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Biomedical subjects

I Uchida

Publications and source records attributed to I Uchida.

150 records · Page 9Linked to original sources
PubMedDate not supplied

Carboxyhemoglobin and methemoglobin levels in banked blood.

Carboxyhemoglobin and methemoglobin levels in 312 units of banked blood and their relationship to the duration of storage were determined. The carboxyhemoglobin level decreased as the storage time increased, and its mean was 1.4% +/- 2.0% (SD) with a range from 0% to 9.6%. Methemoglobin increased during storage, showing a mean level of 1.6% +/- 0.4% and a range from 0.5% to 4.2%. In a separate study, blood drawn from six volunteers who had smoked two cigarettes each was stored as banked blood for 21 days. The mean initial level of carboxyhemoglobin was 4.4% +/- 1.6%, and the mean half-life of carboxyhemoglobin was approximately 47 days. Methemoglobin increased from an initial 1.3% +/- 0.2% to 2.4% +/- 0.6% at the end of storage. The use of banked blood containing high levels of these abnormal hemoglobins could be a potential risk in critically ill patients.

Aged↗
PubMedDate not supplied

Strabismus surgery using the intraoperative adjustable suture method under anesthesia with propofol.

PURPOSE: To evaluate the feasibility and efficacy of using the intraoperative adjustable suture method with anesthesia induced by intravenously administered propofol for strabismus surgery. METHODS: Seven adult patients (mean age, 29.7 +/- 18.5 years) with different types of strabismus were enrolled in this study. All patients underwent full ophthalmological and general medical examinations before surgery. Surgery was performed after induction of anesthesia using intravenously administered propofol that was titrated to control consciousness. RESULTS: Arousal of consciousness was observed at approximately 2 minutes after discontinuation of the propofol infusion in each case, and the consciousness level was sufficient to allow accurate cover-uncover testing and intraoperative adjustment of sutures. Minor complications of nausea in three patients and vomiting in one patient were noted after surgery. CONCLUSIONS: Strabismus surgery using the adjustable suture method with propofol intravenous anesthesia appears to be safe and useful for the treatment of adult strabismus.

Adult↗
PubMedDate not supplied

The role of the GABA(A) receptor alpha1 subunit N-terminal extracellular domain in propofol potentiation of chloride current.

Propofol (2,6-diisopropylphenol), an intravenous general anesthetic in active clinical use today, potentiates the action of gamma-aminobutyric acid (GABA) at the type-A receptor and also directly induces current in the absence of GABA. We expressed different combinations of murine GABA(A) receptor alpha1, beta3 and gamma2 subunits in Xenopus oocytes to investigate the subunit dependence of propofol potentiation of pentobarbital-induced current. Pentobarbital induces current in all beta3-subunit-containing receptors, whereas current gating by GABA requires the presence of both alpha1 and beta3 subunits. Therefore, pentobarbital rather than GABA was used to induce current in order to separate the subunit dependence of current gating from the subunit dependence of potentiating action of propofol. alpha1beta3gamma2, alpha1beta3, beta3gamma2, or beta3 subunit combinations all responded to pentobarbital in a dose-dependent manner. True potentiation was defined as the current magnitude to simultaneous application of pentobarbital and propofol exceeding the additive responses to individual drug applications. A dose-dependent propofol potentiation of pentobarbital-induced current was observed in oocytes injected with alpha1beta3 or alpha1beta3gamma2 but not in beta3gamma2 or beta3 subunits, suggesting that the alpha1 subunit was necessary for this modulatory action of propofol. Further examination of the propofol potentiation in chimeras between the alpha1 and beta3 subunits showed that the extracellular amino-terminal half of the alpha1 subunit was sufficient to support propofol potentiation. The different requirements of the receptor structure for the agonistic (gating) and the potentiating actions suggest that these two actions of propofol are distinct processes mediated through its action at distinct sites.

Anesthetics, Intravenous↗
PubMedDate not supplied

Contribution of working memory to transient activation in human inferior prefrontal cortex during performance of the Wisconsin Card Sorting Test.

The Wisconsin Card Sorting Test (WCST) is the standard task paradigm to detect human frontal lobe dysfunction. In this test, subjects sort card stimuli with respect to one of three possible dimensions (color, form and number). These dimensions are changed intermittently, whereupon subjects are required to identify by trial and error a new correct dimension and flexibly shift cognitive set. We decomposed the cognitive requirements at the time of the dimensional changes of the WCST, using functional magnetic resonance imaging (fMRI). By explicitly informing subjects of a new correct dimension, the working memory load for the trial-and-error identification of the new dimension was removed. Event-related fMRI still revealed transient activation time-locked to the dimensional changes in areas in the posterior part of the inferior frontal sulci. However, the activation was significantly smaller than in the original WCST in which subjects had to use working memory to identify the new dimension by trial and error. Furthermore, these areas were found to spatially overlap the areas activated by a working memory task. These results suggest that working memory and set-shifting act cooperatively in the same areas of prefrontal cortex to adapt us to changing environments.

Adult↗