Copy number loss of KDM5D may be a predictive biomarker for ATR inhibitor treatment in male patients with pulmonary squamous cell carcinoma.

A limited number of patients with lung squamous cell carcinoma (SCC) benefit clinically from molecular targeted drugs because of a lack of targetable driver alterations. We aimed to understand the prevalence and clinical significance of lysine-specific demethylase 5D (KDM5D) copy number loss in SCC and explore its potential as a predictive biomarker for ataxia-telangiectasia and Rad3-related (ATR) inhibitor treatment. We evaluated KDM5D copy number loss in 173 surgically resected SCCs from male patients using fluorescence in situ hybridization. KDM5D copy number loss was detected in 75 of the 173 patients (43%). Genome-wide expression profiles of the transcription start sites (TSSs) were obtained from 17 SCCs, for which the cap analysis of gene expression assay was performed, revealing that upregulated genes in tumors with the KDM5D copy number loss are associated with 'cell cycle', whereas downregulated genes in tumors with KDM5D copy number loss were associated with 'immune response'. Clinicopathologically, SCCs with KDM5D copy number loss were associated with late pathological stage (p = 0.0085) and high stromal content (p = 0.0254). Multiplexed fluorescent immunohistochemistry showed that the number of tumor-infiltrating CD8+ /T-bet+ T cells was lower in SCCs with KDM5D copy number loss than in wild-type tumors. In conclusion, approximately 40% of the male patients with SCC exhibited KDM5D copy number loss. Tumors in patients who show this distinct phenotype can be 'cold tumors', which are characterized by the paucity of tumor T-cell infiltration and usually do not respond to immunotherapy. Thus, they may be candidates for trials with ATR inhibitors.

Multiple Small Bowel Gastrointestinal Stromal Tumors Associated with Neurofibromatosis Type 1 that Were Not Detected by Endoscopy: A Case Report.

We treated a 39-year-old Japanese man who was admitted for an abdominal mass. He had had neurofibroma-like skin lesions since childhood. Computed tomography and endoscopic ultrasound results were consistent with a tumor in the small intestine. Although the tumor was undetectable by single-balloon endoscopy, the patient's background and imaging results led us to suspect a gastrointestinal stromal tumor (GIST). He also met the diagnostic criteria for neurofibroma type 1 (NF1). We performed a surgical removal of the tumor, and the biopsy results led to a definitive diagnosis of GIST. Small bowel GISTs should be considered in cases of NF1.

Transcription start site-level expression of thyroid transcription factor 1 isoforms in lung adenocarcinoma and its clinicopathological significance.

There are multiple transcription start sites (TSSs) in agreement with multiple transcript variants encoding different isoforms of NKX2-1/TTF-1 (thyroid transcription factor 1); however, the clinicopathological significance of each transcript isoform of NKX2-1/TTF-1 in lung adenocarcinoma (LAD) is unknown. Herein, TSS-level expression of NKX2-1/TTF-1 isoforms was evaluated in 71 LADs using bioinformatic analysis of cap analysis of gene expression (CAGE)-sequencing data, which provides genome-wide expression levels of the 5'-untranslated regions and the TSSs of different isoforms. Results of CAGE were further validated in 664 LADs using in situ hybridisation. Fourteen of 17 TSSs in NKX2-1/TTF-1 (80% of known TSSs in FANTOM5, an atlas of mammalian promoters) were identified in LADs, including TSSs 1-13 and 15; four isoforms of NKX2-1/TTF-1 transcripts (NKX2-1_001, NKX2-1_002, NKX2-1_004, and NKX2-1_005) were expressed in LADs, although NKX2-1_005 did not contain a homeodomain. Among those, six TSSs regulated NKX2-1_004 and NKX2-1_005, both of which contain exon 1. LADs with low expression of isoforms from TSS region 11 regulating exon 1 were significantly associated with poor prognosis in the CAGE data set. In the validation set, 62 tumours (9.3%) showed no expression of NKX2-1/TTF-1 exon 1; such tumours were significantly associated with older age, EGFR wild-type tumours, and poor prognosis. In contrast, 94 tumours, including 22 of 30 pulmonary invasive mucinous adenocarcinomas (IMAs) exhibited exon 1 expression without immunohistochemical TTF-1 protein expression. Furthermore, IMAs commonly exhibited higher exon 1 expression relative to that of exon 4/5, which contained a homeodomain in comparison with EGFR-mutated LADs. These transcriptome and clinicopathological results reveal that LAD use at least 80% of NKX2-1 TSSs and expression of the NKX2-1/TTF-1 transcript isoform without exon 1 (NKX2-1_004 and NKX2-1_005) defines a distinct subset of LAD characterised by aggressive behaviour in elder patients. Moreover, usage of alternative TSSs regions regulating NKX2-1_005 may occur in subsets of LADs.

