Inhibition of Amyloid-β (Aβ)-Induced Cognitive Impairment and Neuroinflammation in CHI3L1 Knockout Mice through Downregulation of ERK-PTX3 Pathway

Several clinical studies reported that the elevated expression of Chitinase-3-like 1 (CHI3L1) was observed in patients suffering from a wide range of diseases: cancer, metabolic, and neurological diseases. However, the role of CHI3L1 in AD is still unclear. Our previous study demonstrated that 2-({3-[2-(1-Cyclohexen-1-yl)ethyl]-6,7-dimethoxy-4-oxo-3,4-dihydro-2-quinazolinyl}culfanyl)-N-(4-ethylphenyl)butanamide, a CHI3L1 inhibiting compound, alleviates memory and cognitive impairment and inhibits neuroinflammation in AD mouse models. In this study, we studied the detailed correlation of CHI3L1 and AD using serum from AD patients and using CHI3L1 knockout (KO) mice with Aβ infusion (300 pmol/day, 14 days). Serum levels of CHI3L1 were significantly elevated in patients with AD compared to normal subjects, and receiver operating characteristic (ROC) analysis data based on serum analysis suggested that CHI3L1 could be a significant diagnostic reference for AD. To reveal the role of CHI3L1 in AD, we investigated the CHI3L1 deficiency effect on memory impairment in Aβ-infused mice and microglial BV-2 cells. In CHI3L1 KO mice, Aβ infusion resulted in lower levels of memory dysfunction and neuroinflammation compared to that of WT mice. CHI3L1 deficiency selectively inhibited phosphorylation of ERK and IκB as well as inhibition of neuroinflammation-related factors in vivo and in vitro. On the other hand, treatment with recombinant CHI3L1 increased neuroinflammation-related factors and promoted phosphorylation of IκB except for ERK in vitro. Web-based gene network analysis and our results showed that CHI3L1 is closely correlated with PTX3. Moreover, in AD patients, we found that serum levels of PTX3 were correlated with serum levels of CHI3L1 by Spearman correlation analysis. These results suggest that CHI3L1 deficiency could inhibit AD development by blocking the ERK-dependent PTX3 pathway.

Establishment of high-performance liquid chromatography-photodiode array method for 43 weight loss agents and effect of basic environment on bisacodyl degradation

RATIONALE

The demand for weight loss products is increasing as slimness emerges as the new aesthetic standard and people's desire to achieve it increases. In addition, the distribution and sale of products containing illegal ingredients, pharmaceuticals, and chemicals for which safety is not guaranteed and that cannot be used as foods or dietary supplements are increasing. Thus, the development of an analytical method that could monitor these illegal products is required.

METHODS

A high-performance liquid chromatography-photodiode array method capable of rapid and reliable qualitative and quantitative analyses of 43 weight loss agents was established and validated.

RESULTS

The process involved dividing analytes into three groups for rapid analysis; when bisacodyl was mixed with chlorocyclopentylsibutramine, it decomposed into its metabolites: monoacetyl bisacodyl and bis-(p-hydroxypheny)-pyridyl-2-methane. This decomposition was due to NaOH that was used to prepare the chlorocyclopentylsibutramine standard solution. Bisacodyl did not degrade when mixed with neutralized chlorocyclopentylsibutramine, whereas when NaOH was added, it rapidly degraded. We identified the bisacodyl degradation products using liquid chromatography-quadrupole-Orbitrap/mass spectrometry. MS2 spectra with proposed structures of fragment peaks were also obtained.

CONCLUSIONS

The developed method could be used to regulate slimming products that threaten public health, and knowledge of bisacodyl degradation will be used as the basis for developing an analytic method.

Presenilin-2 knock-In mice show severe depressive behavior via DVL3 downregulation

INTRODUCTION

Alzheimer's disease (AD) is the most common form of dementia. Depression is one of the most critical psychiatric complications of AD, and 20%-30% of patients with AD experience symptoms of depression. Phospho-glycogen synthase kinase-3 beta (GSK3β) is known to be associated with AD and depression. Furthermore, the role of disheveled (DVL) is known to regulate GSK3β. Moreover, presenilin-2 (PS2) and DVL have cross-talk with each other. Also, it is widely hypothesized that stress leads to hypersecretion of cortisol and is thus associated with depression. Dickkopf WNT signaling pathway inhibitor-1 (DKK-1) is a crucial factor regulating depression and both amyloid beta (Aβ) and phosphorylation of tau are widely known as a biomarker of AD.

