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Biomedical subjects

T Hiura

Publications and source records attributed to T Hiura.

At least 19 recordsLinked to original sources
PubMed2006

Leaf anatomy and light acclimation in woody seedlings after gap formation in a cool-temperate deciduous forest.

The photosynthetic light acclimation of fully expanded leaves of tree seedlings in response to gap formation was studied with respect to anatomical and photosynthetic characteristics in a natural cool-temperate deciduous forest. Eight woody species of different functional groups were used; two species each from mid-successional canopy species (Kalopanax pictus and Magnolia obovata), from late-successional canopy species (Quercus crispula and Acer mono), from sub-canopy species (Acer japonicum and Fraxinus lanuginosa) and from vine species (Schizophragma hydrangeoides and Hydrangea petiolaris). The light-saturated rate of photosynthesis (Pmax) increased significantly after gap formation in six species other than vine species. Shade leaves of K. pictus, M. obovata and Q. crispula had vacant spaces along cell walls in mesophyll cells, where chloroplasts were absent. The vacant space was filled after the gap formation by increased chloroplast volume, which in turn increased Pmax. In two Acer species, an increase in the area of mesophyll cells facing the intercellular space enabled the leaves to increase Pmax after maturation. The two vine species did not significantly change their anatomical traits. Although the response and the mechanism of acclimation to light improvement varied from species to species, the increase in the area of chloroplast surface facing the intercellular space per unit leaf area accounted for most of the increase in Pmax, demonstrating the importance of leaf anatomy in increasing Pmax.

Acclimatization↗
PubMed2001

Infrared spectra of 1 -monopalmitin- or 1-monostearin-water systems in the gel phase.

The infrared spectra of 1-monopalmitin- or 1-monostearin-water systems in the gel phase were observed at room temperature. In both systems the infrared intensities of the bands parallel and perpendicular to the paraffin chain are relatively reduced and enhanced, respectively, on going from the crystalline phase to the gel phase. These spectral changes are explained in terms of the interaction among oscillating dipoles, which is sensitive to the morphology change from the three-dimensional crystalline phase to the two-dimensional lipid bilayers. The non-planar lipid bilayers are proposed for the gel phase in monopalmitin-water systems with x > or = 35 (x: wt.% water).

Gels↗
PubMed2001

Asymptomatic brain tumor detected at brain check-up.

Brain check-up was performed in 4000 healthy subjects who underwent medical and radiological examinations for possible brain diseases in our hospital from April 1996 to March 2000. Magnetic resonance imaging revealed 11 brain tumors which consisted of six meningiomas, three pituitary adenomas, one astrocytoma, and one epidermoid cyst. The detection rate of incidental brain tumor in our hospital was 0.3%. Nine patients underwent surgery, with one case of morbidity due to postoperative transient oculomotor nerve paresis. The widespread use of brain check-up may increasingly detect asymptomatic brain tumors. Surgical indications for such lesions remain unclear, and the strategy for treatment should be determined with consideration of the patient's wishes.

Adenoma↗
PubMed2001

[Cerebral arteritis and cerebritis caused by subdural empyema: two cases report].

We report two cases of cerebral angitis and cerebritis caused by subdural empyema. A 22-year-old man, who complained of a headache and high fever, suddenly developed unconsciousness and right hemiparesis. CT and MRI demonstrated left subdural empyema with diffuse brain swelling. CT angiography showed diffuse narrowing of the left internal carotid artery, middle cerebral artery, and anterior cerebral artery. Although we performed craniotomy, continuous irrigation with drainage, systemic injection of antibiotics for subdural empyema, antiplatelet therapy, and hyperbaric oxygen therapy for angitis, his condition remained unchanged. A 67-year-old man who had previously undergone burr hole surgery presented to our hospital for the treatment of scalp infection. He suddenly developed unconsciousness and right hemiparesis. CT and MRI demonstrated left subdural empyema with diffuse brain swelling, but MR angiography did not show any abnormal findings. Hemiparesis improved after the surgery and systemic injection of the antibiotics. Subdural empyema with sinusitis or meningitis around the skull base sometimes causes cerebral angitis. We considered that the angiographical evaluation for the subdural empyema was necessary to detect angitis.

Adult↗
PubMed1999

Enhancement of allergic inflammation by diesel exhaust particles: permissive role of reactive oxygen species.

