Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Youngjoo Sohn is active.

Publication


Featured researches published by Youngjoo Sohn.


Journal of Ethnopharmacology | 2012

Antiallergic effects of Scutellaria baicalensis on inflammation in vivo and in vitro.

Hyuk-Sang Jung; Mi Hye Kim; Nam-Gil Gwak; Yong-Seok Im; Ka-Yeon Lee; Youngjoo Sohn; Hyeon Choi; Woong Mo Yang

ETHNOPHARMACOLOGICAL RELEVANCE Scutellaria baicalensis (SB) is one of the most widely used medicinal herbs for the treatment of inflammation. In this study, we investigated the antiallergic effect of SB in vivo and in vitro. MATERIALS AND METHODS Sprague-Dawley (SD) rats received intradermal injections of anti-DNP IgE at each of three dorsal skin sites. Forty-eight hours later, each rat received an injection of DNP-HSA in saline containing 4% Evans blue through the dorsal vein of the penis. One hour before injection, SB extract was administered orally. The dorsal skin of the rats was removed and the pigment area measured. In addition, rat peritoneal mast cells (RPMCs) were cultured and purified to investigate histamine release. In vitro, human mast cells (HMC-1) were pretreated with SB extract for 30min before stimulation with phorbol 12-myristate 13-acetate (PMA) plus A23187. The effects on pro-inflammatory cytokine expression and mitogen activated protein (MAP) kinase expression were investigated using TNF-α and IL-8 assays, and Western blotting analysis of HMC-1 cells. RESULTS AND CONCLUSIONS SB treatment inhibited the passive cutaneous anaphylaxis reaction compared to the control group, and histamine release decreased significantly following treatment of RPMCs with SB. In HMC-1 cells, SB restored IL-8 and TNF-α expression and inhibited MAP kinase expression in compound 48/80-induced HMC-1 cells. These data suggest that SB may prove to be a useful anti-inflammatory agent through its downregulation of the expression of various inflammatory mediators.


Acupuncture in Medicine | 2014

The safety of acupuncture during pregnancy: a systematic review

Jimin Park; Youngjoo Sohn; Adrian White; Hyangsook Lee

Objective Although there is a growing interest in the use of acupuncture during pregnancy, the safety of acupuncture is yet to be rigorously investigated. The objective of this review is to identify adverse events (AEs) associated with acupuncture treatment during pregnancy. Methods We searched Medline, Embase, Cochrane Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Allied and Complementary Medicine Database (AMED) and five Korean databases up to February 2013. Reference lists of relevant articles were screened for additional reports. Studies were included regardless of their design if they reported original data and involved acupuncture needling and/or moxibustion treatment for any conditions in pregnant women. Studies of acupuncture for delivery, abortion, assisted reproduction or postpartum conditions were excluded. AE data were extracted and assessed in terms of severity and causality, and incidence was determined. Results Of 105 included studies, detailed AEs were reported only in 25 studies represented by 27 articles (25.7%). AEs evaluated as certain, probable or possible in the causality assessment were all mild/moderate in severity, with needling pain being the most frequent. Severe AEs or deaths were few and all considered unlikely to have been caused by acupuncture. Total AE incidence was 1.9%, and the incidence of AEs evaluated as certainly, probably or possibly causally related to acupuncture was 1.3%. Conclusions Acupuncture during pregnancy appears to be associated with few AEs when correctly applied.


Bioscience, Biotechnology, and Biochemistry | 2007

Lithospermi radix Extract Inhibits Histamine Release and Production of Inflammatory Cytokine in Mast Cells

Eun-Kyoung Kim; Eun-Young Kim; Phil-Dong Moon; Jae-Young Um; Hyung-Min Kim; Hyun-Sam Lee; Youngjoo Sohn; Seong Kyu Park; Hyuk-Sang Jung; Nak-Won Sohn

Lithospermi radix (LR, Borraginaceae, the root of Lithospermum erythrorhizon Siebold. et Zuccarinii) is used in herbal medicine to treat such conditions as eczema, skin burns and frostbite. This study investigates the effects of LR on the anti-allergy mechanism. LR inhibited the release of histamine from rat peritoneal mast cells by compound 48/80 in a dose-dependent manner. LR orally administered at 6.59 mg/100 g also inhibited the anti-DNP IgE-induced passive cutaneous anaphylaxis reaction. LR inhibited the PMA plus A23187-induced increase in IL-6, IL-8, and TNF-α expression in HMC-1 cells. In addition, LR also inhibited nuclear factor-kappa B (NF-κB) activation and IκB-α degradation. These results show that LR had an inhibitory effect on the atopic allergic reaction. Furthermore, the in vivo and in vitro anti-allergic effect of LR suggests possible therapeutic applications of this agent for inflammatory allergic diseases.


