Publications by authors named "Riki Hirata"

Decrease in white blood cell (WBC), neutrophil or platelet (PLT) count due to treatment with gemcitabine (GEM) is a dose-limited factor (DLF). Even for cases that satisfy the standard criteria for initiation of GEM therapy, the scheduled therapy is reportedly occasionally discontinued because of decreased PLT or WBC count. Here, a retrospective study was made to predict the factor causing discontinuation of GEM treatment before its first administration.

View Article and Find Full Text PDF

Paclitaxel (PTX) injection is presently used for various types of cancer therapy. Because PTX is an insoluble medicine, alcohol is included. Therefore, after PTX administration, the breath alcohol concentration (BAC) detected is reported.

View Article and Find Full Text PDF

Hippocampal long-term potentiation (LTP) is suppressed not only by stress paradigms but also by low frequency stimulation (LFS) prior to LTP-inducing high frequency stimulation (HFS; tetanus), termed metaplasticity. These synaptic responses are dependent on N-methyl-D-aspartate receptors, leading to speculations about the possible relationship between metaplasticity and stress-induced LTP impairment. However, the functional significance of metaplasticity has been unclear.

View Article and Find Full Text PDF

Several lines of evidence have shown that exposure to stress impairs long-term potentiation (LTP) in the CA1 field of the hippocampus, but the detailed mechanisms for this effect remain to be clarified. The present study elucidated the synaptic mechanism of stress-induced LTP suppression in conscious, freely moving rats using electrophysiological approaches. Open field stress (i.

View Article and Find Full Text PDF

Fear extinction is hypothesized to be a learning process based on a new inhibitory memory. The present study was conducted to elucidate the effect of early postnatal stress on the extinction of context-dependent fear memory in adult rats, with a focus on the serotonergic system. Extinction was estimated by the expression of freezing behavior during repeated extinction trials (i.

View Article and Find Full Text PDF

Synaptic plasticity expressed as long-term potentiation (LTP) in the hippocampal-medial prefrontal cortex (mPFC) pathway is considered to be involved in cognitive function and learning and memory processes, but its synaptic mechanism remains unknown. The present study characterized LTP in the mPFC using the atypical antipsychotic clozapine, with a focus on dopaminergic modulation. The magnitude of LTP was facilitated by pretreatment with clozapine (20 mg/kg, i.

View Article and Find Full Text PDF

Naringin (NG), a flavonoid in grapefruit and citrus, has been reported to exhibit antioxidant effects and pharmacological actions. Recently, we have reported that NG suppressed the cytotoxicity and apoptosis induced by H(2)O(2), a typical pro-oxidant, in mouse leukemia P388 cells. Cytosine arabinoside (1-beta-d-arabinofuranosylcytosine; Ara-C) is the most important antimetabolite chemotherapeutic drug used for acute leukemia.

View Article and Find Full Text PDF