METHODS

To investigate the relationship between AD and depression, and possible pathways connecting the two diseases, we examined memory function and depression-related behavior test results in PS2 knock-in AD mice (PS2 MT). Next, we confirmed that there are relationships between DVL, depression, and cognitive disease through the comparative toxicogenomics database (https://ctdbase.org) and STRING (https://string-db.org) database.

RESULTS

PS2 knock-in mice showed much more severe memory impairment and depression than PS2 wild-type mice (PS2 WT). In AD-related behavioral experiments, PS2 MT mice showed more memory dysfunction compared with PS2 WT group mice. Moreover, Aβ and phosphorylation of tau showed higher expression in PS2 MT mice than in PS2 WT mice. Depression-related behavioral tests showed that PS2 MT mice exhibited more depressive behaviors than PS2 WT mice. Furthermore, both higher cortisol levels and higher expression of DKK-1 were found in PS2 MT mice relative to PS2 WT mice. The results indicated that there is a relationship between DVL and the release of AD-related mediators and expression of the depression-related glucocorticoid receptor and DKK-1. In the PS2 knock-in group, DVL was significantly decreased compared with the PS2 WT group.

CONCLUSION

Depression increases the risk of developing AD and other forms of dementia. Recent evidence indicates that depression symptoms could trigger changes in memory and thinking over time. However, it is recognized that there are no drugs to facilitate a full recovery for both AD and depression. However, our results suggest that AD and depression could be associated, and DVL could be a significant target for the association between AD and depression.

Liquid chromatography-quadrupole orbitrap and liquid chromatography-tandem mass spectrometry system for rapid identification and quantitation of thirty nonsteroidal anti-inflammatory drugs and acetaminophen in illegal products

RATIONALE

As the public interest in healthcare increases, illegal dietary supplements, foods, and drugs containing unauthorized pharmaceutical ingredients, including nonsteroidal anti-inflammatory drugs (NSAIDs) and acetaminophen, have been identified. Excessive and unintentional consumption is toxic to the gastrointestinal tract, kidneys, and liver; therefore, these pharmaceuticals must be monitored using analytical methods.

METHODS

A rapid and reliable analysis system involving liquid chromatography-quadrupole orbitrap mass spectrometry (LC-Q-Orbitrap/MS) and liquid chromatography-tandem mass spectrometry (LC/MS/MS) was established and validated to identify and quantify 30 NSAIDs and acetaminophen. In addition, we obtained the MS² spectrum for each component with the proposed structure of the fragment ions.

RESULTS

The analytical method was applied to 505 samples of illicitly distributed dietary supplements, foods, and pharmaceuticals. Non-steroidal analgesics were detected in 126 samples. Carbamazepine (42.9%) and diclofenac (30.2%) were the most detected components in the samples; other pharmaceutical adulterants were also detected in some cases. Additionally, we present the identification of an unknown component, dexamethasone (799 μg/g), using LC-Q-Orbitrap/MS in a sample containing the unknown component with meloxicam (15.4 mg/g).

CONCLUSIONS

The developed analysis system, consisting of qualitative analysis using LC-Q-Orbitrap/MS and quantitative analysis using LC/MS/MS, can rapidly and accurately identify and quantify NSAIDs and acetaminophen while also identifying non-analytical components.

Simultaneous quantitation of 17 female sex hormones in illegal products by validated LC-high resolution MS and LC-tandem MS methods

The consumption of food and drugs adulterated with female sex hormones can have an extremely adverse effect on human health. Therefore, developing appropriate monitoring methods for the identification of various exogenous female sex hormones is crucial for minimizing and eliminating the related health risks. Herein, 17 female hormones categorized into two groups, estrogen and progestin, were analyzed using reversed phase LC coupled to Orbitrap or triple quadrupole MS. The fragmentation patterns for all compounds were discovered, and fragmented structures were also derived from them through LC-high resolution MS followed by qualitative sample analysis. In addition, quantitative analysis of 67 samples of illicit drugs and dietary supplements was performed using the validated LC-tandem MS method. Female hormone components were detected in two samples of an unauthorized injectable solution and a tablet-type drug. Medroxyprogesterone was detected in the samples in the range of 96.4-206 ng/g. Notably, eight components similar in structure to steroids were simultaneously detected as male sex hormones by confirming their fragmentation ion patterns using LC-high resolution MS. The developed methods thus offer a dependable, and practically applicable approach for the screening and detection of exogenous female sex hormones in real food and drug samples to ensure public health. This article is protected by copyright. All rights reserved.

