• Parasites, Hosts and Diseases
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• v.45 no.4
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• pp.295-299
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• 2007

The purpose of this study was to investigate whether sporulated Neospora caninum oocysts, which had been stored for 46 mo in a 2% sulfuric acid solution at $4^{\circ}C$, remain morphologically viable and infective to gerbils (Meriones unguiculatus). Six gerbils were orally inoculated with doses of 400 or 1,200 oocysts. Two mo after inoculation, the animals did not show any clinical signs, had no histological lesions, and were seronegative for N. caninum at 1:50 in an immunofluorescent antibody test. PCR using the brain from each gerbil did not reveal N. caninum specific DNA. We conclude that oocysts preserved for 46 mo are not infective, despite being morphologically intact.

• Korean Journal of Veterinary Research
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• v.46 no.4
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• pp.327-335
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• 2006

A stable and reliable Helicobacter pylori (H. pylori) infection animal model would be necessary for evaluating vaccine efficacy and helpful for understanding the pathological mechanism of the organism. The aim of the present study is to investigate the effect of ethanol treatment prior to H. pylori inoculation on associated gastric mucosal injury and to establish ethanol-pretreating animal model to study H. pylori infection. Male Mongolian gerbils were used for the study. H. pylori was orally inoculated after 12 h fasting. 3 h prior to H. pylori inoculation, a group of gerbils was orally treated with absolute ethanol, 60% and 40% ethanol respectively. Another group of animals was treated either with H. pylori culture media alone or with different concentrations of ethanol plus culture media. Gerbils were killed 4 or 8 weeks after H. pylori inoculation. The colonization of H. pylori was confirmed by both histological examination and rapid urease test. Mucosal damage was evaluated grossly and histologically according to the criteria. The colonization of H. pylori and pathological changes in gastric mucosa of the animals were also observed. Although no significant change to the gastric mucose was observed in the animals treated either with H. pylori culture media alone or with different concentrations of ethanol plus culture media, persistent H. pylori infection was seen in the mucosa and mucosal leucocyte infiltration and severe epithelial damage was observed in the Helicobacter and ethanol + Helicobacter groups after 4 weeks. The gross and histological scores were higher in the ethanol + Helicobacter than in the Helicobacter alone group. As the results, ethanol-pretreatment with 60% concentration induced severe pathogenic changes by H. pylori infection in 5 weeks-old Mongolian gerbils. These results suggested that ethanol-pretreatment before H. pylori inoculation could increase the severity of gastric mucosal inflammation and enhance the colonization of H. pylori. The established ethanol-pretreating animal model would contribute to screen new drugs against H. pylori and be used as an useful tool for various animal experiments with H. pylori strains.

• The Korean Journal of Pharmacology
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• v.30 no.3
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• pp.273-289
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• 1994

Reversible brain ischemia was produced by occluding both common carotid arteries for 5 min, and the effects of aminoguanidine (AG), $DL-{\alpha}-difluoromethylornithine$ (DFMO), MK-801, and nimodipine (NM) on the ischemia induced changes of the polyamine, glutamate and acetylcholine levels in the hippocampus CA1 subfield and the specific $[^3H]\;MK-801$ binding to the hippocampus synaptosomal membranes were studied with a histological reference of the cresyl violet stained hippocampus. The basal putrescine level $(PT:\;74.4{\pm}8.8\;nM)$ showed a rapid increase (up to 1.7 fold) for 5 min of ischemia, remained significantly increased for 6 h, and then resumed the further increase to amount gradually up to about 3 fold 96 h after recirculation. However, the level of spermidine was little changed, and the spermine level showed a transient increase during ischemia followed by a sustained decrease to about 40% of the preischemic level after recirculation. The increase of PT level induced by brain ischemia was enhanced with AG or MK-801, but it was reduced by DFMO or NM. The basal glutamate level $(GT:\;0.90{\pm}0.l4\;{\mu}M)$ rapidly increased to a peak level of $8.19{\pm}1.14\;{\mu}M$ within 5 min after onset of the ischemia and then decreased to the preischemic level in about 25 min after recirculation. And NM reduced the ischemia induced increase of GT level by about 25%, but AG, DFMO and MK-801 did not affect the GT increase. The basal acetylcholine level $(ACh:\;118.0{\pm}10.5\;{\mu}M)$ did little change during/after brain ischemia and was little affected by AG or NM. But DFMO and MK-801, respectively, produced the moderate decrease of ACh level. The specific $[^3H]\;MK-801$ binding to the hippocampus synaptosomal membrane was little affected by brain ischemia for 5 min. The control value (78.9 fmole/mg protein) was moderately decreased by AG and MK-801, respectively but was little changed by DFMO or NM. The microscopic findings of the brains extirpated on day 7 after ischemia showed severe neuronal damage of the hippocampus, particularly CA1 subfield. NM and AG moderately attenuated the delayed neuronal damage, and DFMO, on the contrary, aggravated the ischemia induced damage. However, MK-801 did not protect the hippocampus from ischemic damage. These results suggest that unlike to the mode of anti-ischemic action of NM, AG might protect the hippocampus from ischemic injury as being negatively regulatory on the N-methyl-D-aspartate (NMDA) receptor function in the hippocampus.

