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Biomedical subjects

Akira Ishida

Publications and source records attributed to Akira Ishida.

At least 19 recordsLinked to original sources
PubMed2006

Intraventricular ascorbic acid administration decreases hypoxic-ischemic brain injury in newborn rats.

Neuronal cell damage following hypoxic-ischemic (HI) brain injury is partly caused by production of free radicals and reactive oxygen species (ROS). Ascorbic acid (AA) is a potent antioxidant, which scavenges various types of ROS. Some studies have shown that it is neuroprotective, however, the issue is still controversial. In this study, we examined the effect of intraventricular AA administration on immature HI brain using the Rice-Vannucci model. After unilateral carotid artery ligation under isoflurane anesthesia, 7-day-old rat pups received varying concentrations of AA (0.04, 0.2, 1 and 5 mg/kg) by intraventricular injection and were exposed to 8% oxygen for 90 min. Vehicle controls received an equal volume of phosphate saline buffer. We assessed the neuroprotective effect of AA at 7 days post-HI. The percent brain damage measured by comparing the wet weight of the ligated side of hemisphere with that of contralateral one was reduced in both 1 and 5 mg/kg groups but not in either 0.04 or 0.2 mg/kg groups compared to vehicle controls (5 mg/kg 16.0 +/- 4.3%, 1 mg/kg 10.9 +/- 5.0%, vs. controls 36.7 +/- 3.6%, P < 0.05). Macroscopic evaluation of brain injury revealed the neuroprotective effect of AA in both 1 and 5 mg/kg groups (5 mg/kg 1.1 +/- 0.4, 1 mg/kg 0.4 +/- 0.3, vs. controls 2.9 +/- 0.3, P < 0.05). Western blots of fodrin on the ligated side also showed that AA significantly suppressed 150/145-kDa bands of fodrin breakdown products, which suggested that AA suppressed activation of calpain. Neuropathological quantitative analysis of cell death revealed that 1 mg/kg of AA injection significantly reduced the number of necrotic cells in cortex, caudate putamen, thalamus and hippocampus CA1, whereas that of apoptotic cells was only reduced in cortex. These findings show that intraventricular AA injection is neuroprotective after HI in immature rats.

Analysis of Variance↗
PubMed2005

Ketamine-induced apoptosis in cultured rat cortical neurons.

Recent data suggest that anesthetic drugs cause neurodegeneration during development. Ketamine is frequently used in infants and toddlers for elective surgeries. The purpose of this study is to determine whether glycogen synthase kinase-3 (GSK-3) is involved in ketamine-induced apoptosis. Ketamine increased apoptotic cell death with morphological changes which were characterized by cell shrinkage, nuclear condensation or fragmentation. In addition, insulin growth factor-1 completely blocked the ketamine-induced apoptotic cell death. Ketamine decreased Akt phosphorylation. GSK-3 is known as a downstream target of Akt. The selective inhibitors of GSK-3 prevented the ketamine-induced apoptosis. Moreover, caspase-3 activation was accompanied by the ketamine-induced cell death and inhibited by the GSK-3 inhibitors. These results suggest that activation of GSK-3 is involved in ketamine-induced apoptosis in rat cortical neurons.

Anesthetics, Dissociative↗
PubMed2005

Both regulatory T cells and antitumor effector T cells are primed in the same draining lymph nodes during tumor progression.

