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Biomedical subjects

E Fukushima

Publications and source records attributed to E Fukushima.

28 records · Page 2Linked to original sources
PubMed1986

A new method for flow velocity measurement: frequency encoded NMR.

We demonstrate a new rapid NMR method to measure the average velocity and the velocity distribution of a flowing fluid. We use a truncated Carr-Purcel-Meiboom-Gill pulse sequence, pi/2-T-pi-2T-pi-T-echo, in the presence of a static magnetic field gradient. The pi/2 pulse is selective and tags a narrow slice of nuclei. The second echo from the tagged nuclei is Fourier transformed after the nuclei have evolved for a time 4T to give the velocity distribution modified by the initial slice selection profile. In this way, average velocities up to 54 cm/s were measured for water flowing in a plastic tube with either a plug or a developed velocity distribution. Each measurement required about 20 ms but this could be reduced with larger field gradients. Thus, this method is fast enough to apply to such problems as measuring pulsatile flow in arteries.

Animals↗
PubMed1984

Comparison of the first-pass metabolism of ethenzamide and salicylamide in rats.

The first-pass metabolism of ethenzamide (ETB), which is considered to be a pro-drug of salicylamide (SAM), was studied in rats in order to compare with that of SAM. The extent of first-pass metabolism after oral ETB estimated by oral and intravenous administration was as much as 82% and remaining 18% ETB entered into systemic circulation. Further, it has been confirmed that the first-pass metabolism of ETB is not due to the intestine but entirely due to the liver in which de-ethylation to SAM occurred at first, followed by exclusive conjugation with sulfuric acid and little SAM enters into systemic circulation. On the other hand, it was previously demonstrated in rats that per se administered SAM is subjected to first-pass metabolism both in the gut and liver as much as about 60% and the remaining 40% entered the systemic circulation. Thus, the behavior of SAM is considerably different depending upon whether it is per se administered or formed from ETB through metabolism. The fact that little SAM appears in the systemic circulation after oral administration of ETB suggests that the pharmacological activity of ETB comes from its own attributes but not from SAM.

Administration, Oral↗
PubMed1982

[Luteotropic effect of human chorionic gonadotropin on human corpus luteum in early gestation (author's transl)].

To study the luteotropic effect of human chorionic gonadotropin (hCG) on human corpus luteum in early gestation, serum pregnenolone, 17 alpha OH-pregnenolone, dehydroepiandrosterone, progesterone, 17 alpha OH-progesterone, androstenedione, 20 alpha-dihydroprogesterone and estradiol levels in both ovarian and peripheral venous blood measured by RIA before and after administration of hCG. Seven patients selected for this experiment were 6 to 16 weeks of gestation complicated with fibromyoma. On hysterectomy, 1,000 or 2,000 I.U. of hCG was directly injected into the ovary with corpus luteum to the patients of 6, 12 and 16 weeks of gestation, or 100,000 I.U. of hCG was infused intravenously to the patients of 9 and 14 weeks of gestation. Before 12 weeks of gestation, all free steroid levels except for conjugated steroids in ovarian vein increased promptly 1.8 to 8.9 fold as compared with control levels and stayed high levels for 25 to 60 minutes after administration of hCG. However no marked alteration of these steroids was observed in peripheral vein. In cases studied after 14 weeks of gestation, no marked change of steroid levels in ovarian vein was noticed, while a moderate increase of hCG was observed. These results demonstrated that hCG stimulates the steroidogenesis of corpus luteum in early pregnancy. It was demonstrated that extremely high doses of hCG was required to stimulate steroidogenesis corpus in luteum gravidarum of early gestation.

Chorionic Gonadotropin↗
PubMedDate not supplied

Characterization of partially sintered ceramic powder compacts using fluorinated gas NMR imaging.

We use nuclear magnetic resonance (NMR) imaging of C2F6 gas to characterize porosity, mean pore size, and permeability of partially sintered ceramic (Y-TZP Yttria-stabilized tetragonal-zirconia polycrystal) samples. Conventional measurements of these parameters gave porosity values from 0.18 to 0.4, mean pore sizes from 10 nm to 40 nm, and permeability from 4 nm(2) to 25 nm(2). The NMR methods are based on relaxation time measurements (T(1)) and the time dependent diffusion coefficient D(Delta). The relaxation time of C2F6 gas is longer in pores than in bulk gas and it increases as the pore sizes decrease. NMR yielded accurate porosity values after correcting for surface adsorption effects. A model for T(1) dependence on pore size that accounts for collisions between gas molecules and walls as well as surface adsorption effects is proposed. The model fits the experimental data well. Finally, the long time limit of D(Delta)/D(o), where D(o) is the bulk gas diffusion coefficient is useful for measuring tortuosity, while the short time limit was not achieved experimentally and could not be used for calculating surface-area to volume (S/V) ratios.

Ceramics↗
PubMedDate not supplied

[Role of anorectal manometry in the differential diagnosis of chronic constipation in children]

OBJECTIVES: 1. To evaluate the role of anorectal manometry in recognizing patients with histological abnormalities of the myenteric plexus as the cause of chronic constipation. 2. To correlate clinical features with the etiology of the constipation.METHODS: The etiology of the constipation was identified retrospectively from the medical records of 57 patients submitted to anorectal manometry. The test was performed in the Pediatric Gastroenterology Laboratory of the University Hospital of the State University of Campinas Medical School. The procedure was performed using a single-balloon system in which a water-perfused pressure transducer was interfaced with a polygraph and displayed on a computer screen. Manometry was performed in patients who, after 6 to 23 months of intense medical treatment using osmotic laxatives and dietary fibres (20 g/d), continued to develop fecal impaction and/or needed evacuatory enema. Regularization of bowel movements during at least 24 months follow-up or the visualization of abnormalities in myenteric plexus in rectal biopsy were used as reference points for the definitive diagnosis.RESULTS: Rectoanal reflex was present in 44 of the 57 patients (77%). Thirteen patients with a negative reflex underwent rectal biopsy which showed abnormalities of the ganglion cells in 10. Subsequent manometry performed on those three patients revealed a normal rectoanal reflex. Sensitivity, specificity, positive and negative predictive values of the manometric test were 1.0, 0.94, 0.77 and 1.0, respectively.CONCLUSIONS: Anorectal manometry is a diagnostic technique with very small possibility of error in differential diagnosis between constipation of a chronic functional nature and that which is secondary to ganglion cell abnormalities.

Journal Article↗