• Korean Journal of Veterinary Research
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• v.41 no.4
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• pp.467-475
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• 2001

Cardiac arrest, hypoxia, shock or seizure has been known to induce cerebral ischemia. This study was designed to investigate the effect of ischemia on hippocampal pyramidal layer induced by transient bilateral occlusion of the common carotid arteries. Mature Mongolian gerbils were sacrificed at days 2, 4, and 7 after carotid occlusion for 10 minutes. Sham-operated gerbils of control group were subjected to the same protocol except for carotid occlusion. During operation for ischemia, body temperature was maintained $37{\pm}0.5^{\circ}C$ in all gerbils. Paraffin-embedded brain tissue blocks were cut into coronal slices and stained with H-E stain or immunostain by TUNEL method. Neurons with the oval and prominent nucleus and without the eosinophilic cytoplasm in the subfield of hippocamapal pyramidal layer were calculated as to be viable neurons. Their chromatins were condensed or clumped. Their nuclei appeared multiangular or irregularly shrinked. The width of the pyramidal layer was reduced due to the loss of nuclei. At day 2 after reperfusion, some neurons in the CA1 subfield were slightly eosinophilic. But most neurons in the CA2 subfield were strongly eosinophilic. At day 4 day, most neurons in the CA1 subfield were severely damaged and at day 7 day, only a few survived neurons were observed. Survived neurons per longitudinal 1mm sector in the CA1, CA2, CA3, and CA4 subfields of pyramidal layer were investigated. At day 2, the mean numbers of pyramidal neurons in CA1, CA2, CA3, and CA4 subfiedls were 104.5/mm (54.3%), 51.0/mm (33.8%), 105.5/mm (85.6%), and 124.3/mm (93.5%) compared to the nonischemic control group, respectively. At day 4, the mean numbers of pyramidal neurons in CA1, CA2, CA3, and CA4 subfields were 3.2/mm (1.7%), 51.5/mm(34.2%), 95.3/mm (77.4%), and 112.5/mm (84.6%), respectively. At day 7, the mean numbers of pyramidal neurons in CA1, CA2, CA3, and CA4 subfiedls were 0.8/mm (0.4%), 5.7/mm(3.8%), 9.8/mm (8.0%), and 5.0/mm (3.7%), respectively. The mean numbers of apoptotic positive neurons in the CA1 subfield at day 2, 4, and 7 after reperfusion were 67.8/mm, 153.2/mm and 123.7/mm, respectively. These results suggest that the transient cerebral ischemia cause severe damages in most neurons at day 7 and that the prosminent apoptotic positive neurons in hippocampal pyramidal layer are the delayed neuronal death induced by ischemia.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.4
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• pp.161-167
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• 2015

These commensal intestinal bacteria can enhance the immune system and aid in nutrient absorption but can also act as opportunistic pathogens. Among these intestinal bacteria, the anaerobic Bacteroides fragilis are divided into enterotoxigenic B. fragilis (ETBF) which secrete the B. fragilis toxin (BFT) and non-enterotoxigenic B. fragilis (NTBF) which do not secrete BFT. ETBF can cause diarrhea and colitis in both humans and livestock but can also be found in asymptomatic individuals. ETBF is predominantly found in patients with inflammatory diarrheal diseases and traveller's diarrhea. Several clinical studies have also reported an increased prevalence of ETBF in human patients with inflammatory bowel disease (IBD), colitis and colorectal cancer. In small animal models (C57BL/6 wild-type mice, germ-free mice, multiple intestinal neoplasia (Min) mice, rabbits and Mongolian gerbils), ETBF have been found to initiate and/or aggravate IBD, colitis and colorectal cancer. BFT induces E-cadherin cleavage in intestinal epithelial cells resulting in loss of epithelial cell integrity. Subsequent activation of the ${\beta}$-catenin pathway leads to increased cellular proliferation. In addition, ETBF causes acute and chronic colitis in wild-type mice as well as enhances tumorigenesis in Min mice via activation of the Stat3/Th17 pathway. Currently, ETBF can be detected using a BFT toxin bioassay and by PCR. Advances in molecular biological techniques such as real-time PCR have allowed both researchers as well as clinicians to rapidly detect ETBF in clinical samples. The emergence of more sensitive techniques will likely advance molecular insight into the role of ETBF in colitis and cancer.