The peripheral tolerance mechanism prevents effective antitumor immunity, even though tumor cells possess recognizable tumor-associated Ags. Recently, it has been elucidated that regulatory T cells (Treg) play a critical role in maintaining not only self-tolerance, but also tolerance of tumor cells. However, because the Treg that maintain self-tolerance arise naturally in the thymus and are thought to be anergic in peripheral, it is still unclear where and when Treg for tumor cells are generated. In this study we analyze tumor-draining lymph nodes (LNs) and demonstrate that both antitumor effector T cells and Treg capable of abrogating the antitumor reactivity of the effector T cells are primed in the same LNs during tumor progression. The regulatory activity generated in tumor-draining LNs exclusively belonged to the CD4(+) T cell subpopulation that expresses both CD25 and a high level of CD62L. Forkhead/winged helix transcription factor gene expression was detected only in the CD62L(high)CD4(+)CD25(+) T cells. CD62L(high)CD4(+)CD25(+) Treg and CD62L(low)CD4(+)CD25(+) T cells, which possess effector T cell functions, had comparable expression of LFA-1, VLA-4, CTLA-4, lymphocyte activation gene-3, and glucocorticoid-induced TNFR. Thus, only CD62L expression could distinguish regulatory CD4(+)CD25(+) cells from effector CD4(+)CD25(+) cells in draining LNs as a surface marker. The Treg generated in tumor-draining LNs possess the same functional properties as the Treg that arise naturally in the thymus but recognize tumor-associated Ag. CD62L(high)CD4(+)CD25(+) Treg contained a subpopulation that expressed CD86. Blocking experiments revealed that ligation of CTLA-4 on effector T cells by CD86 on Treg plays a pivotal role in regulating CD4(+) effector T cells.

Animals↗
PubMed2005

In vitro and in vivo antitumor activity of the NF-kappaB inhibitor DHMEQ in the human T-cell leukemia virus type I-infected cell line, HUT-102.

Adult T-cell leukemia (ATL) is an aggressive neoplasm caused by human T-cell leukemia virus type I (HTLV-I). The NF-kappaB pathway is activated in ATL cells and in virus-infected cells, and plays a central role in oncogenesis. We examined the effect of the novel NF-kappaB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ), on a well-characterized HTLV-I-infected cell line, HUT-102, in vitro and in vivo. DHMEQ inhibited translocation of NF-kappaB p65 to the nucleus and induced apoptotic cell death in vitro. In vivo, DHMEQ inhibited the growth and infiltration of HUT-102 tumor cells transplanted subcutaneously in SCID mice lacking natural killer cell activity.

Active Transport, Cell Nucleus↗
PubMed2005

In vivo antitumor activity of the NF-kappaB inhibitor dehydroxymethylepoxyquinomicin in a mouse model of adult T-cell leukemia.

Adult T-cell leukemia (ATL) is an aggressive neoplasm caused by human T-cell leukemia virus type I (HTLV-I). The nuclear transcription factor, NF-kappaB, is induced by HTLV-I and is central to the ensuing neoplasia. To examine the effect of a novel NF-kappaB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ), on ATL in vivo, we developed an improved severe combined immunodeficiency (SCID) mouse model for ATL. Five-week-old SCID mice in which natural killer (NK) cell activity had been eliminated were inoculated intraperitoneally with the HTLV-I-infected cell lines, TL-Om1, MT-1, MT-2 and HUT-102. No engraftment of TL-Om1 cells and little tumorigenesis of MT-1 cells were detected 40 days after injection. In contrast, inoculation of mice with MT-2 and HUT-102 cells elicited high mortality, 100% frequency of gross tumor formation and tumor cell infiltration of various organs, all of which were reduced by coadministration of DHMEQ during the inoculation. Moreover, tumors from mice treated with DHMEQ had a high frequency of apoptosis. These results suggest that DHMEQ induces apoptosis in HTLV-I-transformed cells in vivo, resulting in inhibition of tumor formation and organ infiltration, thereby enhancing survival.

Animals↗
PubMed2005

Calpain inhibitor MDL 28170 protects hypoxic-ischemic brain injury in neonatal rats by inhibition of both apoptosis and necrosis.

