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Biomedical subjects

K Takeda

Publications and source records attributed to K Takeda.

At least 1,549 records · Page 86Linked to original sources

Serial P-31 MR spectroscopy after fructose infusion in patients with chronic hepatitis.

Serial changes in phosphorus metabolites after intravenous administration of fructose were compared between five healthy volunteers and five patients with chronic hepatitis by means of phosphorus-31 magnetic resonance (MR) spectroscopy. P-31 spectra were obtained every 5 minutes after intravenous drip infusion of 20% fructose at a dose of 0.5 g/kg of body weight. In the healthy volunteers, phosphomonoesters (PME) increased to 338% +/- 76% of the preadministration value at 15-20 minutes. Inorganic phosphate (Pi) was depleted in the first 15 minutes, then rebounded to 260% +/- 67% of the initial value. beta-adenosine triphosphate decreased to less than 50% of its initial value and then gradually recovered. In patients with chronic hepatitis, the increase of PME at 15-20 minutes (151% +/- 49% of the preadministration value) was significantly less than that in healthy volunteers (P less than .05). In addition, the rebound of Pi at 35-40 minutes (126% +/- 42%) was significantly less than that in healthy volunteers (P less than .05). In conclusion, P-31 MR spectroscopy with fructose administration is valuable in the functional evaluation of diffuse liver diseases.

Adenosine Triphosphate↗

Breath-hold MR measurements of blood flow velocity in internal mammary arteries and coronary artery bypass grafts.

Breath-hold velocity-encoded cine MR (VENC-MR) imaging is a feasible method for measuring phasic blood flow velocity in small vessels that move during respiration. The purposes of the current study are to compare breathhold VENC-MR measurements of flow velocities in the internal mammary arteries (IMA) with nonbreath-hold measurements and to characterize the systolic and diastolic flow velocity curves in a cardiac cycle in native IMA and IMA grafts. Flow velocity in 30 native IMA and 8 IMA grafts were evaluated with a breath-hold VENC-MR sequence with K-space segmentation and view-sharing reconstruction (TR/TE = 16/9 msec, VENC = 100 cm/s). In 10 native IMA, nonbreath-hold VENC-MR images were acquired as well for comparison. Breath-hold VENC-MR imaging showed significantly higher systolic and diastolic peak velocities in native IMA (43.1 cm/second +/- 15.0 and 10.0 cm/second +/- 4.8), in comparison to those of nonbreath-hold VENC-MR imaging (27.6 cm/second +/- 10.2 and 7.3 cm/second +/- 3.9, P < .05). The diastolic/systolic peak velocity ratio in the IMA grafts (.88 +/- .41) was significantly higher than that in native IMA (.24 +/- .08, P < .01). Interobserver variability in the flow velocity measurement was less than 4%. Breath-hold VENC-MR imaging demonstrated higher peak flow velocity in the IMA than nonbreath-hold VENC-MR imaging. This technique is a rapid and effective method for the noninvasive assessment of blood flow velocity in IMA grafts.

Adult↗

Comparison of breath-hold multishot echo-planar and respiratory triggered fast-spin-echo sequences for T2-weighted MRI of liver lesions.

The purpose of this study was to evaluate the usefulness of multishot echo-planar imaging in detecting liver tumors in comparison with respiratory triggered T2-weighted fast-spin-echo (FSE) imaging. Thirty-two patients with 70 focal liver lesions were imaged using a 1.5-T high speed MR imager. Eight-shot echo-planar images covering the whole liver were acquired during a single breath-hold period. FSE images were acquired with respiratory triggering in approximately 4 minutes. Lesion detectability and image quality of the two pulse sequences were analyzed qualitatively. Quantitative analysis was performed by means of signal-to-noise and tumor-liver contrast-to-noise analysis. Lesion detectability was comparable in both solid (86.3% vs 90.2%: .3 < P < .5) and nonsolid lesions (89.5% vs 100%: .3 < P < .5) between echo-planar and FSE images. Echo-planar imaging provided significantly reduced image artifact, better lesion conspicuity, and anatomic detail compared with FSE imaging. The signal-to-noise and contrast-to-noise ratios of echo-planar images were significantly higher than those of FSE images. Breath-hold eight-shot echo-planar imaging can be an alternative to T2-weighted FSE imaging because it can provide comparable image quality in a substantially decreased acquisition time.

Adult↗

Degradation of the rubber in truck tires by a strain of Nocardia.

