Biomedical subjects

K Yoshimura

Publications and source records attributed to K Yoshimura.

At least 163 records · Page 9Linked to original sources

PubMed1999

Health consciousness of young people in relation to their personality.

Personality of targeted individuals can be assumed to influence behavior modification by health education. In this study the influence of personality on health consciousness was analyzed by a questionnaire for lifestyle, health consciousness, and the NEO-FFI personality test. Subjects were 942 new students in the Tokyo University of Agriculture who were surveyed in April, 1998. Separately performed health examination data were used to verify reliability of answers to the questionnaire. Among students, 83.2% of males and 90.4% of females felt themselves to be healthy, and more than 80% students desired to improve their health more. The rate of having no physical complaints, however, was only 31.7% in males and 20.4% in females. Distribution of NEO-FFI scores of neuroticism (N), extraversion (E), openness (O), agreeableness (A), and conscientiousness (C) corresponded well between males and females, except for significantly higher scores of O and A in females. Odds ratios (ORs) between high and low tertial points of NEO-FFI score for health consciousness were significantly elevated in the high scoring groups of E and C (OR = 6.26, 95% CI = 1.46-26.82, and OR = 6.04, 95% CI = 1.42-25.71, respectively) in males. On the contrary, high N and O groups had low health consciousness. Smoking habit was associated with high E scores (OR = 2.24, 95% CI = 1.13-4.43). Dietary habits, regular eating time, and avoidance of salty foods were associated with high C scores in both males and females. The OR of regular eating time was 2.66 (95% CI = 1.42-1.98), and 2.20 (95% CI = 1.31-3.71) for males and females, respectively. The OR of avoidance of salty foods were 2.09 (95% CI = 1.11-3.91), 1.87 (95% CI = 1.11-3.16) for males and females, respectively. Significant associations between lifestyle and personality require further study for risk association analysis and for relationship to interventive practices for prevention of lifestyle associated diseases.

Adolescent↗

PubMed1999

Environmental and possible genetic contributions to character dimensions of personality.

The relationship between dimensions of personality characteristics and the perceived rearing attitude of parents in the Japanese population were investigated. The scores on a measure of perceived parental attitude of 153 normal female students, measured on the Parker Parental Bonding Instrument, were correlated with personality features from the Japanese version of the Cloninger Temperament and Character Inventory. Self-directedness, especially the subclasses of Responsibility vs Blaming and Congruent Second Nature vs Incongruent Habits, was significantly related to high scores on Maternal Care and low scores on Maternal Overprotection. The subscale of Self-acceptance vs Self-striving correlated only with low scores on Maternal Overprotection. Paternal Care was only related to the total scale scores on Self-directedness. Results suggest that some personality traits may be related to the perceived attitudes of parents, especially of the mother, during childhood.

Adolescent↗

PubMed1999

Assisted reproduction technology for patients with congenital bilateral absence of vas deferens.

PURPOSE: We investigate the frequency of cystic fibrosis transmembrane conductance regulator gene mutations in Japanese patients with congenital bilateral absence of the vas deferens, and assess treatment outcomes of assisted reproduction interventions. MATERIALS AND METHODS: In 10 Japanese patients with bilateral congenital absence of the vas deferens genetic analysis was performed for known frequent mutations of the cystic fibrosis transmembrane conductance regulator gene using polymerase chain reaction amplification followed by dot-blot hybridization with the allele-specific oligonucleotide probes and direct sequencing. Intracytoplasmic sperm injection using spermatozoa retrieved from the testes was performed in 7 of the couples. RESULTS: No known mutations of the gene were detected in the patients. However, analysis of the polythymidine tract polymorphism in intron 8 revealed 30% allele frequency of 5T. Pregnancy was achieved in 7 cycles of intracytoplasmic sperm injection using spermatozoa retrieved from the testes. CONCLUSION: The 5T variant in intron 8 polythymidine tract was identified with high allelic frequency in Japanese patients with congenital bilateral absence of the vas deferens, suggesting that the disease in Japan is also partially caused by this particular mutation of the cystic fibrosis transmembrane conductance regulator gene. Modern assisted reproduction technology offers an important option for patients with congenital bilateral absence of the vas deferens.