Development of glycated peptide enzyme sensor based flow injection analysis system for haemoglobin A1c monitoring using quasi-direct electron transfer type engineered fructosyl peptide oxidase.

Haemoglobin A1c (hemoglobin A1c, HbA1c) is an important long-term glycemic control marker for diabetes. The aim of this study was to develop an enzyme flow injection analysis (FIA) system using engineered fructosyl peptide oxidase (FPOx) based on 2.5th generation principle for an HbA1c automated analytical system. FPOx from Phaeosphaeria nodorum (PnFPOx) was engineered by introducing a Lys residue at the R414 position, to be modified with amine reactive phenazine ethosulfate (arPES) in proximity of FAD. The engineered PnFPOx mutant with minimized oxidase activity, N56A/R414K, showed quasi-direct electron transfer (quasi-DET) ability after PES-modification. The FIA system was constructed by employing a PES-modified PnFPOx N56A/R414K and operated at 0 V against Ag/AgCl. The system showed reproducible responses with a linear range of 20-500 µM for both fructosyl valine (FV) and fructosyl valylhistidine (FVH), with sensitivities of 0.49 nA µM-1 and 0.13 nA µM-1, and the detection limits of 1.3 µM and 2.0 µM for FV and FVH, respectively. These results indicate that the enzyme electrochemical FIA system covers the clinical range of HbA1c detection for more 200 consecutive measurements. Protease digested three different levels of HbA1c samples including healthy and diabetic range subjects were also measured with the FIA system. Thus, it will be possible to develop an integrated system consisting of sample pretreatment and sample electrochemical measurement based on an FIA system possessing quasi-DET type PnFPOx.

A case of hemorrhage of hepatocellular carcinoma resembling a hepatic cyst arising from non-cirrhotic steatohepatitis.

A 70-year-old female was found to have multiple hepatic cysts at her annual checkup. In the posterior segment of the right lobe of the liver, an 81 × 67 mm circular cystic lesion was detected by contrast-enhanced computed tomography (CT). Magnetic resonance imaging (MRI) of the cyst revealed a solid component. The cyst had a capsule-like structure and non-uniform fluid accumulation suggested bleeding. Since the lesion was enlarged and malignancy could not be ruled out, it was surgically resected. Histopathologically, reticular fibers of the liver were seen in necrotic tissue and the lesion was diagnosed as a bleeding hepatocellular carcinoma (HCC). The non-cancerous liver tissue showed non-cirrhotic steatohepatitis. This was an unusual presentation of HCC.

The Efficacy of Medium- to Long-term Anti-TNF-α Antibody-based Maintenance Therapy in Behçet's Disease Patients with Intestinal Lesions.

Objective Anti-tumor necrosis factor (TNF)-α antibody-based regimens are effective in Behçet's disease (BD) with intestinal lesions. We therefore evaluated the efficacy of medium- to long-term anti-TNF-α antibody-based maintenance therapy of BD intestinal and non-intestinal lesions. Methods In this retrospective study, the response to the treatment was assessed endoscopically and clinically. Treatment responders were transferred to maintenance therapy. We evaluated the sustain rate of maintenance therapy, reductions in the dose of prednisolone (PSL), and the presence of non-intestinal BD involvement before and after the start of anti-TNF-α antibody-based the maintenance therapy. Patients We assessed 20 BD patients with intestinal lesions who underwent anti-TNF-α antibody-based therapy. Results Treatment was discontinued in 3 patients (18%). Loss of response was noted in 1 (5.9%) patient. Maintenance therapy was continued in 13 (76%) patients. The cumulative sustain rates to maintenance therapy after 2, 4, and 6 years were 94%, 87%, and 72%, respectively. In the 13 patients with remission of intestinal lesions, the mean PSL dose decreased from 13.4±2.16 mg/day before treatment to 0.92±0.47 after treatment (p<0.0001). PSL was discontinued in 9 (69%) patients. Five of the 13 (38%) patients developed clinical features of non-intestinal BD during the remission-maintenance treatment. Conclusion Our results demonstrated the efficacy of medium- to long-term anti-TNF-α antibody-based maintenance treatment against BD intestinal lesions. Nevertheless, some cases with well-controlled intestinal lesions developed active non-intestinal BD symptoms. The results highlight the importance of a carefully planned treatment strategy for BD patients with intestinal involvement.