MDL 28170 is a CNS-penetrating calpain inhibitor, and we examined the effects of MDL 28170 on hypoxic-ischemic brain injury in immature brain using the Rice-Vannucci model. Immediately after hypoxic exposure, 24 mg/kg of MDL 28170 was injected intraperitoneally as an initial dose, followed by 12 mg/kg every 4 h for a total dose of 60 mg/kg over 12 h post-HI. A vehicle control group received peanut oil injection instead. Macroscopic evaluation of brain injury revealed the neuroprotective effect of MDL 28170 after 12 h post-HI. Neuropathological quantitative analysis of cell death showed that MDL 28170 significantly decreased the number of necrotic cells in all the examined regions except for cingular cortex, and the number of apoptotic cells in caudate putamen, parietal cortex, hippocampus CA1, and laterodorsal thalamus. Western blots showed that MDL 28170 suppressed 145/150 kDa subunits of alpha-spectrin breakdown products (SBDP) in cortex, hippocampus, thalamus, and striatum, and also 120-kDa subunit of SBDP in all regions except for striatum. This suggests that MDL 28170 inhibited activation of calpain and caspase-3, respectively. Our results indicate that post-hypoxic MDL 28170 injection is neuroprotective in HI newborn rat brain by decreasing both necrosis and apoptosis. SBDP expression also suggests that MDL 28170 injection inhibits both calpain and caspase-3 activation after HI insult.

Animals↗
PubMed2005

Prolonged hypothermia protects neonatal rat brain against hypoxic-ischemia by reducing both apoptosis and necrosis.

Although hypothermia is an effective treatment for perinatal cerebral hypoxic-ischemic (HI) injury, it remains unclear how long and how deep we need to maintain hypothermia to obtain maximum neuroprotection. We examined effects of prolonged hypothermia on HI immature rat brain and its protective mechanisms using the Rice-Vannucci model. Immediately after the end of hypoxic exposure, the pups divided into a hypothermia group (30 degrees C) and a normothermia one (37 degrees C). Rectal temperature was maintained until they were sacrificed at each time point before 72h post HI. Prolonged hypothermia significantly reduced macroscopic brain injury compared with normothermia group. Quantitative analysis of cell death using H&E-stained sections revealed the number of both apoptotic and necrotic cells was significantly reduced by hypothermia after 24h post HI. Hypothermia seemed to decrease the number of TUNEL-positive cells. Immunohistochemistry and Western blot showed that prolonged hypothermia suppressed cytochrome c release from mitochondria to cytosol and activation of both caspase-3 and calpain in cortex, hippocampus, thalamus and striatum throughout the experiment. These results showed that prolonged hypothermia significantly reduced neonatal brain injury even when it was started after HI insult. Our results suggest that prolonged hypothermia protects neonatal brain after HI by reducing both apoptosis and necrosis.

Animals↗
PubMed2005

Cerebral hemorrhage restricted to the corpus callosum.

We report a case of an 87-yr-old woman with hemorrhage restricted to the corpus callosum. After conservative treatment at an emergency hospital, she was admitted to our hospital presenting with bilateral lower limb weakness (paraparesis) and abnormal behavior in her left hand, such as pulling at dishes while eating and purposeless "floating" of the hand while walking. We believed these behaviors to represent disconnection syndrome. Six weeks after onset, her abnormal behavior while eating disappeared. The incomplete paraparesis also improved, and she regained the ability to walk, albeit with a T cane. These findings are compatible with previously reported cases. In cases of a corpus callosum lesion, careful observation from the outset is indispensable to avoid misdiagnosis.

Aged↗
PubMed2005

Development of a new mouth opening force test using an indirect cervical traction device.

BACKGROUND AND AIMS: There have been few reports of objective jaw opening tests, and such studies have involved devices specifically designed for research. In the present study, in order to conveniently and objectively assess mouth opening movements, we replaced the manual resistance used in Daniels and Worthingham's muscle test (DMT) with an indirect cervical traction device. We examined whether the maximum mouth opening force (MOF) could be reliably quantified using this device. METHODS: The subjects were 12 healthy individuals with a mean age of 28.8 years. The MOF measurement procedure was as follows: 1) the subject sat in the chair, and a head belt was placed under the chin so that a traction force was applied almost parallel to the body axis; 2) the researcher instructed the subject to maintain the maximum mouth opening; 3) as maximum resistance was approached, the rate of increase in the traction force decreased. Maximum opening force was recorded; 4) one measurement was taken per session, for a total of two measurements per subject. Pearson's correlation coefficients were used to assess the reproducibility of MOF values. RESULTS: The average MOF (mean +/- SD) in the first and second tests was 24.2 +/- 1.9 and 24.5 +/- 2.0 kg. There was an extremely high correlation between first and second measurements (r = 0.969). CONCLUSIONS: The presently described indirect cervical traction device can be used to reliably quantify MOF.