Adult↗

PubMed1999

[A case of Ramsay Hunt syndrome associated with local meningitis, multiple cranial neuropathy, and the second cervical nerve involvement].

A 76-year-old man with herpetic vesicle in the right auricle developed ipsilateral 5th, 6th, 7th, and 8th cranial nerves involvement and pain in the dermatome of the second cervical nerve. The CSF study revealed elevated opening pressure up to 220 mmH2O, and pleocytosis up to 151 cells/mm3. Ninety-nine percent of the CSF cells were mononuclear cells. CSF protein was 47 mg/dl, and CSF glucose was 62 mg/dl. On the 24th hospital day the CSF cells decreased to 13/mm3 with 100% mononuclear cells. Titer of varicella-zoster virus (VZV) antibody was significantly elevated in CSF. Brain MRI and ABR demonstrated no abnormality. Although disorders of 5th and 6th cranial nerves and second cervical nerve improved, mild facial nerve palsy lasted and hearing disturbance showed no recovery. There are only seven cases of Ramsay Hunt syndrome associated with external ophthalmoplegia in the literature. However, un like the present case, none of these cases presented disorders of upper cervical nerves. In this case, we speculate that spreading of reactivated VZV caused local meningitis and multiple cranial nerve involvement as well as the second cervical nerve.

Abducens Nerve↗

PubMed1999

[A case of multiple endocrine neoplasia type 2A (MEN2A) with a mutation in the RET gene].

A 44-year-old woman complained of headache and palpitation. Magnetic resonance imaging showed bilateral adrenal tumors 10 x 9 cm in size on the left side and 8 x 4 cm in size on the right side. CT scan revealed a 0.7 x 0.7 cm mass in the thyroid. Hormonal examinations showed high values of urinary cathecholamines and serum calcitonin. DNA sequence analysis of peripheral white blood cells revealed that codon 634 in exon 11 of the RET gene was mutated from TGC (Cys) to TAC (Tyr). From these findings, a diagnosis was made of MEN2A with bilateral adrenal pheochromocytomas and medullary thyroid carcinoma. Bilateral adrenalectomy and thyroidectomy were performed. The same mutation of the RET gene was detected in all her 3 children, in two of whom, early stage medullary thyroid carcinoma was detected and thyroidectomy was performed. DNA analysis of the RET gene was useful for the diagnosis of carriers of MEN2A and the early detection of medullary thyroid carcinoma.

Adolescent↗

PubMed1999

[Non-Hodgkin's lymphoma with Toxoplasma encephalitis].

A 62-year-old man was admitted to our hospital due to fever and systemic lymph-node swelling on June 9, 1998. He was given a diagnosis of non-Hodgkin's lymphoma (diffuse mixed T cell lymphoma) with involvement of mediastinum and para-aortic lymph nodes, pleura, peritoneum, and bone marrow. After diagnosis, combined chemotherapy (CHOP regimen) was started. On day 11, the patient's consciusness level suddenly deteriorated. A brain computed tomographic scan showed no abnormal findings. A cytospin smear of cerebrospinal fluid disclosed tachyzoides (Toxoplasmic bodies), thus yielding a diagnosis of Toxoplasma encephalitis. Oral sulfadoxine pyrimethamine rapidly alleviated the patient's consciousness disturbance. One month later, a cytospin smear and RT-PCR analysis of cerebrospinal fluid detected no tachyzoides. Complete remission of lymphoma was achieved after 2 courses of CHOP therapy. Toxoplasma encephalitis should be considered a potential cause of consciousness disturbance in immunocompromised hosts, such as patients with malignant lymphoma. Cytospin smears of cerebrospinal fluid are a useful tool for the early diagnosis of Toxoplasma encephalitis.

Animals↗

PubMed1999

Treatment of cholecystoduodenal fistula by laparoscopy.