• Journal of Korean Medicine Rehabilitation
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• v.18 no.4
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• pp.1-11
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• 2008

Objectives : Cerebral ischemia resulting from transient or permanent occlusion of cerebral arteries leads to neuronal cell death and eventually causes neurological impairments. Scrophulariae radix is the roots of Scrophularia buergeria. In the present study, we investigated the effects of the aqueous extract of Scrophulariae radix on apoptotic cell death in the hippocampal dentate gyrus following transient global ischemia in gerbils. Methods : For this study, step-down avoidance task, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay, and immunohistochemistry for caspase-3 were performed. Results : The present results showed that apoptotic cell death in the hippocampal dentate gyrus was significantly increased following transient global ischemia in gerbils. Treatment with the aqueous extract of Scrophulariae radix suppressed the ischemia-induced apoptosis in the dentate gyrus and thus facilitated the recovery of short-term memory impairment induced by ischemic cerebral injury. Conclusions : Here in this study, we have shown that Scrophulariae radix has a positive effect on-and possesses protective qualities against ischemia-induced apoptotic neuronal cell death, and it can be used for the treatment of ischemic brain diseases.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.3
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• pp.594-601
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• 2002

The current study was carried out to evaluate neuroprotective effects of Citri Pericarpium after transient global ischemia in gerbils. Male Mongolian gerbils weighing 60-80g were anesthetized with 2% isoflurane mixed with 30% oxygen and 70 % nitrogen. Bilateral common carotid arteries were occluded for 5 minute with microaneurysm dips. On 3 or 7 days after ischemic surgery, the gerbils were sacrificed. The brain were removed, embedded in paraffin and sectioned at 8㎛-thickness. Gerbils that received ischemic insult for 5 min showed extensive neuronal damage in the hippocampal CA1 region, and the number of viable neuronal cell was 51.0±2.5/mm, 32.2% of normal group at 7 days after ischemic surgery. In animals that underwent the extract of Citri Pericarpium treatment, the number of viable neuronal cell were significantly better preserved at 110.58±3.58/mm, 72.0% of normal group than those of ischemic group (P<0.01). In the immunohistochemistry of Bax and Bcl-2, the Citri Pericarpium treated group down-regulated the expression of Bax protein at 72hr after transient global ischemia. In contrast, Bcl-2 protein level was not changed. The appearance in TUNEL assay is similar to the pattern of Bax protein. The water extract of Citri Pericarpium significantly reduced the number of TUNEL-positive CA1 pyramidal neurons at 72hr. The results suggest that Citri Pericarpium has potential neuroprotective effects in the transient global ischemia and the increase in the ratio of Bcl-2 to Bax may contribute to the anti-apoptotic effect of Citri Pericarpium.

• Journal of Ginseng Research
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• v.43 no.2
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• pp.326-334
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• 2019