A strip of tread compound cut from a truck tire was degraded only slightly when it was used as the sole growth substrate for a strain of Nocardia. On the contrary, its degradation was markedly enhanced by addition of a strip cut from a latex glove which the organism readily utilized as a growth substrate. When a glove strip was added, the biomass concentration in the experimental flask became more than 10-fold higher than the control without a glove strip and the colonization of the tire strip was significantly enhanced. After 8 weeks' cultivation, about 28% of the tire strip was disintegrated into very small black particles (mostly less than 30 microns in diameter) and the weight of the remaining unchanged portion of the strip was about 49% of the initial weight. Four kinds of truck tire treads were attacked in differing degrees by the organism under the same conditions. The treads containing more than 70 phr (parts per hundred of rubber) of natural rubber were considerably attacked, while those with a natural rubber content of less than 55 phr were attacked only slightly. The microbial activity against the rubber in the side wall of a truck tire was relatively high, but the inner liner was hardly attacked and the bead rubber not at all.

Biodegradation, Environmental↗

Anomalous insertion of the superior or the inferior vena cava into the right atrium.

Three cases with anomalous insertion of the superior or inferior vena cava into the right atrium are presented. One case was a 25-year-old healthy man with anomalous low insertion of the right superior vena cava into the right atrium. The remaining two cases were infants with complex cardiac anomalies showing anomalous high insertion of the inferior vena cava into the right atrium. The congenital anomalies of the connection between the superior and the inferior vena cava and the right atrium are rare. Angiographic and computed tomographic findings of these anomalies were reported.

Adult↗

Relief of mesenteric ischemia by Z-stent placement into the superior mesenteric artery compressed by the false lumen of an aortic dissection.

In a 58-year-old man acute aortic dissection compromised the origin of the superior mesenteric artery (SMA), resulting in mesenteric ischemia. After failed balloon angioplasty a Gianturco Z-stent was placed. The stenosis improved immediately, followed by resolution of the clinical signs of mesenteric ischemia. SMA flow was well preserved 1 year after stenting.

Acute Disease↗

Treatment of chronic type B aortic dissection with endovascular stent-graft placement.

A 74-year-old man with chronic aortic dissection was treated with an endovascular stent graft, fabricated from expanded polytetrafluoroethylene and a Z-stent. It was placed in the true lumen to close an entry tear. Closure was obtained immediately and thrombosis of the false lumen at the descending thoracic aorta was observed on computed tomography (CT) obtained 1 week later. No procedure-related complications developed. The patient is doing well with no adverse events including aortic rupture or aortic branch ischemia.

Aged↗

Bile acid metabolism in partially hepatectomized rats.

The bile flow and the bile acid secretion, calculated on liver weight basis, increased 12 H and 24 H after 60-70% hepatectomy and returned to the initial levels thereafter. The biliary phospholipid secretion much more increased than bile acids, but the cholesterol secretion decreased. Bile acid composition changed with an increase of the cholic acid group and a decrease of the chenodeoxycholic acid group in both bile and feces. These changes almost disappeared on Day 14. The pool size of bile acid decreased maximally on Day 4 to about 40% of the initial, but the distribution of bile acids in the enterohepatic circulation was not changed. The fecal cholesterol and coprostanol markedly decreased on Day 2 but gradually returned to the initial levels according to the recovery of diet intake. The fecal bile acids decreased on Day 2, increased on Day 4, and returned to the normal range after Day 7. In conclusion, the regenerating liver secretes more bile, bile acids and phospholipids, and less cholesterol than the normal liver. Cholic acid predominates in the bile acids. These changes restored to the initial levels by about one week after the operation.

Animals↗

The effects of anesthetics on the concentrations of cholecystokinin octapeptide sulfate-like immunoreactivity in rat brain regions.

Cholecystokinin octapeptide sulfate-like immunoreactivity (CCK-8S-LI) was determined by radioimmunoassay in rat brain areas following injections of pentobarbital, halothane and chloral hydrate. Time-dependent changes in the concentrations of CCK-8S-LI were different between pentobarbital and chloral hydrate in all brain regions studied. After pentobarbital injection, CCK-8S-Li peaked at 30-60 min in the frontal cortex, nucleus accumbens, striatum and substantia nigra; after chloral hydrate injection, CCK-8S-LI peaked at 120 min in the hypothalamus, nucleus accumbens and substantia nigra. Both anesthetics induced almost the same sleeping times. Halothane inhalation caused increases in the concentrations of CCK-8S-LI in the amygdala and hippocampus. In addition, following intracardial perfusion of saline for 30 min after pentobarbital anesthesia, the concentrations of CCK-8S-LI increased in the nucleus accumbens, and decreased in the frontal cortex. These results suggest that since different anesthetics cause different changes in CCK levels, anesthetics affect studies of these neurons.

Animals↗