BACKGROUND: Diesel emission particulates (DEP) exert effects on the immune system and act as an adjuvant which enhances allergic inflammation. Animal and human models have delineated the effects of DEP chemicals in enhancing IgE production and promoting T-helper cell-2 (Th2) differentiation. An important primary effect that can explain the DEP-associated humoral and cellular immune responses is the induction of macrophage responses by DEP chemicals. This includes effects on macrophage production of cytokines and chemokines, which may play a role in enhancing allergic inflammation. A potent mechanism in macrophages exposed to DEP chemicals involves the generation of reactive oxygen species (ROS), leading to cellular activation or apoptosis which can be abrogated by antioxidants. CONCLUSION: These findings may establish a role for antioxidant therapy in diminishing the effects of particulate pollutants in asthma.

Asthma↗
PubMed1999

Effects of clotrimazole on the growth, morphological characteristics, and cisplatin sensitivity of human glioblastoma cells in vitro.

OBJECT: Clotrimazole, an antimycotic drug, inhibits proliferation of normal and cancer cells by downregulating the movement of intracellular Ca++ and K+. The authors examined the effect of clotrimazole on the growth and sensitivity to cisplatin of two human glioblastoma cell lines--A172, which has the wild-type p53 gene, and T98G, which has the mutant p53 gene in vitro. METHODS: The A172 and T98G glioblastoma cells were exposed to clotrimazole and cell growth was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium chloride colorimetric assay. Clotrimazole produced a dose-dependent inhibition of cell proliferation and caused changes in cellular structure toward a well-differentiated form. The growth inhibitory effect of clotrimazole was reversible. Western immunoblot analysis revealed a marked increase in cellular glial fibrillary acidic protein and wild-type p53 and a decrease in c-myc and c-fos oncoproteins in both cell lines treated with clotrimazole. Flow cytometric analysis revealed that clotrimazole-treated cells accumulated in the G0/G1 phase with a marked decrease in cells in the S phase; when clotrimazole was washed out from the culture medium, cells again started to proliferate, with a marked decrease in cells in the G0/G1 phase and an increase in cells in the S phase. The growth inhibitory effect of clotrimazole could not be overcome by exogenous stimulation with either epidermal growth factor or c-myc peptide. A combined treatment with clotrimazole and cisplatin significantly enhanced cell cytotoxicity compared with treatment using either drug alone. A DNA fragmentation assay showed that both clotrimazole and cisplatin induced apoptosis, which was increased in cells treated by both drugs. CONCLUSIONS: The present study indicates that clotrimazole inhibits cell proliferation accompanied by morphological changes toward differentiation of glioblastoma cells and that this drug synergistically enhances the antitumor effect of cisplatin by inducing wild-type p53-mediated apoptosis.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

Fruit set in Styrax obassia (Styracaceae): the effect of light availability, display size, and local floral density.

Maternal reproductive success was examined in Styrax obassia (Styracaceae), a bumble-bee pollinated mass-flowering tree in a cool-temperate deciduous forest in northern Japan. The effects of flower number on the success of individual flowers at three levels (inflorescence, individual, and population) were considered. During 1995 and 1996, variations in size, light availability to branches, floral display size, and fruit set were monitored in 37 out of 211 individual S. obassia trees in a 4-ha forest plot. In addition, the locations of the 211 trees in this plot were mapped and the number of inflorescences in each tree was counted. A multiple regression analysis showed that flower number per inflorescence and inflorescence number per individual had negative effects on fruit set, and inflorescence number of aggregated clumps of flowering trees, tree size, and light resource had positive effects on fruit set although significant level were marginal. It is concluded that pollinator attraction may occur not at the individual tree level, but at the level of a clump of flowering trees. It is also suggested that geitonogamy increased with inflorescence number of tree and inflorescence size and that resource limitation was related to the light condition and variation of tree size.

Journal Article↗
PubMed1998

Immunohistochemical analysis of metallothionein in astrocytic tumors in relation to tumor grade, proliferative potential, and survival.