Journal of Ethnopharmacology | 2015

Xanthii fructus inhibits inflammatory responses in LPS-stimulated RAW 264.7 macrophages through suppressing NF-κB and JNK/p38 MAPK

Mijung Yeom; Jae-Hyun Kim; Ju-Hee Min; Man Ki Hwang; Hyuk-Sang Jung; Youngjoo Sohn

ETHNOPHARMACOLOGICAL RELEVANCE Xanthii fructus (XF) has long been used to treat a variety of inflammatory conditions in Korean traditional medicine, but the underlying mechanisms that could explain the anti-inflammatory actions of XF remain largely unknown. AIM OF THE STUDY This study aimed to elucidate the anti-inflammatory effects of X. fructus (XF) and to examine its underlying molecular mechanisms in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. MATERIALS AND METHODS The effect of XF on LPS-induced mRNA and protein expressions of inflammatory mediators and cytokines were determined. Moreover, the activation of the nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways and the expression of heme oxygenase-1 (HO-1) were explored to elucidate the anti-inflammatory mechanisms. RESULTS XF significantly inhibited LPS-induced production of inflammatory mediators, interleukin-6 (IL-6), nitric oxide (NO), and prostaglandin E2 (PGE2), without any cytotoxicity. However, it did not affect tissue necrosis factor (TNF)-α or IL-1β production in LPS-stimulated RAW 264.7 cells. Expression levels of inducible nitric oxide synthase (iNOS) mRNA and protein were inhibited dose-dependently by XF in LPS-stimulated RAW 264.7 cells, but there were no changes in cyclooxygenase-2 (COX-2) mRNA and protein. XF significantly attenuated LPS-induced phosphorylation and degradation of inhibitory kappa Bα (IκBα) and consequently reduced the nuclear translocation of p65 NF-κB. Pretreatment with XF also strongly inhibited the LPS-induced phosphorylation of p38 kinase and JNK, whereas the phosphorylation of ERK1/2 was not affected. In addition, XF led to an increase in HO-1 expression. CONCLUSION Taken together, our findings support that XF inhibits LPS-induced inflammatory responses by blocking NF-κB activation, inhibiting JNK/p38 MAPK phosphorylation, and enhancing HO-1 expression in macrophages, suggesting that it could be an attractive therapeutic candidate for various inflammatory diseases.


Parasites & Vectors | 2015

Current situation of scrub typhus in South Korea from 2001-2013

Hyeong-Woo Lee; Pyo Yun Cho; Sung-Ung Moon; Byoung-Kuk Na; Yoon-Joong Kang; Youngjoo Sohn; Seung-Ki Youn; Yeongseon Hong; Tong-Soo Kim

BackgroundThe bacteria Orientia tsutsugamushi is the causative agent of scrub typhus, mite-borne disease, which causes an acute febrile illness in patients. An epidemiologic study was conducted to understand the characteristics of scrub typhus in South Korea.FindingsReporting of tsutsugamushi disease is mandatory in South Korea since 1994. To investigate the prevalence of tsutsugamushi disease from 2001 to 2013, medical records from the Korea Center for Disease Control and Prevention were reviewed. In total, 70,914 cases were reported during 2001–2013. Of these, 37.16% (26,349) were male and 62.84% (44,565) were female. The highest number of cases was in the 60–69-year-old age group (19,484; 27.48%), and 72.22% (51,212) were in the 50–79-year-old age group. There were 65,100 cases (91.80%) reported during October (24,964; 35.20%) and November (40,136; 56.60%). An almost four-fold increase in the number of patients was observed in 2013 (10,485 cases) compared to 2001 (2,637 cases). The highest number of patients was reported in the Jeonbuk (9,425; 13.29%) and lowest in the Jeju (362; 0.51%).ConclusionsA rapid increase in the incidence of patients with tsutsugamushi disease was observed in most areas from 2001 to 2013, with the majority of cases reported in the western and southern coast.


Bioscience, Biotechnology, and Biochemistry | 2011

Fritillaria ussuriensis Extract Inhibits the Production of Inflammatory Cytokine and MAPKs in Mast Cells

Ik-Hyun Cho; Min Jung Lee; Jong-Hyun Kim; Na Young Han; Kyu Won Shin; Youngjoo Sohn; Hyuk-Sang Jung

Fritillaria ussuriensis (FU, derived from the bulbs of various species of the genus Fritillaria, including Fritillaria thunbergii Miq.) is used in herbal medicine to treat conditions such as eczema, skin burns, and frostbite. In this study, we investigated the mechanism of the anti-allergy effect of FU. FU extract (80 mg/kg), orally administered to Sprague-Dawley (SD) rats, significantly inhibited the passive cutaneous anaphylaxis (PCA) reaction. It inhibited the compound 48/80-induced release of histamine from rat peritoneal mast cells in a concentration-dependent manner. Significant inhibitory effects of the FU extract on IL-6, IL-8, and TNF-α (1, 10, and 100 μg/mL) were observed in HMC-1 cells. Treatment with FU attenuated PMA plus A23187-induced phosphorylation of all three MAPKs, especially at concentrations of 10 and 100 μg/mL. Further, it (80 mg/kg) led to significant inhibition of mast-cell accumulation in ear tissue at the chronic phase. These results indicate that it inhibits allergic reactions.