Application of LC-MS/MS and UHPLC-Q-Orbitrap methods for determining 54 steroids in illegal dietary supplements and other sample types

RATIONALE

With the development of the Internet and social network services, the public access to or use of illegal products has been increased via on/offline black markets. Steroids refer to the compounds yielding strong treatment effects on some diseases or muscle building, and are classified as the pharmaceutical compounds that are prohibited for personal use without a prescription. The prohibition is made for their potential risk to cause serious adverse effects along with their efficacies.

METHODS

To monitor the distribution of illicit products containing steroids, a simple and reliable analytical method was established and validated, allowing rapid and simultaneous determination of 54 steroids in them. During the screening, LC-Q-Orbitrap/MS was performed first followed by quantitative analysis using LC-MS/MS. For the accurate and reliable analysis, the samples were extracted using QuEChERS to reduce the matrix effect.

RESULTS

After the screening of 617 illegal samples advertised as being effective in alleviating various diseases or improving athletic performance with the established LC-Q-Orbitrap/MS method, the validated LC-MS/MS method was used to perform the quantitative analysis of the detected steroids. Of these, 142 samples were adulterated with steroids, and several samples with two or more steroids were detected. Due to the lack of previous studies on the toxicity of these illicit products, the side effects of consuming them are unpredictable and could be harmful.

CONCLUSIONS

The development of LC-Q-Orbitrap/MS method accompanied by LC-MS/MS could be successfully applied to the inspection of illegal steroid products for public health, enabling the rapid and accurate detection of analytes and incorporation of non-analyte components.

Application of LC-high resolution MS and LC-tandem MS methods to 45 weight loss compounds in health functional food, food and illegal drug

In order to effectively and quickly monitor such illegal food and drugs, simultaneous screening and quantitative analysis for multiple compounds are needed. In this study, we established a method of identifying fragmentation ions of 45 compounds for weight loss using liquid chromatography and high resolution MS, and developed a quantitation method through liquid chromatography and tandem MS. 656 samples selected as health functional food, food, and illegal drug were applied. The detection rate of banned weight loss compounds in health functional food, food, and illegal drug was showed as 19.2%, 27.3%, 40.7%, respectively. Among them, sibutramine, sennoside A and B, ephedrine were most frequently detected in 237 samples that contained weight loss compounds. The detection range about sibutramine was 0.03-159.3mg/g, sennoside was 0.1-97.6mg/g, and ephedrine was 0.1-587.7mg/g in the detected 237 samples. In addition, the unknown compounds not included in our simultaneous analysis method in some samples were identified as furosemide and chlorpheniramine. This article is protected by copyright. All rights reserved.

Development of a method for simultaneous screening of four natural-derived steroids and their analogues used as dietary supplements via liquid chromatography-quadrupole-time of flight mass spectrometry and liquid chromatography-tandem mass spectrometry

Natural-derived steroids and their analogues are present in various plants and insects. To minimize the chance of missing a positive doping test and avoiding potentially serious health problems, adequate screening methods are necessary for the detection of a wide range of natural-derived steroids and their analogues in dietary supplements. In this study, an accurate and simple liquid-chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to determine and quantify the natural-derived steroids and their analogues according to the International Conference on Harmonization of technical Requirements for Registration of Pharmaceuticals for Human Use guidelines. The validation results indicating excellent extraction efficiency and low matrix effects show that the LC-MS/MS method is reliable for the detection of natural-derived steroids and their analogues. In addition, we established the ion fragmentation of turkesterone and ion fragmentation of four natural-derived steroids and their analogues. The validated method was applied to 60 dietary supplements purchased online and in person from international vendors in 2020. Ecdysterone and 5α-hydroxylaxogenin were detected respectively in 3 and 14 of 60 dietary supplements. Especially, a high amount of 5α-hydroxylaxogenin, an FDA-unapproved ingredient, was detected in two of dietary supplements (44.4 and 32.3 mg/g). This component should be controlled since it may cause unexpected side effects if administered excessively. Thus, this method will be helpful for the continuous control and supervision of unlicensed dietary supplements containing natural-derived steroids and their analogues.