BACKGROUND: Metallothionein (MT) is the name for a family of predominantly intracellular protein thiol compounds involved in anticancer drug resistance. For certain tumors, MT is related to grade of tumor malignancy and prognosis. The authors evaluated the expression of MT in 114 astrocytic tumors in relation to the proliferative potential of tumors and the survival of patients. METHODS: Paraffin embedded tissue sections were stained with monoclonal anti-metallothionein and MIB-1 Ki-67 antibodies by avidin-biotin complex immunohistochemistry. RESULTS: MT expression was observed in 2 of 6 pilocytic astrocytomas, in 10 of 24 Grade 2 astrocytomas, in 16 of 25 anaplastic astrocytomas, and in 47 of 59 glioblastomas. In addition to the tumor cells, microvascular endothelial proliferation and smooth muscle of tumor vessel walls were frequently MT positive. The glioblastomas had a significantly higher percentage of MT positive cells compared with low grade (P < 0.0001) and anaplastic (P < 0.04) astrocytomas. MT expression in astrocytomas had no correlation with tumor recurrence. The mean Ki-67 labeling index (LI) was significantly higher in the high grade (3-4) compared with the low grade (1-2) astrocytomas. MT positive astrocytic tumors had statistically significantly higher mean Ki-67 LI compared with MT negative tumors, irrespective of histologic grade. Although the levels of MT and Ki-67 LI varied in individual tumors, the mean Ki-67 LI increased in parallel to the increasing MT staining grade, and this difference attained statistical significance only for glioblastoma. MT positive anaplastic astrocytoma and glioblastoma patients did not survive as long as the MT negative patients, although this difference attained statistical significance only for anaplastic astrocytoma. CONCLUSIONS: The current study suggests that MT might play a significant role in the growth of astrocytic tumors, with an acquired enhanced ability to produce MT as the malignant potential of a tumor increases.

Adolescent↗
PubMed1998

Macrophage activation by polycyclic aromatic hydrocarbons: evidence for the involvement of stress-activated protein kinases, activator protein-1, and antioxidant response elements.

Polycyclic aromatic hydrocarbons (PAH) contained in fossil fuel combustion particles enhance the allergic response to common environmental Ags. A key question is: what are molecular pathways in the immune system by which PAH and conversion products drive allergic inflammation? Circumstantial evidence suggests that macrophages are involved in PAH-induced responses. We demonstrate that a representative PAH, beta-napthoflavone (BNF), and a representative quinone metabolite, tert-butylhydroxyquinone (tBHQ), induce Jun kinase and p38 mitogen-activated protein kinase activities in parallel with the generation of activator protein-1 (AP-1) mobility shift complexes in THP-1 and RAW264.7 macrophage cell lines. Activation of mitogen-activated protein kinases was dependent on generation of oxidative stress, and could be inhibited by N-acetylcysteine. Another genetic response pathway linked to PAH is the antioxidant response element (ARE), which regulates expression of detoxifying enzymes. BNF and tBHQ activated a human ARE (hARE) reporter gene in RAW264.7 cells. Interestingly, bacterial lipopolysaccharide also induced hARE/chloramphenicol acetyltransferase activity. While the hARE core, GTGACTCAGC, contains a consensus AP-1 sequence (underlined), AP-1 was not required for hARE activation. This suggests that PAH and their conversion products operate via ARE-specific transcription factors in the immune system. BNF and tBHQ did, however, induce AP-1 binding to the hARE, while constitutively active Jun kinase interfered in hARE/chloramphenicol acetyltransferase activation. This suggests that AP-1 proteins negatively regulate the hARE. These data establish important activation pathways for PAH in the immune system and provide us with targets to modulate the effect of environmental pollutants on allergic inflammation.

Animals↗
PubMed1998

Immunohistochemical analysis of p53 and p21 in human primary glioblastomas in relation to proliferative potential and apoptosis.

The Cdk inhibitor p21/WAF1 can be transcriptionally activated by wild-type p53, not by mutant p53, and functions to block cell-cycle progression in many human neoplasms. We examined the immunohistochemical expression of p53 and p21 in 35 human primary glioblastomas in relation to tumor proliferation potential as assessed by the Ki-67 labeling index (LI) and the glioblastoma apoptosis index (AI). The expression of mutant p53 was observed in 74% of glioblastomas, wild-type p53 in 18% of glioblastomas, and p21 in 57% of glioblastomas. p21 expression was seen in 15 of 26 mutant p53-positive and 2 of 4 wild p53-positive tumors. Tumor Ki-67 LI correlated neither with p53 nor with p21 expression in glioblastomas. Apoptosis was identified in all 15 glioblastomas examined, with a mean (+/-SD) Al of 1.69+/-1.54, and correlated neither with p53 (wild or mutant) nor with p21 expression. The results of the present study suggest that p53 mutation and p21 protein expression are frequent in primary glioblastoma but lack correlation with tumor proliferation potential and apoptosis. The lack of correlation between p21 and p53 also suggests that p21 in glioblastomas may be induced by a p53-independent pathway.