Malaria Journal | 2010

Prevalence of Plasmodium vivax VK210 and VK247 subtype in Myanmar.

Tong-Soo Kim; Hyung-Hwan Kim; Sun-Sim Lee; Byoung-Kuk Na; Khin Lin; Shin-Hyeong Cho; Yoon-Joong Kang; Do Kyung Kim; Youngjoo Sohn; Hyuck Kim; Hyeong-Woo Lee

BackgroundPlasmodium vivax is divided into two subtypes, a dominant form, VK210 and a variant form, VK247. This division is dependent on the amino acid composition of the circumsporozoite (CS) protein. In this study, the prevalence of the VK247 variant form of P. vivax was investigated in Myanmar.MethodsThe existence of malaria parasites in blood samples was determined by microscopic examination, polymerase chain reaction (PCR) and DNA hybridization assays. To test for antibodies against P. vivax and Plasmodium falciparum in blood samples, an indirect immunofluorescence antibody test (IFAT) was performed using asexual blood antigens. An enzyme-linked immunosorbent assay with synthetic VK210 and VK247 antigens was carried out to discriminate between the P. vivax subtypes.ResultsBy thick smear examination, 73 (n = 100) patients were single infected with P. vivax, one with P. falciparum and 13 with both species. By thin smear, 53 patients were single infected with P. vivax, eight with only P. falciparum and 16 with both. Most of the collected blood samples were shown to be P. vivax positive (n = 95) by PCR. All cases that were positive for P. falciparum by PCR (n = 43) were also positive for P. vivax. However, 52 cases were single infected with P. vivax. IFAT showed antibody titres from 1:32 to 1:4,096. Additionally, using specific antibodies for VK210 and VK247, ELISA showed that 12 patients had antibodies for only the VK210 subtype, 4 patients had only VK247 subtype antibodies and 21 patients had antibodies for both subtypes. Using a DNA hybridization test, 47 patients were infected with the VK210 type, one patient was infected with VK247 and 23 patients were infected with both subtypes.ConclusionsThe proportion of the VK247 subtype in Myanmar was 43.1% (n = 25) among 58 positive cases by serodiagnosis and 25.6% (n = 24) among 94 positive cases by genetic diagnosis. In both diagnostic methods, the infection status of malaria patients is highly diverse with respect to malaria species, and multiple clonal infections are prevalent in Myanmar. Therefore, the complexity of the infection should be considered carefully when diagnosing malaria in Myanmar.


Malaria Journal | 2013

Decreasing incidence of Plasmodium vivax in the Republic of Korea during 2010–2012

Tong-Soo Kim; Jin Su Kim; Byoung-Kuk Na; Won-Ja Lee; Heung-Chul Kim; Seung-Ki Youn; Jin Gwack; Hee Sung Kim; Pyo-Yun Cho; Seong Kyu Ahn; Seok Ho Cha; Y.W. Park; Sung-Keun Lee; Yoon-Joong Kang; Youngjoo Sohn; Yeongseon Hong; Hyeong-Woo Lee

BackgroundAfter the re-emergence of Plasmodium vivax in 1993, a total of 31,254 cases of vivax malaria were reported between 1993–2012 in the Republic of Korea (ROK). The purpose of this study was to review Korea Centers for Disease Control and Prevention records to investigate the transmission of malaria from 2010–2012.MethodsReporting of microscopy-diagnosed cases of malaria is mandatory in the ROK. In this study, all available records of malaria cases and malaria vectors collected from 2010 – 2012 in Cheorwon County, Gangwon Province and Ganghwa County, Incheon Metropolitan City, were reviewed.ResultsAlthough the number of cases of malaria peaked a third time in 2010 (1,772 cases) since the re-emergence of P. vivax, the incidence decreased two-fold to 838 in 2011 and three-fold to 555 in 2012. The number of cases decreased 52.7% in 2011 compared with that in 2010 and 33.8% in 2012 compared with that in 2011. However, the number of cases increased in Incheon Metropolitan City (15.3%) and Gyeongnam Province (23.1%) in 2012 compared with 2011. Of the 3,165 cases of vivax malaria in 2010–2012, 798 (25.2%) were in ROK military personnel, 519 (16.4%) in veterans, and 1,848 (58.4%) in civilians. In total, there were 2,666 male patients and 499 female patients, and the ratio of female to male patients increased from 1:7.9 in 2011 to 1:4.1 in 2012.ConclusionsA rapid decrease in the incidence of malaria was observed in most areas from 2010 to 2012, but the incidence increased again in the western part of the demilitarized zone. Therefore, more intensive surveillance is needed throughout high risk areas to identify factors responsible for increase/decrease in the incidence of malaria in the ROK.