We describe a patient with cholecystoduodenal fistula treated by a laparoscopic approach. Use of a flexible videoscope, flexible retractor, and endoscopic transecting stapler allows for laparoscopic treatment of cholecystoenteric fistulae.

Biliary Fistula↗

PubMed1999

[An analysis of the cardiovascular responses under hyper- and hypo-gravity environments using a mathematical model].

Gravity affects cardiovascular control system remarkably. Internal control mechanism responsible for such cardiovascular changes under hypo- and hyper-gravity have not yet been fully understood, although many biological and physiological measurements as to cardiovascular system have been conducted since man's first exploration to space. One reason for this arises from the difficulty in continuous and simultaneous measurements of hemodynamics of many parts of the body. To overcome this difficulty, a mathematical model was constructed based on animal and human physiological evidence in our previous study. In the present study, the model is used for explaining hemodynamics during hyper- and hypo-gravity environments obtained during parabolic flight. The parabolic flight experiment was conducted by a small rear-jet MU300. Three university male students volunteered as subjects. Five to eleven parabolic flights per day were performed for 6 days. The subjects sat on a chair either in an upright position or a 45 degree reclining position. Electrocardiogram and finger blood pressure were measured continuously during the flights. Variable parameters of the model were adjusted so that heart rate and blood pressure of the model fit to those of the experiment. It was shown that the model can quantitatively reproduce and predict experimental heart rate and blood pressure during a parabolic flight. Analysis of internal property of the model revealed hemodynamics of the human cardiovascular system during a parabolic flight which explains the mechanisms of cardiovascular responses under hyper- and hypo-gravitational environments.

Blood Pressure↗

PubMed1998

Mechanosensitive channels in the cell body of Chlamydomonas.

Mechanosensitive channels appear ubiquitous but they have not been well characterized in cells directly responding to mechanical stimuli. Here, we identified tension-sensitive channel currents on the cell body of Chlamydomonas, a protist that shows a marked behavioral response to mechanical stimulation. When a negative pressure was applied to the cell body with a patch clamp electrode, single-ion-channel currents of 2.4 pA in amplitude were observed. The currents were inhibited by 10 micrometer gadolinium, a general blocker of mechanosensitive channels. The currents were most likely due to Ca2+ influxes because the current was absent in Ca2+-free solutions and the reversal potential was 98 mV positive to the resting potential. The distribution of channel-open times conformed to a single exponential component and that of closed times to two exponential components. This mechanosensitive channel was similar to the one found in the flagella in the following respects: both channels were inhibited by Gd3+ at 10 micrometer but not at 1 micrometer both passed Ca2+ and Ba2+; their kinetic parameters for channel opening were similar. These observations raise the possibility that identical mechanosensitive channels may function both in the behavioral control through the mechanoreception by the flagella and in the regulation of cellular physiology in response to mechanical perturbation on the cell body.

Animals↗

PubMed1998

Monoclonal antibody 14F7, which recognizes a stage-specific immature oligodendrocyte surface molecule, inhibits oligodendrocyte differentiation mediated in co-culture with astrocytes.