Adult↗
PubMed1998

Enhancement of allergic inflammation by the interaction between diesel exhaust particles and the immune system.

There is growing evidence that fossil fuel combustion products act as adjuvants in the immune system and may lead to enhancement of allergic inflammation. Through this mechanism, particulate air pollutants may be an important contributor to the increased prevalence and morbidity of asthma and allergic rhinitis. In this communication we focus on the role of diesel exhaust particles (DEPs) in skewing the immune response towards IgE production and induction of allergic inflammation. We review experimental studies in animals and humans showing that DEPs enhance IgE production by a variety of mechanisms, including effects on cytokine and chemokine production, as well as activation of macrophages and other mucosal cell types. We discuss metabolic and cellular activation pathways linked to chemicals such as polycyclic aromatic hydrocarbons contained in DEPs and demonstrate how these molecular events may impact cytokine, chemokine, and accessory molecule expression in the immune system.

Animals↗
PubMed1997

Immunohistochemical analysis of progesterone receptor and Ki-67 labeling index in astrocytic tumors.

BACKGROUND: Intracranial tumors such as meningiomas express steroid hormone receptors but little is known regarding progesterone receptor (PR) in astrocytic tumors. The authors evaluated expression of PR in 86 astrocytic tumors in relation to tumor proliferative potential. METHODS: Paraffin embedded tumor sections were stained with polyclonal antiprogesterone antibody by the peroxidase-antiperoxidase method and with monoclonal MIB-1-Ki-67 antibody by avidin-biotin complex immunohistochemistry. RESULTS: Sixty-three of the 86 astrocytic tumors (73%) showed positive PR immunoreactivity. PR expression was observed in 4 of 9 pilocytic astrocytomas, 13 of 24 Grade 2 astrocytomas, 15 of 20 anaplastic astrocytomas, and 31 of 33 glioblastomas. In addition to the tumor cells, cells of microvascular endothelial proliferation and the smooth muscle of tumor vessel walls were frequently PR positive. Glioblastomas had a significantly higher percentage of PR positive cells compared with anaplastic (P < 0.0008) and low grade (P < 0.0001) astrocytomas. Patients with PR positive astrocytomas were of an older age than patients with PR negative astrocytomas (48.71 +/- 21.95 years vs. 37.09 +/- 24.69 years; P < 0.04). The mean Ki-67 labeling index (LI) was significantly higher in the high grade (3-4) astrocytomas compared with low grade (1-2) astrocytomas (P < 0.0001). PR positive astrocytic tumors had higher Ki-67 LI than PR negative tumors. PR expression was not correlated with tumor recurrence and patient survival. CONCLUSIONS: The current study suggests that PR in the astrocytic tumors correlates with histologic grade and PR may participate in the growth of these tumors and tumor angiogenesis. The measurement of PR in these tumors may indirectly represent tumor growth potential.

Adolescent↗
PubMed1995

Minigemistocytic astrocytoma with frequent apoptoses: analysis of tumor growth.

A rare glial tumor known as 'minigemistocytic astrocytoma (gliofibrillary oligodendroglioma)' is reported in a 73 year old Japanese male. A low-density area found by computed tomography and thought to be an operative scare remaining after hematoma in the right frontal lobe of the cerebrum had been followed for 10 years. This area, however, had been accompanied by a cyst for 2 years and had developed gradually for 1 year prior to dissection. The tumor was poorly demarcated from the surrounding normal tissue macroscopically at operation. Microscopically, the tumor consisted of small gemistocytic cells in uniform sheets intersected by a small vascular stroma with frequent eosinophilic granular bodies, mitoses and apoptotic bodies. Immunohistochemical examination for glial fibrillary acidic protein (GFAP) revealed remarkable positive reactivity in the perinuclear cytoplasm, but no immunoreactivity for vimentin or Leu 7 was found. Electron microscopically, rich filaments arranged in parallel bundles were found in the neoplastic cells. These histological findings are closely consistent with those of previously reported minigemistocytic astrocytoma cases. The GFAP-rich minigemistocytic astrocytoma with granular bodies and frequent mitoses in the present case is considered to indicate a higher degree of astrocytic differentiation and malignant potential than previous cases. The frequent apoptoses, however, might inhibit tumor growth in this case.

Aged↗
PubMed1986

[Retroperitoneal liposarcoma with various histological figures].