Bifidobacteria in two-toed sloths (Choloepus didactylus): phylogenetic characterization of the novel taxon Bifidobacterium choloepi sp. nov.

Seven bifidobacterial strains were isolated from the faeces of two adult males of the two-toed sloth (Choloepus didactylus) housed in Parco Natura Viva, in Italy. Comparative sequence analysis of 16S rRNA and of five housekeeping (hsp60, rpoB, clpC, dnaJ, dnaG) genes revealed that these strains were classified into two clusters. On the basis of 16S rRNA gene sequence similarity, the type strain of Bifidobacterium catenulatum subsp. kashiwanohense DSM 21854T (95.4 %) was the closest neighbour to strain in Cluster I (BRDM 6T), whereas the type strain of Bifidobacterium dentium DSM 20436T (values were in the range of 98‒99.8 %) was the closest neighbour to the other six strains in Cluster II. The average nucleotide identity (ANI) values of BRDM 6T and of strains in Cluster II with the closely related type strains were 76.0 and 98.9 % (mean value) respectively. Therefore, genotyping based on the genome sequence of the strain BRDM 6T combined with phenotypic analyses clearly revealed that the strain BRDM 6T represents a novel species for which the names Bifidobacterium choloepi sp. nov. (BRDM 6T=NBRC 114053T=BCRC 81222T) is proposed.

Phylogenetic characterization of two novel species of the genus Bifidobacterium: Bifidobacterium saimiriisciurei sp. nov. and Bifidobacterium platyrrhinorum sp. nov.

Three bifidobacterial Gram-stain-positive, non-spore forming and fructose-6-phosphate phosphoketolase-positive strains, SMA1T, SMB2 and SMA15T were isolated from the faeces of two adult males of the squirrel monkey (Saimiri sciureus). On the basis of 16S rRNA gene sequence similarities, the type strain of Bifidobacterium primatium DSM 100687T (99.3%; similarity) was the closest neighbour to strains SMA1T and SMB2, whereas the type strain of Bifidobacterium stellenboschense DSM 23968T (96.5%) was the closest neighbour to strain SMA15T. The average nucleotide identity (ANI) values of SMA1T and SAM15T with the closely related type strains were 93.7% and 88.1%, respectively. The in silico DNA‒DNA hybridization values with the closest neighbours were 53.1% and 36.9%, respectively. GC contents of strains SMA1T and SMA15T were 63.6 and 66.4 mol%, respectively. Based on the phylogenetic, genotypic and phenotypic data obtained, the strains SMA1T and SMA15T clearly represent two novel taxa within the genus Bifidobacterium for which the names Bifidobacterium saimiriisciurei sp. nov. (type strain SMA1T = BCRC 81223T = NBRC 114049T = DSM 106020T) and Bifidobacterium platyrrhinorum sp. nov. (type strain SMA15T = BCRC 81224T = NBRC 114051T = DSM 106029T) are proposed.

Gordonia crocea sp. nov. and Gordonia spumicola sp. nov. isolated from sludge of a wastewater treatment plant.

Two novel actinobacteria, designated NBRC 107696T and NBRC 107697T, were isolated from sludge samples from a wastewater treatment plant and their taxonomic positions were investigated by a polyphasic approach. The cells of the strains were aerobic, rod-shaped, non-motile and non-endospore-forming. The strains contained glutamic acid, alanine and meso-diaminopimelic acid in the peptidoglycan. Galactose and arabinose were detected as cell-wall sugars. The predominant menaquinone was identified as MK-9(H2) and the major fatty acids were C16  :  0, C18 : 1ω9c and C16 : 1ω7c. The DNA G+C contents of NBRC 107696T and NBRC 107697T were 68.07 and 68.99 mol%, respectively. Phylogenetic analyses based on 16S rRNA gene sequence comparisons revealed that NBRC 107696T and NBRC 107697T were a clade with members of the genus Gordonia. The highest 16S rRNA gene sequence similarity values were obtained with Gordonia araii IFM 10211T (98.9 %) for NBRC 107697T, and Gordonia malaquae IMMIB WWCC-22T, Gordonia neofelifaecis AD-6T and Gordonia humi CC-12301T (98.1 %) for NBRC 107696T, respectively. The digital DNA-DNA relatedness data coupled with the combination of genotypic and phenotypic data indicated that the two strains are representatives of two novel separate species. The names proposed to accommodate these two strains are Gordonia spumicola sp. nov. and Gordonia crocea sp. nov., and the type strains are NBRC 107696T (=IFM 10067T=TBRC 11239T) and NBRC 107697T (=IFM 10881T=TBRC 11240T), respectively.

