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Biomedical subjects

T Hirai

Publications and source records attributed to T Hirai.

At least 109 records · Page 6Linked to original sources

Effects of slow tempo exercise on respiration, heart rate, and mood state.

The purpose of this study was to investigate psychophysiologic responses to slow movement tempo exercise in three experiments. Exps. 1 and 2 were designed to compare slow with preferred movement tempos chosen freely by the subjects. The task movements in Exp. 1 were repetitive Arm Swinging, Stepping, and Body Swaying, performed by 14 female undergraduate students, while in Exp. 2, Body Swaying and Arm Winding were performed by 10 female undergraduate students and 13 boys and girls junior high school students. Respiration, heart rate, and scores on the State-Trait Anxiety Inventory were measured. Analysis showed respiration rates were lower during slow tempo conditions than preferred conditions. Exp. 3 was designed to compare very slow with slow movement tempos, using a Tai Chi-type of movement performed by 6 female undergraduate students. The subjects were required to synchronize the task movement with auditory stimuli, during which respiration and heart rate were measured, and a UWIST Mood-Adjective Checklist was utilized. Under the very slow movement conditions, Energetic Arousal scores were lower than those for the slow movement and the variation of respiration between rest and task conditions corresponded inversely with the Tense Arousal scores. Together, our results suggest that slow tempo exercise does not increase physiological or psychological arousal.

Adolescent↗

Evaluation of dural sinus invasion and extension of extra-axial intracranial tumors. The advantages of a high-resolution postcontrast 3-D gradient-echo technique.

OBJECTIVE: To assess the usefulness of a postcontrast 3-D Fourier transform (3DFT) gradient-echo (GRE) technique in dural sinus invasion and extension of extraaxial intracranial tumors in comparison with a conventional spin-echo (SE) technique. MATERIAL AND METHODS: Fourteen consecutive patients with 15 extra-axial tumors in contiguity with the dural sinus, including 14 meningiomas and 1 adenoid cystic carcinoma, underwent postcontrast T1-weighted SE and GRE MR studies. Detectability of dural sinus invasion and extension was evaluated using two sequences by two neuroradiologists in a blinded manner and compared with surgical results. Quantitative analysis was also performed to calculate the contrast-to-noise ratio (CNR) between lesion and dural sinus on SE and GRE images. The data were analyzed statistically using a matched paired t-test. RESULTS: In the qualitative evaluation, the detectability of dural sinus invasion in 3DFT-GRE images was superior to that using SE images. The mean CNR for all lesions was 3.86 on SE images and 5.63 on 3DFT-GRE images (p = 0.03). CONCLUSION: For evaluation of dural sinus invasion and the extension of extra-axial tumors, postcontrast 3DFT-GRE MR images were superior to conventional SE images.

Adult↗

[Multiple nodular pulmonary amyloidosis with multiple bullae].

We report a case of multiple nodular amyloidosis accompanied by multiple emphysematous bullae. The patient was a 72-year-old nonsmoking woman who presented with chronic cough and had a history of pneumothorax. Chest computed tomography disclosed multiple nodules up to 1 cm in diameter, and multiple small emphysematous bullae predominantly distributed in the middle and lower lung fields. Left lung biopsy was performed under thoracoscopy. The nodules were histopathologically diagnosed as amyloidoma. The mechanism of the accompanying bullae formation was also considered.

Aged↗

[Abnormal Q wave in the right precordial leads unmasked during right bundle branch block in a patient with anteroseptal myocardial infarction: a case report].

Electrocardiography in a 77-year-old woman showed small R waves in leads V1-V3 3 hours after the onset of acute anteroseptal myocardial infarction. Abnormal Q waves appeared in leads V1-V3 only during intermittent right bundle branch block. The normal septal force disappeared after transmural septal infarction and a small force of right ventricle origin became apparent as a small R wave in V1. Right bundle branch block delayed activation of right ventricle, and thereby deleted the initial R wave and unmasked the Q wave of the septal infarction. Appearance of a Q wave in leads V1-V3 with right bundle branch block should not be assumed to reflect the extension of myocardial infarction.

Aged↗

[The clinical effect of low-dose FP (5-FU + low-dose CDDP) in patients with far advanced gastric cancer, and their quality of life].