A case of retroperitoneal liposarcoma consisting of three large nodules with three different types of histologic findings is presented. A 69-year-old man was diagnosed as having a malignant tumor in the retroperitoneum and underwent successful tumor extirpation. The resected tumor had three different type of nodules, 18 X 15 X 7.0 cm, 8 X 15 X 4.0 cm, 15 X 10 X 2.5 cm in size, respectively. The histologic examination revealed myxoid, well-differentiated fibrosing and lipoma-like liposarcoma type, respectively. Chemotherapy was undertaken postoperatively, and there is no evidence of recurrence two years after surgery.

Aged↗
PubMed1984

[Preoperative immunochemotherapy for gastric cancer combined with perifocal administration of OK-432].

OMF treatment consisting of perifocal administration of OK-432 associated with MMC and 5-FU was applied for 37 lesions of 35 cases including 2 with multiple cancer. The results obtained were as follows lesions. Macroscopical efficacy was rated as "good" in 12 lesions (32.4%), "fair" in 24 lesions (64.9%) and "poor" in 1 case. Histological efficacy was assessed as "++" for 10 lesions (27%), and "+" for 16 lesions (43.2%). Taking "+" or higher histologically as "effective", the efficacy rate was approximately 71%. Efficacy rate for metastatic lymph nodes was approximately 61% in patients who underwent a curative operation. Patients who received non-curative operation showed a certain efficacy to some extent. Twenty-one cases were judged as "S2" at operation. 11 cases as "se", and another 10 cases as 2 cases of "ss beta" and 8 cases of "pm" Histologically . Seven cases of "pm" were considered either as "good" or Histological efficacy as "++" in terms of macroscopical efficacy.

Adult↗
PubMed1983

Dynamics of cardiac output and systolic time intervals in supine and upright exercise.

Transient and steady-state responses of stroke volume (SV), heart rate (HR), cardiac output (Q), left ventricular ejection time (LVET), preejection period (PEP), and the ratio of LVET to PEP during bicycle exercises of 50 and 100 W were studied in four healthy male subjects in supine and upright postures. A computer-based system in which impedance cardiography was incorporated served to determine the above parameters on a 10-s interval basis. SV remained almost unchanged in response to exercises in a supine posture, whereas it increased significantly in an upright posture, although the individual differences among subjects were found to be large. The half-response times of variables to a step work load were determined. An approximate accordance was observed among the response times for HR, Q, and LVET/PEP. There was an inverse relationship between LVET and HR, the slope of which was found to be steeper in the supine posture than in the upright posture, reflecting the difference between the SV responses in both postures. LVET fell shortly after the cessation of exercise despite the decreasing HR. Inasmuch as the paradoxical reduction of LVET was also found in the case where SV remained unchanged in response to exercise, no changes in SV can be the cause thereof. Thus, a transient increase in ejection rate, which is due to either the increased myocardial contractility or decreased peripheral vascular resistance, may be responsible for the phenomenon.

Adult↗
PubMed1983

Cardiorespiratory dynamics during sinusoidal and impulse exercise in man.

Dynamic characteristics of ventilation, cardiac output, and gas exchange during sinusoidally varying work rates for the periods from 1 to 12 min and impulse work rate with a duration of 10 sec were studied on five healthy men in an upright position. Changes in work rate were given by controlling externally the electromagnetic braking system of a bicycle ergometer. Stroke volume, heart rate, and cardiac output during exercise were determined continuously by using an automated impedance cardiograph. Breath by breath determination in minute ventilation, respiratory frequency, tidal volume, oxygen consumption, carbon dioxide output, end-tidal pressures of oxygen and carbon dioxide, and gas exchange ratio were conducted. From these and steady-state response data amplitude and phase relations between each variable and the input work loads were obtained utilizing the frequency analysis techniques. The response characteristics to sinusoidal stimuli were well represented by first-order models with time constants for VE, VCO2, VO2, and Q averaging 75, 67, 52, and 36 sec, respectively. The kinetics of HR closely resembled that of Q. There was a close link between both the dynamics of VE and VCO2. On the other hand, the responses to impulse stimuli were better described by second-order models in which fast and slow response components were connected in parallel. However, the contribution of the fast component to total response was small. Although this response may support in its form the neuro-humoral concept to explain exercise hyperpnea, a tight linkage was observed between VE and VCO2 responses to impulse stimuli. Thus, hyperpnea during the unsteady-state of exercise may be explained by the cardiodynamic hypothesis.

Adult↗