Atypical Sarcoidosis Diagnosed by Massive Splenomegaly.

We examined a 22-year-old woman who was admitted to our hospital with abdominal distention. At 19 years of age, the patient presented with hepatosplenomegaly. She was examined several times in another hospital; however, the cause was unidentified. Our evaluation showed severe pancytopenia and a spleen 13×24 cm in size. The serum levels of angiotensin-converting enzyme and lysozyme were elevated. She was diagnosed with liver sarcoidosis based on non-caseating epithelioid granuloma in liver biopsy tissue. To improve the symptoms, splenectomy was performed, and her pancytopenia and symptoms improved. Sarcoidosis should be considered in cases of massive splenomegaly.

Agromyces protaetiae sp. nov., isolated from gut of larva of Protaetia brevitarsis seulensis.

An actinobacterial strain, designated FW100M-8T, was isolated from a gut sample of larva of Protaetia brevitarsis seulensis at the National Institute of Agricultural Sciences, Wanju-gun, South Korea. Cells were Gram-stain-positive, microaerophilic to aerobic, non-spore forming and non-motile. It grew at pH 7.0-9.0 (optimum, pH 8.0), at 15-35 °C (optimum, 28 °C) and 0-3.0 % (w/v) NaCl (optimum, 0 %). According to the 16S rRNA gene analysis, strain FW100M-8T shared the highest sequence similarity with Agromyces mediolanus DSM 20152T (98.4 %), Agromyces ulmi XIL01T (98.3 %), Agromyces indicus NIO-1018T (98.3 %), Agromyces soli MJ21T (98.3 %), and Agromyces arachidis AK-1T (97.9 %). Phylogenetic trees showed that strain FW100M-8T fell into the lineage of the genus Agromyces. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, an unidentified glycolipid and an unidentified lipid. The menaquinones of strain FW100M-8T were MK-12 (46 %), MK-11 (36 %), MK-10 (14 %) and MK-13 (4 %). The major fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The peptidoglycan type was supposed to be the type B1, comprising d-Ala, d-Glu, Gly and l-A2bu. The G+C content of the genomic DNA is 70.5 mol%. On the basis of the genotypic and phenotypic data, we conclude that strain FW100M-8T represents a novel species of the genus Agromyces, for which the name Agromyces protaetiae sp. nov. is proposed with strain FW100M-8T (=KACC 19308T=NBRC 113048T) as the type strain.

Characterization of Bifidobacterium species in feaces of the Egyptian fruit bat: Description of B. vespertilionis sp. nov. and B. rousetti sp. nov.

Fifteen bifidobacterial strains were obtained from faeces of Rousettus aegyptiacus; after grouping them by RAPD PCR only eight were selected and characterized. Analysis of 16S rRNA and of five housekeeping (hsp60, rpoB, clpC, dnaJ, dna G) genes revealed that these eight strains were classified into five clusters: Cluster I (RST 8 and RST 16T), Cluster II (RST 9T and RST 27), Cluster III (RST 7 and RST 11), Cluster IV (RST 19), Cluster V (RST 17) were closest to Bifidobacterium avesanii DSM 100685T (96.3%), Bifidobacterium callitrichos DSM 23973T (99.2% and 99.7%), Bifidobacterium tissieri DSM 100201T (99.7 and 99.2%), Bifidobacterium reuteri DSM 23975 T (98.9%) and Bifidobacterium myosotis DSM 100196T (99.3%), respectively. Strains in Cluster I and strain RST 9 in Cluster II could not be placed within any recognized species while the other ones were identified as known species. The average nucleotide identity values between two novel strains, RST 16T and RST 9T and their closest relatives were lower than 79% and 89%, respectively. In silico DNA-DNA hybridization values for those closest relatives were 32.5 and 42.1%, respectively. Phenotypic and genotypic tests demonstrated that strains in Cluster I and RST 9T in Cluster II represent two novel species for which the names Bifidobacterium vespertilionis sp. nov. (RST 16T=BCRC 81138T=NBRC 113380T=DSM 106025T ; RST 8=BCRC 81135=NBRC 113377) and Bifidobacterium rousetti sp. nov. (RST 9T=BCRC 81136T=NBRC 113378T=DSM 106027T) are proposed.