Low-dose FP therapy was carried out in 30 patients with far advanced gastric cancer and assessed according to anti-tumor effect and quality of life (QOL). This therapy consisted of CDDP (3.5-7 mg/m2/day infused on Days 1-5 every week) and continuous infusion of 5-FU (250 mg/m2/day for 28 days). A partial response was observed in 15 cases, so the overall response rate was 50%. The response rates with stomach and lymph node cancers were higher than those of other organs (64.3% and 55.6%). Patients without peritoneal dissemination, with good performance status (PS) (0, 1) and differentiated histologic type showed a significantly higher response rate than patients with peritoneal dissemination, poor PS (2, 3, 4) and undifferentiated histologic type (p = 0.0034, 0.0253, 0.0080). No side effects (> or = WHO grade 3) were observed. The QOL of patients was assessed according to the percentage of patients with an observed improvement of diet, who could be discharged from hospital, and the duration in hospitals in relation to survival time (hospital stay). The QOL of patients with low-dose FP therapy was better than that of patients with usual combination chemotherapy. Low-dose FP therapy is a promising regimen for patients with far advanced gastric cancer.

Adenocarcinoma↗

Management of ipsilateral intrapulmonary metastases in the new TNM system for non-small cell lung cancer.

BACKGROUND: Recently, the Union Internationale Contre le Cancer and American Joint Committee on Cancer reclassified not only TNM staging but also ipsilateral intrapulmonary metastases (PM) as T4 in a same lobe or M1 in different lobes. To determine whether the new PM staging is appropriate, we studied the prognosis of PM. METHODS: From January 1981 to October 1997, we performed a lobectomy or pneumonectomy with mediastinal lymph node dissection, and had 42 patients with PM. We analyzed the postoperative prognosis of the patients with ipsilateral PM compared with the same stage group without PM (the non-PM). RESULTS: In the previous classification of PM (the old PM), 2 patients were categorized as stage IIA, 9 as IIB, 17 as IIIA, and 14 as IIIB. After reclassification (the new PM), 37 patients were categorized as stage IIIB, and 5 as IV. The old PM stage IIIA group had a significantly poor prognosis compared with the non-PM stage IIIA. However, the prognosis of the new PM group was compatible with that of the non-PM. None of the other staging group had a significant difference in the prognosis. CONCLUSIONS: The management of PM in the new TNM system for non-small cell lung cancer is appropriate.

Adenocarcinoma↗

Influence of diet and occlusal support on learning memory in rats behavioral and biochemical studies.

In order to verify the relationship between tooth loss and the learning memory in rat, male Wistar rats (25 weeks old) were divided into three separate groups: a control group (fed with a solid diet); a soft diet group (fed with a powder diet containing the same components as the solid one) and a molarless group (all molars were removed at 25 weeks and then fed with a powder diet). To evaluate both learning ability and memory, rats were tested with a one-way step through type of passive avoidance apparatus divided into light and dark chambers at 40-weeks. After the passive avoidance test, determination of acetylcholine (ACh) concentration of the cerebral cortex and hippocampus was performed. There was no significant difference between the molarless group and the control group in the response latency before the acquisition trails (non-stimulated period). At day 4 and 7 after the acquisition trials, the response latency of the molarless group was significantly shorter than that in the control group (p<0.05). The ACh levels of the molarless group in the cerebral cortex and hippocampus were significantly lower than that of the control group (p<0.05). It was apparent that tooth loss had an association with a loss of discriminative learning ability. This study suggested that the decrease of masticatory function caused by tooth loss leads to a decrease of ACh synthesis resulting in a learning memory disorder.

Acetylcholine↗

The structure of aquaporin-1 at 4.5-A resolution reveals short alpha-helices in the center of the monomer.

Aquaporin-1 is a water channel found in mammalian red blood cells that is responsible for high water permeability of its membrane. Our electron crystallographic analysis of the three-dimensional structure of aquaporin-1 at 4.5-A resolution confirms the previous finding that each subunit consists of a right-handed bundle of six highly tilted transmembrane helices that surround a central X-shaped structure. In our new potential map, the rod-like densities for the transmembrane helices show helically arranged protrusions, indicating the positions of side chains. Thus, in addition to the six transmembrane helices, observation of helically arranged side-chain densities allowed the identification of two short alpha-helices representing the two branches of the central X-shaped structure that extend to the extracellular and cytoplasmic membrane surfaces. The other two branches are believed to be loops connecting the short alpha-helix to a neighboring transmembrane helix. A pore found close to the center of the aquaporin-1 monomer is suggested to be the course of water flow with implications for the water selectivity.