Background: The objective of our study was to analyze the neuroprotective effects of ginsenoside derivatives Rb1, Rb2, Rc, Rd, Rg1, and Rg3 against glutamate-mediated neurotoxicity in HT22 hippocampal mouse neuron cells. Methods: The neuroprotective effect of ginsenosides were evaluated by measuring cell viability. Protein expressions of mitogen-activated protein kinase (MAPK), Bcl2, Bax, and apoptosis-inducing factor (AIF) were determined by Western blot analysis. The occurrence of apoptotic and death cells was determined by flow cytometry. Cellular level of $Ca^{2+}$ and reactive oxygen species (ROS) levels were evaluated by image analysis using the fluorescent probes Fluor-3 and 2',7'-dichlorodihydrofluorescein diacetate, respectively. In vivo efficacy of neuroprotection was evaluated using the Mongolian gerbil of ischemic brain injury model. Result: Reduction of cell viability by glutamate (5 mM) was significantly suppressed by treatment with ginsenoside Rb2. Phosphorylation of MAPKs, Bax, and nuclear AIF was gradually increased by treatment with 5 mM of glutamate and decreased by co-treatment with Rb2. The occurrence of apoptotic cells was decreased by treatment with Rb2 ($25.7{\mu}M$). Cellular $Ca^{2+}$ and ROS levels were decreased in the presence of Rb2, and in vivo data indicated that Rb2 treatment (10 mg/kg) significantly diminished the number of degenerated neurons. Conclusion: Our results suggest that Rb2 possesses neuroprotective properties that suppress glutamate-induced neurotoxicity. The molecular mechanism of Rb2 is by suppressing the MAPKs activity and AIF translocation.

• The Korean Journal of Pharmacology
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• v.32 no.3
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• pp.335-345
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• 1996

A critical role of oxygen-derived free radicals has been implicated in ischemia/reperfusion (I/R)-induced brain damage. In this study, we have produced experimental I/R to the brains of Mongolian gerbil (Meriones unguiculatus) by a transient occlusion and release of the common carotid arteries. We have attempted to determine whether the oxidative stress is generated upon I/R and whether this oxidative stress is linked to the cell damage. Since hippocampus has been suggested as one of the most vulnerable regions of the brain to the oxidative stress, we analyzed samples from hippocampus in comparison with those from cortex. In addition, we have examined the expression of heat shock protein 70kD species (HSP70) in these regions in order to evaluate a possible role of this protein in I/R-induced brain damage. To determine whether the oxidative stress is produced upon I/R, we measured the glutathione oxidation, GSSG/ (GSH + 2xGSSG), as an index of oxidative stress. We found an increase of the glutathione oxidation primarily in hippocampus upon I/R. To determine whether this oxidative stress is linked to the cell damage, we measured the degree of lipid peroxidation upon I/R. We found an increase of lipid peroxidation in both regions. However, the magnitude of increases was greater in hippocampus than in cortex. In addition, we found that changes in both the magnitude and the temporal patterns of glutathione oxidation closely correlated with those of lipid peroxidation. Our study provides biochemical evidences that the oxidative stress is generated upon I/R and this oxidative stress is linked to the oxidative cell damage. Our study also provides evidences that the degree of oxidative stress as well as oxidative cell damage is greater in hippocampus than in cortex. We could not find difference in the basal level of HSP70 expression between hippocampus and cortex, indicating that the intrinsic vulnerability of hippocampus cannot be explained by the lower level of HSP70 expression. We did find, however, that the induction of HSP70 expression upon I/R was impaired in the hippocampus. This impairment appeared to be at the transcriptional level. These results suggest that the measurement of HSP70 induction may be employed as a useful predictor of differential cellular susceptibilities to the I/R-induced brain damage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.5
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• pp.605-611
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• 2012

Sea cucumber, $Stichopus$ $japonicus$, is used not only as an outstanding tonic food but also as a traditional medicine for the treatment of asthma, hypertension, rheumatism, anemia, and sinus congestion. The purpose of this study was to examine sea cucumber as an anti-gastritis and anti-gastric ulcer in HCl-ethanol-induced gastric and $H.$ $pylori$-infected animal models. Thirty 7-week-old SD rats and Mongolian gerbils were divided into normal (Nor, n=6), control (Con, 60% HCl-ethanol+water, n=6), groupI (DSCI, 60% HCl-ethanol+sea cucumber 30 mg/kg, n=6), groupII (DSCII, 60% HCl-ethanol+sea cucumber 100 mg/kg, n=6), and group III (DSCIII, 60% HCl-ethanol+sea cucumber 300 mg/kg, n=6). Sea cucumber significantly suppressed gastric lesions and ulcers in the 60% HCl-ethanol-induced gastric model. Especially, 100 mg/kg of sea cucumber showed significantly inhibitory effects. In histopathological analysis of the $H.$ $pylori$ model, we found that sea cucumber augmented the eradication rates of $H.$ $pylori$ and attenuated gastric ulcer formation. Our results suggest that sea cucumber has inhibitory effects on gastritis and gastric ulcers. In addition, sea cucumber can be applied for the treatment of $H.$ $pylori$.