First Detection of an Escherichia coli Strain Harboring the mcr-1 Gene in Retail Domestic Chicken Meat in Japan.

Global spread of the plasmid-mediated colistin resistance gene, mcr-1 poses a challenge to public health because colistin is the last-line-of-defense against severe infections of multidrug-resistant Gram-negative bacteria. In Japan, a few studies have reported the prevalence of mcr-1 among food animal-derived Escherichia coli isolates, but the prevalence of mcr-1 in retail meats is not well known. We report here the first detection of mcr-1 in retail chicken meat. A total of 70 extended-spectrum beta-lactamase-producing E. coli isolates, recovered from retail chicken meats between August 2015 and June 2016, were screened for mcr-1. We found 1 CTX-M-1 beta-lactamase-producing E. coli isolate belonging to ST1684, phylogroup A. The mcr-1 gene was not located on an IncI1 plasmid encoding the blaCTX-M-1 gene. However, whole plasmid sequencing revealed that mcr-1 was located on an IncI2 plasmid. The sequences of the nikB-mcr-1-pap2-ydfA-topB region of the IncI2 plasmid in this study was almost identical to that of the previously described IncI2 plasmid, pECJS-61-63 present in E. coli isolated from pig feces in China, except for containing a synonymous mutation in the mcr-1 gene. Plasmid carrying the mcr-1 gene have not yet been identified in human isolates in Japan. Thus, strict monitoring or surveillance of colistin resistance among Gram-negative bacteria recovered from retail meat of food animals under colistin pressure, and humans, is crucial.

Third-Generation Cephalosporin-Resistant Non-Typhoidal Salmonella Isolated from Human Feces in Japan.

ß-lactamase genes were detected and characterized from 10 non-typhoidal Salmonella (NTS) clinical isolates resistant to third-generation cephalosporins collected between 2012 and 2014 in Japan. Five strains showed cefotaxime minimum inhibitory concentration (MIC) ≥ 64 µg/ml and positive clavulanic acid inhibition results. The blaCTX-M-2 was detected in 3 strains (serotypes Stanley and Muenchen), whereas blaTEM-52 (serotype Manhattan) and blaSHV-12 (serotype Infantis) were each found in 1 strain. blaCMY-2 was detected in the remaining 5 strains (serotypes Infantis, Rissen, Newport, and Saintpaul) with cefotaxime MICs of 4-32 µg/ml and positive cloxacillin- and 3-aminophenylboronic acid- based inhibition tests. ISEcp1 was located upstream of the blaCMY-2 in 4 strains and of the blaCTX-M-2 in 1 strain. Incompatibility (Inc)A/C, IncP, and IncI1 plasmids were present in the strains harboring blaCMY-2, which were detected predominantly in this study. Acquisition of resistance to third-generation cephalosporins by invasive NTS may limit therapeutic options for severe systemic infections and causing serious public health problems. Though such resistant clinical isolates are still rare in Salmonella species in Japan, our findings reveal the presence of cephem-resistant NTS in food handlers, thus emphasizing the necessity of more systematic nationwide investigations.

Different profiles of quercetin metabolites in rat plasma: comparison of two administration methods.

The bioavailability of polyphenols in human and rodents has been discussed regarding their biological activity. We found different metabolite profiles of quercetin in rat plasma between two administration procedures. A single intragastric administration (50 mg/kg) resulted in the appearance of a variety of metabolites in the plasma, whereas only a major fraction was detected by free access (1% quercetin). The methylated/non-methylated metabolites ratio was much higher in the free access group. Mass spectrometric analyses showed that the fraction from free access contained highly conjugated quercetin metabolites such as sulfo-glucuronides of quercetin and methylquercetin. The metabolite profile of human plasma after an intake of onion was similar to that with intragastric administration in rats. In vitro oxidation of human low-density lipoprotein showed that methylation of the catechol moiety of quercetin significantly attenuated the antioxidative activity. These results might provide information about the bioavailability of quercetin when conducting animal experiments.

Immunochemical detection of flavonoid glycosides: development, specificity, and application of novel monoclonal antibodies.