G721-0282 Exerts Anxiolytic-Like Effects on Chronic Unpredictable Mild Stress in Mice Through Inhibition of Chitinase-3-Like 1-Mediated Neuroinflammation

Chronic stress is thought to be a major contributor to the onset of mental disorders such as anxiety disorders. Several studies have demonstrated a correlation between anxiety state and neuroinflammation, but the detailed mechanism is unclear. Chitinase-3-like 1 (CHI3L1) is expressed in several chronic inflammatorily damaged tissues and is well known to play a major role in mediating inflammatory responses. In the present study, we investigated the anxiolytic-like effect of N-Allyl-2-[(6-butyl-1,3-dimethyl-2,4-dioxo-1,2,3,4-tetrahydropyrido[2,3-d]pyrimidin-5-yl)sulfanyl]acetamide (G721-0282), an inhibitor of CHI3L1, on mice treated with chronic unpredictable mild stress (CUMS), as well as the mechanism of its action. We examined the anxiolytic-like effect of G721-0282 by conducting several behavioral tests with oral administration of G721-0282 to CUMS-treated BALB/c male mice. We found that administration of G721-0282 relieves CUMS-induced anxiety. Anxiolytic-like effects of G721-0282 have been shown to be associated with decreased expressions of CUMS-induced inflammatory proteins and cytokines in the hippocampus. The CUMS-elevated levels of CHI3L1 and IGFBP3 were inhibited by treatment with G721-0282 in vivo and in vitro. However, CHI3L1 deficiency abolished the anti-inflammatory effects of G721-0282 in microglial BV-2 cells. These results suggest that G721-0282 could lower CUMS-induced anxiety like behaviors by regulating IGFBP3-mediated neuroinflammation via inhibition of CHI3L1.

Botulinum Toxin A Ameliorates Neuroinflammation in the MPTP and 6-OHDA-Induced Parkinson's Disease Models

Recently, increasing evidence suggests that neuroinflammation may be a critical factor in the development of Parkinson's disease (PD) in addition to the ratio of acetylcholine/dopamine because dopaminergic neurons are particularly vulnerable to inflammatory attack. In this study, we investigated whether botulinum neurotoxin A (BoNT-A) was effective for the treatment of PD through its anti-neuroinflammatory effects and the modulation of acetylcholine and dopamine release. We found that BoNT-A ameliorated MPTP and 6-OHDA-induced PD progression, reduced acetylcholine release, levels of IL-1β, IL-6 and TNF-α as well as GFAP expression, but enhanced dopamine release and tyrosine hydroxylase expression. These results indicated that BoNT-A had beneficial effects on MPTP or 6-OHDA-induced PD-like behavior impairments via its anti-neuroinflammation properties, recovering dopamine, and reducing acetylcholine release.

Improved Anti-Inflammatory Effects of Liposomal Astaxanthin on a Phthalic Anhydride-Induced Atopic Dermatitis Model

Previously, we found that astaxanthin (AST) elicited an anti-inflammatory response in an experimental atopic dermatitis (AD) model. However, the use of AST was limited because of low bioavailability and solubility. We hypothesized that liposome formulation of AST could improve this. In this study, we compared the anti-inflammatory and anti-dermatotic effects of liposomal AST (L-AST) and free AST. We evaluated the effect of L-AST on a phthalic anhydride (PA)-induced animal model of AD by analyzing morphological and histopathological changes. We measured the mRNA levels of AD-related cytokines in skin tissue and immunoglobulin E concentrations in the serum. Oxidative stress and transcriptional activities of signal transducer and activator of transcription 3 (STAT3) and nuclear factor (NF)-κB were analyzed via western blotting and enzyme-linked immunosorbent assay. PA-induced dermatitis severity, epidermal thickening, and infiltration of mast cells in skin tissues were ameliorated by L-AST treatment. L-AST suppressed AD-related inflammatory mediators and the inflammation markers, inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 in PA-induced skin conditions. Oxidative stress and expression of antioxidant proteins, glutathione peroxidase-1 (GPx-1) and heme oxygenase-1 (HO-1), were recovered by L-AST treatment in skin tissues from PA-induced mice. L-AST treatment reduced transcriptional activity of STAT3 and NF-κB in PA-induced skin tissues. Our results indicate that L-AST could be more effective than free AST for AD therapy.

K284-6111 alleviates memory impairment and neuroinflammation in Tg2576 mice by inhibition of Chitinase-3-like 1 regulating ERK-dependent PTX3 pathway

Background

Alzheimer’s disease (AD) is one of the most prevalent neurodegenerative disorders characterized by gradual memory loss and neuropsychiatric symptoms. We have previously demonstrated that the 2-({3-[2-(1-cyclohexene-1-yl)ethyl]-6,7-dimethoxy-4-oxo-3,4-dihydro-2-quinazolinyl}sulfanyl)-N-(4-ethylphenyl)butanamide (K284-6111), the inhibitor of CHI3L1, has the inhibitory effect on memory impairment in Αβ infusion mouse model and on LPS-induced neuroinflammation in the murine BV-2 microglia and primary cultured astrocyte.

