained 0.020 microgram/ml and higher at ten hours. 5-FU concentration in the LA and RE groups after one week of continuous administration showed a dual-peaked pattern. No patient with an abnormal artificial anus was involved in this study. The artificial anus is thought to be an adequate and effective administration route of FT-207 suppositories.

Adult↗
PubMed1987

[Intraoperative radiotherapy].

Intraoperative radiotherapy, which delivers a large single dose of electrons to a tumor intraoperatively, is applied for locally advanced and/or difficult to cure malignancies which are rather difficult to treat by conventional external beams. Although this method was initially developed in Japan, increasing numbers of institutes have recently been working with IORT on a world-wide basis because of the increased availability of medical accelerators and the better results obtained. The malignancies for which IORT is indicated are cancers of the stomach, liver, biliary tract, pancreas, colo-rectum, urinary bladder, prostate and uterus, which are surrounded by normal tissues or organs with low tolerance doses, and also recurrent or difficult to cure malignancies of the brain, lung, mediastinum, bone and soft tissues are becoming candidates for IORT treatment.

Female↗
PubMed1986

Continuous measurements of Na, Li, and Cl in the perfused salivary gland by use of NMR.

The present study was undertaken to measure tissue contents of Na, Li, and Cl non-invasively in the isolated perfused organ by nuclear magnetic resonance (NMR) using a broadband tunable probe. The NMR signals of 23Na, 7Li, and 35Cl from the isolated perfused rat mandibular gland were collected continuously and each spectrum was obtained for every 15 or 20 s. The Na concentration in the perfusate was varied by replacement with Li, and the resulting changes were monitored by measuring the signal intensities of the electrolytes. The time constant for Na exchange was slower following complete removal of extracellular Na than following its half replacement, suggesting that the Na extrusion by Na+/K+ ATPase was reduced by lowering the extracellular Na level. The time constant for Li exchange was slower than that for Na exchange. The level of Cl was nearly constant during experiment, except for a very slow increase in Cl, possibly resulting from increasing edema and/or intracellular Li storage.

Animals↗
PubMed1985

31P-NMR study of dog submandibular gland in vivo and in vitro using the topical magnetic resonance.

The topical magnetic resonance (TMR) was used to study the phosphorous metabolism of a dog's submandibular gland during acetylcholine stimulation. The experiments were carried out under two conditions. One was a normal blood supply (in vivo) and the other was vascular perfusion with the artificial perfusate (in vitro). The levels of phosphorous compounds in the gland were obtained for 31P-NMR spectra of the TMR. The saliva was secreted in the both conditions, though the salivary flow under the in vivo condition was higher than in vitro. During salivary secretion, only the levels of creatine phosphate decreased under in vivo condition, while the levels of creatine phosphate and ATP decreased and the levels of inorganic phosphate increased in in vitro cases. It was concluded that the decrement of creatine phosphate during the salivary secretion indicates the acceleration of the energy metabolism in the submandibular gland.

Acetylcholine↗
PubMed1985

[Radiotherapy of pancreatic carcinoma].

During the 10-year period between 1974 and 1984, we treated 34 pancreatic carcinomas by radiotherapy as follows: Eight by intraoperative radiotherapy (IOR), five by external radiotherapy (ERT), and 21 by IOR in combination with ERT. The mean survival time of the eight patients treated by IOR was 5.6 months, and that of the 21 receiving the combination therapy 7.2 months. Although it is not statistically significant, patients treated by the combined regimen survived longer than those treated by IOR alone.

Aged↗
PubMed1984

Effects of extracellular pH on lactate efflux from frog sartorius muscle.

The isolated sartorius muscle of frog was stimulated under an anaerobic condition, and intracellular lactate concentration and intracellular pH was determined sequentially by 1H-nuclear magnetic resonance, and the efflux of lactate was measured by an enzymatic method on the incubation media with different pH levels. The lactate efflux was shown to increase in proportion to the concentration difference of lactate across the membrane up to 25 mmol X l H2O-1, and the permeability of the membrane to lactate increased with the increment of extracellular pH. H+ efflux was determined from pH change and the buffer capacity of incubation medium. The efflux of H+ rose approximately linearly with the efflux of lactate up to approximately 70 mumol X min-1 X l H2O-1, and the relationship then revealed a clear leveling off. From these results the efflux of lactate was analyzed in terms of a predominantly nonionic or a predominantly ionic efflux mechanism. Analysis showed that the mechanism of efflux was in both the ionic and nonionic form.

Anaerobiosis↗