Flavonoid-rich diets are expected to decrease the risk of cardiovascular diseases. The localization and target sites of flavonoids underlying the protective mechanism in vivo have not been fully investigated because the methods for detection of flavonoids have been limited to chemical analysis such as high-performance liquid chromatography. To further understand the actions of flavonoids in vivo, we developed a novel methodology that immunochemically evaluates flavonoids using specific antibodies. Quercetin-3-glucuronide (Q3GA), a major metabolite in human plasma, was coupled with keyhole limpet hemocyanin. Alternatively, the sugar moiety of quercetin-3-glucoside (Q3G) was succinylated and then coupled with a carrier protein. Using these two immunogens, we finally obtained two monoclonal antibodies, mAb14A2 and mAb11G6, from the immunogen using Q3GA and Q3G, respectively. Competitive enzyme-linked immunosorbent assay showed the unique difference in the specificity between the two similar antibodies: mAb14A2 recognized several quercetin-3-glycosides including Q3G and rutin but mAb11G6 was highly specific to the Q3G structure. The macrophage-derived foam cells in human atherosclerotic lesions were significantly stained with mAb14A2 but scarcely with mAb11G6. These results showed that the anti-flavonoid glycoside antibodies are useful tools for evaluating their localization in tissues and that the specificities strongly depend on the immunogen design for synthesizing the hapten-protein conjugates.

Macrophage as a target of quercetin glucuronides in human atherosclerotic arteries: implication in the anti-atherosclerotic mechanism of dietary flavonoids.

Epidemiological studies suggest that the consumption of flavonoid-rich diets decreases the risk of cardiovascular diseases. However, the target sites of flavonoids underlying the protective mechanism in vivo are not known. Quercetin represents antioxidative/anti-inflammatory flavonoids widely distributed in the human diet. In this study, we raised a novel monoclonal antibody 14A2 targeting the quercetin-3-glucuronide (Q3GA), a major antioxidative quercetin metabolite in human plasma, and found that the activated macrophage might be a potential target of dietary flavonoids in the aorta. Immunohistochemical studies with monoclonal antibody 14A2 demonstrated that the positive staining specifically accumulates in human atherosclerotic lesions, but not in the normal aorta, and that the intense staining was primarily associated with the macrophage-derived foam cells. In vitro experiments with murine macrophage cell lines showed that the Q3GA was significantly taken up and deconjugated into the much more active aglycone, a part of which was further converted to the methylated form, in the activated macrophages. In addition, the mRNA expression of the class A scavenger receptor and CD36, which play an important role for the formation of foam cells, was suppressed by the treatment of Q3GA. These results suggest that injured/inflamed arteries with activated macrophages are the potential targets of the metabolites of dietary quercetin. Our data provide a new insight into the bioavailability of dietary flavonoids and the mechanism for the prevention of cardiovascular diseases.

Antidepressant effect of extracts from Ginkgo biloba leaves in behavioral models.

Extracts of Ginkgo biloba (EGB) are a complex product prepared from green leaves of the Ginkgo biloba tree. In the present study, the antidepressant effect of EGB was examined using two behavioral models, the forced swimming test (FST) in rats and tail suspension test (TST) in mice. EGB significantly reduced immobility time in the FST at a dosage of 10 and 50 mg/kg body weight after repeated oral treatment for 14 d, although no change of motor dysfunction was observed with the same dosage in the open field test. These results indicate that EGB might possess an antidepressant activity. In addition, EGB markedly shortened immobility time in the TST after acute inter-peritoneal treatment at a dosage of 50 and 100 mg/kg body weight. The present study clearly demonstrated that EGB exerts an antidepressant effect in these two behavioral models.

Effects of forced swimming stress on rat brain function.

Chronic stress has been reported to be an essential factor for depression. In this study, the effect of forced swimming stress on neurotransmitters and cellular signaling pathway contributing to brain functions was investigated using the forced swimming test (FST) in order to understanding of mechanisms to regulate stress signals in brain. Antidepressant drug, imipramine, significantly reduced the immobility time of male rats in the FST by 85% at a dose of 15 mg/kg for 2 weeks. This result indicated that the swimming stress caused a depressed state in the rats without administration of imipramine. Swimming stress significantly lowered the serotonergic ratio and also markedly enhanced the phosphorylation of ERK1/2 in the hypothalamus region compared to the rats without FST. These phenomena may be included in key mechanisms of the development of depression.