Methods

In the present study, we investigated the inhibitory effect of K284-6111 on memory dysfunction and neuroinflammation in Tg2576 transgenic mice, and a more detailed correlation of CHI3L1 and AD. To investigate the effects of K284-6111 on memory dysfunction, we administered K284-6111 (3 mg/kg, p.o.) daily for 4 weeks to Tg2576 mice, followed by behavioral tests of water maze test, probe test, and passive avoidance test.

Results

Administration of K284-6111 alleviated memory impairment in Tg2576 mice and had the effect of reducing the accumulation of Aβ and neuroinflammatory responses in the mouse brain. K284-6111 treatment also selectively inactivated ERK and NF-κB pathways, which were activated when CHI3L1 was overexpressed, in the mouse brain and in BV-2 cells. Web-based gene network analysis and our results of gene expression level in BV-2 cells showed that CHI3L1 is closely correlated with PTX3. Our result revealed that knockdown of PTX3 has an inhibitory effect on the production of inflammatory proteins and cytokines, and on the phosphorylation of ERK and IκBα.

Conclusion

These results suggest that K284-6111 could improve memory dysfunction by alleviating neuroinflammation through inhibiting CHI3L1 enhancing ERK-dependent PTX3 pathway.

Bee Venom Soluble Phospholipase A2 Exerts Neuroprotective Effects in a Lipopolysaccharide-Induced Mouse Model of Alzheimer's Disease via Inhibition of Nuclear Factor-Kappa B

Neuroinflammation is important in the pathogenesis and development of Alzheimer's disease (AD). In the AD brain, microglial activation and upregulation of pro-inflammatory mediators both induce amyloid beta (Aβ) accumulation. Regulatory T cells (Tregs) and nuclear factor-kappa B (NF-κB) signaling have been implicated in AD development through their effects on neuroinflammation and microglial activation. The bee venom soluble phospholipase A2 (bv-sPLA2) enzyme is known to exert anti-inflammatory and anti-immune effects. Here, we investigated the inhibitory effects of bv-sPLA2 on memory deficiency in a lipopolysaccharide (LPS)-induced mouse model of AD. We examined whether bv-sPLA2 (0.02, 0.2, and 2 mg/kg by i.p. injection three times for 1 week) could inhibit neuroinflammation and memory impairment in LPS-treated mice (250 μg/kg by i.p. injection daily for 1 week). We also assessed the effects of bv-sPLA2 administration (0.01, 0.1, and 1 μg/ml) on LPS (1 μg/ml)-treated microglial BV-2 cells. In the LPS-injected mouse brain, sPLA2 treatment rescued memory dysfunction and decreased Aβ levels, through the downregulation of amyloidogenic proteins, and decreased the expression of inflammatory proteins and pro-inflammatory cytokines. Moreover, the LPS-mediated increase in inflammatory protein expression was attenuated bv-sPLA2 treatment in BV-2 cells. Treatment with bv-sPLA2 also downregulated signaling by NF-κB, which is considered to be an important factor in the regulation of neuroinflammatory and amyloidogenic responses, both in vivo and in vitro. Additionally, co-treatment with NF-κB (5 μM) and bv-sPLA2 (0.1 μg/ml) exerted more marked anti-inflammatory effects, compared to bv-sPLA2 treatment alone. These results indicate that bv-sPLA2 inhibits LPS-induced neuroinflammation and amyloidogenesis via inhibition of NF-κB.

Bee venom phospholipase A2 ameliorates amyloidogenesis and neuroinflammation through inhibition of signal transducer and activator of transcription-3 pathway in Tg2576 mice

Background

Neuroinflammation and accumulation of β-amyloid (Aβ) play a significant role in the onset and progression of Alzheimer’s disease (AD). Our previous study demonstrated that signal transducer and activator of transcription-3 (STAT3) plays a major role in neuroinflammation and amyloidogenesis.