Adult↗
PubMed2004

Dexamethasone-induced prenatal alveolar wall thinning is associated with a decrease in EIIIA+ fibronectin isoform in the fetal rat lung.

BACKGROUND: Glucocorticoid hormones play an important role in architectural and biochemical lung maturation. Although much of the molecular mechanism of their action in the lung is not fully understood, glucocorticoids directly or indirectly regulate lung maturation. Indirect effects of glucocorticoids may involve the modulation of cell-cell or cell-matrix interactions. Fibronectin (FN) is the major constituent of the pulmonary extracellular matrix and exists in multiple isoforms arising from alternative RNA splicing. EIIIA is the major alternatively spliced segment, and its expression is regulated in a spatiotemporal and oncodevelopmental manner. OBJECTIVES: The present study focuses on the regulation of EIIIA-containing FN isoforms (referred to as EIIIA+ FN) by glucocorticoids in the developing lung. METHODS: Dexamethasone (DEX) or saline was injected daily into pregnant rats from day 15 of gestation (term = day 22) until 24 h before sacrifice. The expression of EIIIA+ FN and proliferating cell nuclear antigen (PCNA), a biochemical marker for cell proliferation, was investigated in the fetal rat lung. RESULTS: At day 20 of gestation (the canalicular stage), the DEX-treated lung showed a significant decrease in weight and saccular septal wall thickness, while the messenger RNA expression of the surfactant protein SP-B was increased in the DEX-treated lung, as compared with the control lung. The expression of EIIIA+ FN and PCNA around the distal airspaces was less extensive in the DEX-treated lung than in the control lung at day 20 of gestation. CONCLUSIONS: Given the finding in vitro that EIIIA+ FN regulated the cell cycle, our results suggest that the change of EIIIA+ FN expression in the DEX-treated lung affected pulmonary cell proliferation.

Alternative Splicing↗
PubMed2004

Neuroprotection of edaravone on hypoxic-ischemic brain injury in neonatal rats.

Edaravone has an inhibitory effect on lipid peroxidation by scavenging free radicals and prevents vascular endothelial cell injury. We examined whether edaravone was effective on hypoxic-ischemic (HI) brain injury in immature brain or not using the Rice-Vannucci model. The initial dose, 3 mg/kg (0.05 ml) of edaravone, was injected intraperitoneally just before hypoxic exposure. Subsequently, the same dose was injected every 12 h until the animals were killed. Controls received saline injection as the same protocol. Macroscopic evaluation of brain injury revealed that the neuroprotective effect of edaravone on HI brain after 48 h post HI. TUNEL showed that edaravone injection decreased neurodegeneration. Quantitative analysis of cell death using H&E-stained 2.5 microm sections showed that there was a trend for both necrotic and apoptotic cells to decrease in edaravone injection group. Edaravone injection inhibited the release of cytochrome c from mitochondria to cytosol and caspase-3 activation in cortex and hippocampus between 24 and 168 h post HI. Our results suggest that edaravone is protective after HI insult in the immature brain by decreasing both apoptosis and necrosis and also by inhibiting mitochondrial injury.

Animals↗
PubMed2004

Development of immunocapture reverse transcription loop-mediated isothermal amplification for the detection of tomato spotted wilt virus from chrysanthemum.

An immunocapture reverse transcription loop-mediated isothermal amplification (IC/RT-LAMP) was developed for the detection of tomato spotted wilt virus (TSWV) from chrysanthemum. This method enabled sensitive, reproducible and specific detection of TSWV from chrysanthemum plants. In the RT-LAMP method, TSWV genomic RNA could be amplified under isothermal (65 degrees C) conditions within 1 h. The resulting amplicons were detected by the measurement or observation of the turbidity of the reaction mixture without gel electrophoresis. IC/RT-LAMP was 100 times more sensitive than IC/RT-PCR.

Base Sequence↗
PubMed2004

Good outcome for infant of mother treated with chemotherapy for ewing sarcoma at 25 to 30 weeks' gestation.