Cells at an intermediate stage of oligodendrocyte lineage are not only well characterized by biochemical studies but also are likely to relate to the outcome of physiological events. To elucidate the molecular events leading to the development of oligodendrocyte lineage cells, we have raised monoclonal antibodies against stage-specific immature oligodendrocytes, which have previously been isolated by a novel oligodendrocyte-lineage cell culture technique (Sakurai et al.: J Neurosci Res 52:17-26, 1998). We have isolated a mouse monoclonal antibody termed 14F7 which predominantly labels stage-specific immature oligodendrocytes and have found that the expression of 14F7 immunoreactivity in the developing neonatal rat forebrain is closely associated with cells expressing the oligodendrocyte progenitor marker A2B5 and to immature oligodendrocyte expressing O4 antigen. 14F7+ cells were distributed in the ventricular and subventricular zone and the nearby forming corpus callosum as non-myelinating cells. In contrast to cell culture observations, 14F7+ cells were seen only in oligodendrocyte lineage cells. For instance, dissociated cell culture studies indicated that 14F7 labels a cell surface molecule, and its cellular distribution is coincident with all of O4+ cells and A2B5+ cells, and even A2B5- cells. By contrast, 14F7-positive cells did not label astrocytes and, furthermore, did not label myelin basic protein (MBP)-positive oligodendrocytes. 14F7 recognized a 48-kDa protein on sodium dodecyl sulfate polyacrylamide gel electrophoresis. 14F7 immunoreactivity was detectable in rat brain as early as embryonic day 18. Furthermore, in these cells, the total time for differentiation was extended, and on maturation, these cells subsequently expressed an array of myelin-specific proteins, which normally occurs by direct contact with type-1 astrocytes. However, in the presence of 14F7, stage-specific oligodendrocytes co-cultured with astrocytes completely failed to express MBP. These data suggest that the 14F7 antigen is a novel cell surface molecule that is expressed in the intermediate stage of oligodendrocyte-lineage cells, and it is expected that it regulates the differentiation of oligodendrocyte throughout development.

Animals↗

PubMed1998

Comparative study on recombinant chloroplastic and cytosolic ascorbate peroxidase isozymes of spinach.

The spinach stromal, thylakoid-bound, and cytosolic ascorbate peroxidase isozymes (EC 1.11.1.11) were overexpressed in Escherichia coli, and their enzymatic properties were compared with the respective native isozymes. The purification of the recombinant stromal and cytosolic ascorbate peroxidases using the conventional column chromatography yielded 0.73 and 2.2 mg of protein/liter of bacteria culture with enzyme activities of 800 and 486 micromol min-1 mg protein-1, respectively. In every respect, the recombinant stromal, thylakoid-bound, and cytosolic ascorbate peroxidase isozymes exhibited identical enzymatic properties with each native isozyme. Specifically, the recombinant stromal and thylakoid-bound ascorbate peroxidase isozymes showed high utilization of ascorbate as an electron donor and had a very short lifetime in ascorbate-depleted medium. Polyclonal antibodies raised against both purified recombinant stromal and cytosolic ascorbate peroxidase isozymes were prepared. Both antibodies showed a cross-reaction with the recombinant and native ascorbate peroxidase isozymes.

Amino Acid Sequence↗

PubMed1998

Effects of S-8510, a novel benzodiazepine receptor partial inverse agonist, on basal forebrain lesioning-induced dysfunction in rats.

We investigated the effects of a novel benzodiazepine partial inverse agonist, S-8510 (2-(3-isoxazolyl)-3,6,7,9-tetrahydroimidazo [4,5-d] pyrano [4,3-b] pyridine monophosphate monohydrate), on the impairment of spatial memory, decreased high-affinity choline uptake and acetylcholine release in basal forebrain-lesioned rats. S-8510 (3 and 5 mg/kg, p.o. 30 min before each training session) significantly ameliorated the basal forebrain-lesion-induced impairment of spatial memory in water maze task. In vivo brain microdialysis studies showed that systemic administration of S-8510 at 3 and 10 mg/kg significantly increased the release of acetylcholine in the front-parietal cortex in basal forebrain-lesioned rats. Further, repeated administration of S-8510 (3 and 10 mg kg(-1) day(-1) for 5 days) reversed the decrease in cortical high-affinity choline uptake induced by basal forebrain lesion. Thus, S-8510 improved the spatial memory impairment induced by lesion of the basal forebrain in rats. In addition, it increased acetylcholine release and high-affinity choline uptake from the cortex, a region closely associated with memory, in basal forebrain-lesioned rats. These results indicate that S-8510 has cognition enhancing and cholinergic-activating effects in the basal forebrain-lesioned rats, suggesting that this agent may be useful for the treatment of mild to moderate senile dementia including Alzheimer's disease.

Acetylcholine↗

PubMed1998

The clinicopathologic significance of small areas unstained by Lugol's iodine in the mucosa surrounding resected esophageal carcinoma: an analysis of 147 cases.