Methods

In the present study, we investigated the inhibitory effect of bee venom phospholipase A2 (bvPLA2) on memory deficiency in Tg2576 mice, which demonstrate genetic characteristics of AD and the mechanism of its action at the cellular and animal level. For in vivo study, we examined the effect of bvPLA2 on improving memory by conducting several behavioral tests with the administration of bvPLA2 (1 mg/kg) to Tg2576 mice. For in vitro study, we examined the effect of bvPLA2 on amyloidogenesis and neuroinflammation by treating bvPLA2 on LPS-activated BV2 cells.

Results

We found that bvPLA2 alleviated memory impairment in Tg2576 mice, as demonstrated in the behavioral tests assessing memory. In the bvPLA2-treated group, Aβ, amyloid precursor protein (APP), and β-secretase 1 (BACE1) levels and β-secretase activity were significantly decreased. Expression of pro-inflammatory cytokines and inflammation-related proteins decreased in the brain of bvPLA2-treated group, whereas anti-inflammatory cytokines increased. In addition, bvPLA2 reduced STAT3 phosphorylation in the brains of the bvPLA2-treated group. At the cellular level, bvPLA2 inhibits production of nitric oxide, pro-inflammatory cytokines, and inflammation-related proteins including p-STAT3. Additionally, bvPLA2 inhibits the production of Aβ in cultured BV-2 cells. Results from the docking experiment, pull-down assay, and the luciferase assay show that bvPLA2 directly binds STAT3 and, thus, regulates gene expression levels. Moreover, when the STAT3 inhibitor and bvPLA2 were administered together, the anti-amyloidogenic and anti-inflammatory effects were further enhanced than when they were administered alone.

Conclusion

These results suggest that bvPLA2 could restore memory by inhibiting the accumulation of Aβ and inflammatory responses via blockage of STAT3 activity.

Electronic supplementary material

The online version of this article (10.1186/s40035-019-0167-7) contains supplementary material, which is available to authorized users.

Evaluation of 2-[18F]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography in rat models with hepatocellular carcinoma with liver cirrhosis

Liver cirrhosis is a predominant risk factor for hepatocellular carcinoma (HCC). However, the exact mechanism of the progression from cirrhosis to cancer remains unclear. The uptake of 2-[(18)F]-fluoro-2-deoxy-D-glucose ((18)F-FDG) is widely used as a marker of increased glucose metabolism to monitor the progression of cancer with positron emission tomography (PET)/computed tomography (CT). Here we investigated the feasibility of using (18)F-FDG PET/CT in the diethylnitrosamine (DEN) mediated experimental hepatocellular carcinoma model. Rats received weekly intraperitoneal injections of DEN for 16 weeks for induction of HCC. We recorded starting from 0 days or 0 weeks after the last DEN injection. The weight and survival rate of rats were then measured. Also, an (18)F-FDG PET scan and serum analysis were performed at minus 2, 0, plus 2, and plus 4 weeks after the last DEN injection. The body weight of rats was maintained between 350 g and 370 g during 14 and 20 weeks, and the rats were euthanized at 35 days after the last DEN injection. The serum levels of alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphate (ALP) were significantly higher at zero weeks after the last DEN injection. The (18)F-FDG uptake for the quantitative evaluation of HCC was done by measuring the region of interest (ROI). At minus two weeks after the last DEN injection, the ROI of rats had significantly increased compared to the normal group, in a time-dependent manner. These results suggest that FDG uptake serves as a good screening test to evaluate the feasibility of DEN-induced HCC.

Prevalence, capsular type and antimicrobial susceptibility of Streptococcus suis isolated from slaughter pigs in Korea

This study was undertaken to determine the prevalence, capsular serotype, and antimicrobial susceptibility of Streptococcus suis isolated from slaughter pigs. Capsular serotype and antimicrobial susceptibility were determined by coagglutination test and agar dilution minimum inhibitory concentration, respectively. Streptococcus suis was isolated from 55 of the 406 palatine tonsillar samples tested (13.8%) and 14 of the 29 sampled herds (48.3%). Of the 55 isolates recovered from slaughter pigs, 26 (47.3%) were untypeable. Of the remaining 29 isolates, capsular serotypes 9 (9 isolates) and 16 (4 isolates) were the most common, followed by capsular serotypes 4 (3 isolates) and 7 (3 isolates). Every capsulated isolate was typeable and no palatine tonsillar sample yielded more than one serotype. Most of isolates were susceptible to low concentrations (MIC90) of amoxicillin (2 microg/mL), ceftiofur (1 microg/mL), and penicillin (1 microg/mL). No correlation was found between antimicrobial susceptibility and capsular serotype.