Aquaporin 1↗

The duality of fish gonadotropin receptors: cloning and functional characterization of a second gonadotropin receptor cDNA expressed in the ovary and testis of amago salmon (Oncorhynchus rhodurus).

We previously isolated a cDNA encoding a gonadotropin receptor (sGTH-R) from amago salmon (Oncorhynchus rhodurus) ovarian follicles. In the present study, we cloned a second gonadotropin receptor (sGTH-RI) from the same RNA preparations. Overall sequence homology between sGTH-RI and sGTH-R is 44%. The highest homology occurs with mammalian FSH receptors (49%). Functional characterization examined in COS-7 cells transiently transfected with sGTH-RI showed the largest increase in cAMP production when exposed to salmon GTH I. These results provide the first evidence in any ectothermic vertebrate, the amago salmon, of the duality of gonadotropin receptors.

Amino Acid Sequence↗

Cloning, functional characterization, and expression of a gonadotropin receptor cDNA in the ovary and testis of amago salmon (Oncorhynchus rhodurus).

A gonadotropin receptor was cloned from amago salmon (Oncorhynchus rhodurus) ovarian follicles. This receptor (sGTH-R) belongs to the glycoprotein hormone receptor family with a large extracellular and seven-transmembrane domains. Its sequence homology is highest with mammalian LH receptors. Phylogenetic analysis reveals that sGTH-R is grouped with mammalian and chicken FSH and LH receptors, but not with mammalian TSH receptors. sGTH-R is expressed dominantly in the ovary and testis. Functional characterization examined with transiently transfected mammalian cells revealed increased intracellular cAMP level when exposed to mammalian and fish gonadotropins; the most potent hormone was salmon GTH II. These results indicate that the cloned cDNA encodes a functional amago salmon GTH receptor protein.

Amino Acid Sequence↗

Complexity of terminal airspace geometry assessed by lung computed tomography in normal subjects and patients with chronic obstructive pulmonary disease.

Increases in the low attenuation areas (LAA) of chest x-ray computed tomography images in patients with chronic obstructive pulmonary disease (COPD) have been reported to reflect the development of pathological emphysema. We examined the statistical properties of LAA clusters in COPD patients and in healthy subjects. In COPD patients, the percentage of the lung field occupied by LAAs (LAA%) ranged from 2.6 to 67.6. In contrast, LAA% was always <30% in healthy subjects. The cumulative size distribution of the LAA clusters followed a power law characterized by an exponent D. We show that D is a measure of the complexity of the terminal airspace geometry. The COPD patients with normal LAA% had significantly smaller D values than the healthy subjects, and the D values did not correlate with pulmonary function tests except for the diffusing capacity of the lung. We interpret these results by using a large elastic spring network model and find that the neighboring smaller LAA clusters tend to coalesce and form larger clusters as the weak elastic fibers separating them break under tension. This process leaves LAA% unchanged whereas it decreases the number of small clusters and increases the number of large clusters, which results in a reduction in D similar to that observed in early emphysema patients. These findings suggest that D is a sensitive and powerful parameter for the detection of the terminal airspace enlargement that occurs in early emphysema.

Forced Expiratory Volume↗

The projection structure of the membrane protein microsomal glutathione transferase at 3 A resolution as determined from two-dimensional hexagonal crystals.

The formation of two-dimensional crystals of the membrane-bound enzyme microsomal glutathione transferase is sensitive to fractional changes in the lipid-to-protein ratio. Variation of this parameter results in crystal polymorphism. The projection structure of a p6 crystal form of the enzyme has been determined by the use of electron crystallography. The unit cell at 3 A resolution is comprised of two trimers. The hexagonal p6 and the orthorhombic p21212 crystal types have common elements in the packing arrangement which imply dominant crystal contacts. An overall structural similarity between the protein molecules in the two crystal forms is suggested by the projection maps. Furthermore, a comparison of the p6 and p21212 projection maps identifies additional corresponding protein densities which could not be assigned to the microsomal glutathione transferase trimer previously. Surprisingly, an ambiguity of the rotational orientation was found for trimers interspersed at certain positions within the crystal lattice.