BACKGROUND: Small areas unstained with Lugol's iodine are often observed in the mucosa surrounding esophageal carcinomas. METHODS: For light microscopic evaluation, the histologic features of 131 small areas unstained by Lugol's iodine in 12 selected cases were investigated. For clinicopathologic evaluation, the numbers of small areas unstained by Lugol's iodine in the mucosa surrounding 147 consecutively resected esophageal carcinomas, including these 12 cases, were counted. The relation between the incidence of such areas and the development of multiple primary cancers in the upper aerodigestive tract was examined together with data on the patients' tobacco and alcohol consumption. RESULTS: Ninety-two percent (131) of the small areas unstained by Lugol's iodine contained dysplastic lesions. Seventeen (12%) of the 147 resected specimens contained fewer than 5 small unstained areas, whereas 52 (35%) had 6-10 and 78 (53%) had more than 11 such areas. The incidence of multicentric cancer in the upper aerodigestive tract and the average alcohol index scores were significantly higher for patients who had more than 11 unstained areas than for patients who had fewer than 5 such areas (P < 0.01). CONCLUSIONS: Lugol's iodine staining method is useful for detecting groups at high risk of multicentric cancer in the upper aerodigestive tract.

Adult↗

PubMed1998

Colcemid-induced apoptosis of cultured human glioma: electron microscopic and confocal laser microscopic observation of cells sorted in different phases of cell cycle.

The effect of the antitubulin agent colcemid on human glioma cells was investigated by sorting cells with different DNA content and subjecting them to confocal laser microscopy and transmission electron microscopy. The human glioma cell line U251MG was exposed to colcemid at a concentration of 0.05 microg for 16 h. Flow cytometric analysis revealed the accumulation of cells in S/G2M phase. Cells harvested from each of G0/G1 and S/G2M peaks were then analyzed by confocal laser microscopy and transmission electron microscopy. Confocal laser microscopy revealed that colcemid-treated cells harvested from the G0/G1 peak contained mitotic and apoptotic cells in addition to interphase cells. Electron microscopy confirmed that colcemid-treated cells in the G0/G1 peak had fragmented nuclei typical of apoptotic cells and mitotic cells with altered chromatin structure. Some mitotic cells obtained by mitotic shake-off after treatment with colcemid showed DNA strand breaks defined by in situ nick end labeling. The present study indicates that mitotic as well as interphase apoptosis occurs in U251MG cells following colcemid treatment.

Apoptosis↗

PubMed1998

Differentiation of oligodendrocyte occurs in contact with astrocyte.

We have generated stage-specific oligodendrocytes, which are identified as immature oligodendrocytes by the expression of specific markers. These cells were generated by using 3 types of intrinsic and extrinsic factors for influencing the characteristics of oligodendrocyte-lineage cells. The factors included 10% serum in the medium to induce cell proliferation, bFGF in serum-free medium to increase survival and induce differentiation, and 0.25% trypsin to remove nonoligodendrocyte lineage cells. We have also demonstrated that it is possible to supply a huge amount of homogeneous populations of stage-specific immature oligodendrocytes after 35 days' culture. The maturation of these cells is controlled by interacting with astrocytes in vitro, resulting in the expression of MBP isoforms (14.0 and 18.5 kDa) that may participate in mature oligodendrocyte membrane compaction.

Animals↗

PubMed1998

Cyclic AMP potentiates substance P-induced amylase secretion by augmenting the effect of calcium in the rat parotid acinar cells.