Malaria Journal | 2011

Murine immune responses to a Plasmodium vivax-derived chimeric recombinant protein expressed in Brassica napus

Choonghee Lee; Hyung-Hwan Kim; Kyung Mi Choi; Kyung Won Chung; Yien Kyoung Choi; Mi Jung Jang; Tong-Soo Kim; Nam-Jun Chung; Ho-Gun Rhie; Ho-Sa Lee; Youngjoo Sohn; Hyuck Kim; Sung-Jae Lee; Hyeong-Woo Lee

BackgroundTo develop a plant-based vaccine against Plasmodium vivax, two P. vivax candidate proteins were chosen. First, the merozoite surface protein-1 (MSP-1), a major asexual blood stage antigen that is currently considered a strong vaccine candidate. Second, the circumsporozoite protein (CSP), a component of sporozoites that contains a B-cell epitope.MethodsA synthetic chimeric recombinant 516 bp gene encoding containing PvMSP-1, a Pro-Gly linker motif, and PvCSP was synthesized; the gene, named MLC, encoded a total of 172 amino acids. The recombinant gene was modified with regard to codon usage to optimize gene expression in Brassica napus. The Ti plasmid inducible gene transfer system was used for MLC chimeric recombinant gene expression in B. napus. Gene expression was confirmed by polymerase chain reaction (PCR), beta-glucuronidase reporter gene (GUS) assay, and Western blot.ResultsThe MLC chimeric recombinant protein expressed in B. napus had a molecular weight of approximately 25 kDa. It exhibited a clinical sensitivity of 84.21% (n = 38) and a clinical specificity of 100% (n = 24) as assessed by enzyme-linked immunosorbent assay (ELISA). Oral immunization of BALB/c mice with MLC chimeric recombinant protein successfully induced antigen-specific IgG1 production. Additionally, the Th1-related cytokines IL-12 (p40), TNF, and IFN-γ were significantly increased in the spleens of the BALB/c mice.ConclusionsThe chimeric MLC recombinant protein produced in B. napus has potential as both as an antigen for diagnosis and as a valuable vaccine candidate for oral immunization against vivax malaria.


Bioscience, Biotechnology, and Biochemistry | 2010

Protective Effects of Cinnamomum cassia Blume in the Fibrogenesis of Activated HSC-T6 Cells and Dimethylnitrosamine-Induced Acute Liver Injury in SD Rats

Chang-Shin Lim; Eun-Young Kim; Hyun-Sam Lee; Yunjo Soh; Youngjoo Sohn; Sun Yeou Kim; Nak-Won Sohn; Hyuk-Sang Jung; Yoon-Bum Kim

Cinnamomum cassia Blume (CC) is one of the world’s oldest natural spices, and is commonly used in traditional oriental medicine. We investigated the protective effect of ethanol extract from Cinnamomum cassia Blume (CCE) on the activation of hepatic stellate cells (HSCs). In addition, we examined the effects of CC powder in Sprague-Dawley rats with acute liver injury induced by dimethylnitrosamine (DMN). In vitro, HSC-T6 cells exhibit an activated phenotype, as reflected in their fibroblast-like morphology. CCE significantly reduced the expression of alpha-smooth muscle actin (α-SMA), connective tissue growth factor (CTGF), transforming growth factor beta (TGF-β1), and tissue inhibitor of metalloproteinase-1 (TIMP-1). In vivo, the results were significantly protected by CC powder in the serum total protein, albumin, total-bilirubin, direct-bilirubin, glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), and alkaline phosphatase (ALP). We suggest that CC inhibits fibrogenesis, followed by HSC-T6 cell activation and increased restoration of liver function, ultimately resulting in acute liver injury.

Collaboration


Dive into the Youngjoo Sohn's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Tong-Soo Kim

National Institutes of Health

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Yoon-Joong Kang

Centers for Disease Control and Prevention

View shared research outputs
Top Co-Authors

Avatar

Byoung-Kuk Na

Gyeongsang National University

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Hyung-Hwan Kim

Brigham and Women's Hospital

View shared research outputs
Top Co-Authors

Avatar

Won-Ja Lee

Centers for Disease Control and Prevention

View shared research outputs
Researchain Logo
Decentralizing Knowledge