Animals↗

Lung carcinoma in patients age younger than 30 years.

BACKGROUND: To the authors' knowledge, no study regarding lung carcinoma patients age <30 years has been published. Therefore, this study was undertaken to define the characteristics of lung carcinoma patients age <30 years. METHODS: Information regarding 26 patients with primary lung carcinoma who were age <30 years was obtained from 10 medical institutions and reviewed retrospectively. For comparison, 304 patients age > or = 30 years who were admitted to the First Department of Internal Medicine at Toyama Medical and Pharmaceutical University between 1980-1996 were studied. RESULTS: Among the characteristics observed in the group of lung carcinoma patients age <30 years was a high incidence of female gender, no history of smoking, so-called "low grade malignancy," American Joint Committee on Cancer Stage I disease, and previous surgical resection. In addition, a low incidence of squamous cell carcinoma was noted, and a more favorable prognosis was observed. CONCLUSIONS: The current study noted clinical features that could be defined clearly in lung carcinoma patients age <30 years.

Adolescent↗

Ras proteins induce senescence by altering the intracellular levels of reactive oxygen species.

Human diploid fibroblasts eventually lose the capacity to replicate in culture and enter a viable but nonproliferative state of senescence. Recently, it has been demonstrated that retroviral-mediated gene transfer into primary fibroblasts of an activated ras gene (V12ras) rapidly accelerates development of the senescent phenotype. Using this in vitro system, we have sought to define the mediators of Ras-induced senescence. We demonstrate that expression of V12Ras results in an increase in intracellular and in particular, mitochondrial reactive oxygen species. The ability of V12Ras to induce growth arrest and senescence is shown to be partially inhibited by coexpression of an activated rac1 gene. A more dramatic rescue of V12Ras-expressing cells is demonstrated when the cells are placed in a low oxygen environment, a condition in which reactive oxygen species production is inhibited. In addition, in a 1% oxygen environment, Ras is unable to trigger an increase in the level of the cyclin-dependent kinase inhibitor p21 or to activate the senescent program. Under normoxic (20% O2) conditions, the V12Ras senescent phenotype is demonstrated to be unaffected by scavengers of superoxide but rescued by scavengers of hydrogen peroxide. These results suggest that in normal diploid cells, Ras proteins regulate oxidant production and that a rise in intracellular H2O2 represents a critical signal mediating replicative senescence.

Apoptosis↗

The structure of bacteriorhodopsin at 3.0 A resolution based on electron crystallography: implication of the charge distribution.

Electron crystallography has the potential to visualise the charge status of atoms. This is due to the significantly different scattering factors of neutral and ionised atoms for electrons in the low-resolution range (typically less than 5 A). In previous work, we observed two different types of densities around acidic residues in the experimental (|Fo|) map of bacteriorhodopsin (bR), a light-driven proton pump. We suggested that these might reflect different states of the acidic residues; namely, the protonated (neutral) and the deprotonated (negatively charged) state. To evaluate the observed charge more quantitatively, we refined the atomic model for bR and eight surrounding lipids using our electron crystallographic data set between 8.0 and 3.0 A resolution, where the charge effect is small. The refined model yielded an R-factor of 23.7% and a free R-factor of 33.0%. To evaluate the effect of charges on the density map, we calculated a difference (|Fo|-|Fc|) map including data of a resolution lower than 8.0 A resolution, where the charge effect is significant. We found strong peaks in the difference map mainly in the backbone region of the transmembrane helices. We interpreted these peaks to come from the polarisation of the polar groups in the main chain of the alpha-helices and we examined this by assuming a partial charge of 0.5 for the peptide carbonyl groups. The resulting R and free R-factors dropped from 0.250 and 0.341 to 0.246 and 0.336, respectively. Furthermore, we also observed some strong peaks around some side-chains, which could be assigned to positively charged atoms. Thus, we could show that Asp36 and Asp102 are likely to interact with cations nearby. In addition, peaks found around the acidic residues Glu74, Glu194 and Glu212 have different features and might represent positive charges on polarised water molecules or hydroxonium ions.

Amino Acid Sequence↗