Potentiation of amylase secretion by the combination of isoproterenol and substance P was examined in perfused rat parotid acinar cells. Combined additions of substance P and isoproterenol evoked biphasic changes in amylase secretion, an initial large peak and the following sustained plateau: the magnitudes of the both responses were higher than the sum of the responses induced by each agonist alone. Isoproterenol also increased the maximum response and the apparent affinity (EC50) for substance P to evoke the initial peak response; the EC50 values were about 20 and 0.8 nM, respectively, in the absence and the presence of isoproterenol. On the other hand, 1 nM substance P was sufficient for evoking the maximum potentiation of the sustained plateau response. Substance P did not change the EC50 for isoproterenol. The effect of isoproterenol was mimicked with dibutyryl cyclic AMP and agonists that increase parotid cyclic AMP. Omission of Ca2+ or addition of 5 mM nickel chloride almost completely abolished the potentiation of the sustained plateau, but little decreased that of the initial peak. Depletion of Ca2+ in InsP3-sensitive intracellular stores with thapsigargin, on the other hand, decreased the initial peak response, but not the sustained plateau, to substance P. The potentiation was also observed between isoproterenol and Ca2+ ionophores. Switching to the solutions containing higher concentrations of Ca2+ during the continuous stimulation with isoproterenol or IBMX evoked a large, but transient, response of amylase secretion. Time course of changes in amylase secretion induced by isoproterenol and substance P in combination was very similar to that of substance P, but not of isoproterenol. Isoproterenol did not enhance the effect of substance P on [Ca2+]i. These results show that the potentiation is mainly, if not totally, caused by cyclic AMP-induced enhancement of the potency and the efficacy in the pathway regulated by Ca2+.

1-Methyl-3-isobutylxanthine↗

PubMed1998

Expression of basic fibroblast growth factor is associated with resistance to cisplatin in a human bladder cancer cell line.

To clarify the role of basic fibroblast growth factor (FGF-2) in the drug resistance of bladder cancer, we transfected the FGF-2 gene into HT1376, an FGF-2 negative human bladder cancer cell line. The FGF-2-transfected cell lines exhibited three- to four-fold higher resistant potential to cisplatin than the vector-only transfected control cell lines in vitro. When cisplatin was injected intraperitoneally after s.c. implantation of HT1376 sublines into nude mice, FGF-2 transfectants formed tumors about twice as large as did controls. In contrast, there was no significant difference in either cell proliferation in vitro or tumor growth in vivo among these cell lines without cisplatin treatment. Furthermore, DNA degradation following cisplatin treatment was markedly suppressed in FGF-2 transfectants compared to control cells. These results suggest that the expression of the FGF-2 gene plays an important role in the acquisition of the cisplatin-resistant phenotype of bladder cancer, probably through the protection against cisplatin-induced apoptosis.

Animals↗

PubMed1998

Real-time observation of Ca2+-induced basal body reorientation in Chlamydomonas.

The two basal bodies of Chlamydomonas are connected by a bridge, the distal fiber, that contains a Ca2+-binding protein, centrin. Although various fibrous structures in many organisms containing centrin or similar proteins have been shown to contract at Ca2+ concentrations >10(-7)-10(-6) M, the contractility of the distal fiber in Chlamydomonas has not been demonstrated. To determine whether it undergoes Ca2+-dependent contraction, we isolated the flagella-basal body complex from the paralyzed-flagella mutant pf18 and measured the angle between the two axonemes at different Ca2+ concentrations. Use of a double mutant with the mutant fa1, deficient in the mechanism for Ca2+-dependent flagellar amputation, enabled the measurement at Ca2+ concentrations > or = 10(-4) M. The angle, 80-120 degrees at 10(-9) M Ca(2-), was found to decrease by about 20 degrees when the Ca2+ concentration was raised above 10(-6) M. The angle increased again when the Ca2+ concentration was lowered below 10(-7) M. The flagellar apparatuses isolated from the double mutant between pf18 and the mutant vfl2 deficient in the structural gene of centrin had an angle of 90-130 degrees at 10(-9) M Ca2+, but the angle did not change when the Ca2+ concentration was increased. Thus centrin must be involved in the basal body reorientation. In detergent-extracted cell models of the pf18fa1 mutant, the angle between the two axonemes was found to decrease transiently by about 15 degrees upon iontophoretic application of Ca2+. Hence, the Ca2+-induced basal body reorientation can take place even when the basal body is contained in the cell body covered by the cell wall. It may function as part of the mechanism for phobic responses wherein Chlamydomonas cells swim backward transiently upon reception of strong light or mechanical stimuli.

Animals↗