There have been only three previous reports of women with Ewing sarcoma who received chemotherapy while pregnant. A 17-year-old woman with Ewing sarcoma was treated with a combination of doxorubicin (Adriamycin) and ifosfamide during the 25th to 30th week of gestation, and the baby was delivered at the 32nd week. The baby was developing normally at follow-up at 8 months of age. This case report supports the idea that in this situation, the pregnancy can be continued to await fetal growth, and second-trimester chemotherapy may not have a deleterious effect on the fetus.

Adolescent↗
PubMed2003

Intermanual difference in the Japanese Trail Making Test and its mirror version: intra-subject comparison of the task-completion time, cognitive time, and motor time.

PURPOSE: To investigate intermanual differences in the performance of the Japanese Trail Making Test (JTMT) using an intra-subject comparison, and to investigate how the cognitive and motor times spent in performing the task were related with the total completion time. METHODS: All subjects performed both parts A and B of the following three tasks: JTMT with the right hand (R); JTMT with the left hand (L); and a mirror version of the JTMT with the left hand (M). The order in which these three tasks were performed (RLM, RML, LRM, LMR, MRL, and MLR) was randomly determined. An interval of 4 weeks was scheduled between each examination. In addition to the completion time, we measured 'motor time', a sum of the times for drawing lines to connect the targets, and 'cognitive time', a time obtained by subtracting the motor time from the completion time. RESULTS: The task-completion time was more strongly correlated with the cognitive time than with the motor time. The order of the task performance did not influence the task-completion time. A learning effect was found only between the first and second examinations of part A. The cognitive time for the second and third performances of part A were significantly shorter than that for the first task, whereas the motor time remained unchanged. No intermanual differences in the performance were found in any comparisons. CONCLUSIONS: The non-dominant hand can be used as an alternative hand in the JTMT, and it can be expected to perform comparably to the dominant hand. These findings are consistent with the finding previously obtained by inter-subject comparison. The lack of any significant intermanual difference can be explained by that the total completion time is less influenced by the motor time than by the cognitive time.

Adult↗
PubMed2003

Nondominant hand performance of the Japanese Trail Making Test and its mirror version.

OBJECTIVES: To investigate intermanual differences in the Japanese version of the Trail Making Test (JTMT) and to investigate whether a mirror version of the JTMT test sheet (JTMT-M) should be used when the task is performed with the nondominant hand. DESIGN: Intermanual differences were compared among the JTMT with the dominant hand, the JTMT with the nondominant hand, and the JTMT-M with the nondominant hand. SETTING: Rehabilitation center in a university hospital. PARTICIPANTS: A total of 150 persons (age range, 19-38y) who had no history of neurologic or musculoskeletal impairment. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: The time to complete the task. RESULTS: Nondominant hand performance on the JTMT and JTMT-M did not differ significantly from that of the dominant hand on the JTMT. All left hand data except 1 in each task were within the previously reported reference values obtained from the JTMT with the right hand. CONCLUSIONS: The nondominant hand can be used as an alternative in the JTMT and can be expected to perform comparably to the dominant hand. There is no need to use the JTMT-M even when the task is conducted with the nondominant hand.

Adult↗
PubMed2003

Detection of tomato yellow leaf curl virus by loop-mediated isothermal amplification reaction.

The genomic DNA molecule of tomato yellow leaf curl virus (TYLCV), a whitefly-transmitted geminivirus, was amplified from total DNA extracts of TYLCV-infected tomato (Lycopersicon esculentum) by the use of loop-mediated isothermal amplification (LAMP). The procedure was also used to amplify TYLCV DNA from total DNA extracts of individual whiteflies (Bemisia tabaci) that had fed on TYLCV-infected plants. One of the characteristics of the LAMP method is its ability to synthesize an extremely large amount of DNA. Accordingly, a large amount of by-product, pyrophosphate ion, is produced yielding a white precipitate of magnesium pyrophosphate in the reaction mixture. The presence or absence of this white precipitate allows easy detection of amplification of TYLCV genomic DNA without gel electrophoresis.

Amino Acid Sequence↗