Seobo Sim

Prevalence of pediculosis capitis among Korean children

Pediculus humanus capitis is an ectoparasite, which causes scalp pruritus particularly among children. A total of 15,373 children including 8,018 boys and 7,355 girls from 26 primary schools and 15 kindergartens attached to the primary schools and a total of 33 children from an orphanage were examined for head lice infestation (HLI). The overall prevalence of HLI in this study was 4.1% including 3.7% of the urban areas and 4.7% of the rural areas. Head lice were found more frequently in girls than in boys with prevalence of 6.5% and 1.9%, respectively. The infestation rate by school grade was 3.2%, 4.7%, 4.2%, 5.0%, 4.9%, 3.8%, and 2.1% for kindergarten, first, second, third, fourth, fifth, and sixth grades, respectively. The infestation rate of the children in an orphanage was 66.7%. The prevalence of HLI has decreased especially in the rural areas. However, HLI is a still health problem of kindergarteners and primary schoolchildren in Korea.

Protein tyrosine phosphatase SHP-2 is positively involved in platelet-derived growth factor-signaling in vascular neointima formation via the reactive oxygen species-related pathway.

The roles of Src homology domain 2-containing protein tyrosine phosphatase 2 (SHP-2) and its signaling in atherosclerosis have not been explored. Therefore, we investigated the roles of SHP-2 in the movement of rat aortic smooth muscle cells (RASMCs) and in the neointima formation of the carotid artery. Platelet-derived growth factor (PDGF)-BB (1 - 20 ng/ml) increased the activity and phosphorylation of SHP-2 and migration in RASMCs and these were suppressed by SHP-2 inhibitor NSC-87877 (30 μM) and small interfering RNA of SHP-2. PDGF-BB increased the phosphorylations of spleen tyrosine kinase (Syk) and p38 mitogen-activated protein kinase (MAPK), which were recovered by inhibition of SHP-2. Moreover, PDGF-BB increased the levels of reactive oxygen species (ROS) and ROS inhibitors decreased PDGF-BB-increased migration. Treatment of RASMCs with H2O2 (100 μM) increased cell migration and SHP-2 phosphorylation and also enhanced the phosphorylation levels of Syk and p38 MAPK. Oral administration of NSC-87877 (10 mg/kg) significantly suppressed neointima formation in a rat model of carotid artery injury. These results suggest that the activity of SHP-2 is controlled by ROS and is positively involved in the regulation of PDGF-BB-induced RASMC migration and neointima formation.

Detection of Cryptosporidium parvum in Environmental Soil and Vegetables

Cryptosporidium parvum is a zoonotic protozoan parasite that causes cryptosporidial enteritis. Numerous outbreaks of cryptosporidiosis have been reported worldwide. Cryptosporidium is transmitted to hosts via consumption of contaminated water and food but also by direct contact with contaminated soil or infected hosts. The present study investigated farm soil collected from 34 locations along the western Korean peninsula and 24 vegetables purchased from local grocery markets in Seoul. The soil and vegetable samples were examined by real-time polymerase chain reaction (qPCR) to estimate the risk of infection. Eleven of 34 locations (32.4%) and 3 of 24 vegetable samples (12.5%) were contaminated with Cryptosporidium parvum, as confirmed by TaqI enzyme digestion of qPCR products and DNA sequencing. It is suggested that Cryptosporidium infection can be mediated via farm soil and vegetables. Therefore, it is necessary to reduce contamination of this organism in view of public health. Graphical Abstract

Risk Factors Associated with Head Louse Infestation in Korea

Head louse infestation (HLI) is one of the most frequently occurring parasitic diseases in children. This study was conducted to investigate the socioeconomic and personal factors influencing HLI in the Republic of Korea. A total of 2,210 questionnaires about various factors related to HLI were obtained from children in 17 primary schools throughout the country. The rate of HLI was significantly lower in children who lived together with mother or in a family where both parents worked. In addition, HLI was lower in children whose fathers or mothers were public officers or teachers. However, HLI was higher in children who had small families and washed their hair less often. Education levels of parents and the number of children in family were not significant. Improvement of socioeconomic factors and personal hygiene will be helpful for reducing HLI.

Monthly Occurrence of Vectors and Reservoir Rodents of Scrub Typhus in an Endemic Area of Jeollanam-do, Korea

Monthly surveys were conducted to investigate the occurrence of chigger mites and seroprevalence of scrub typhus among small mammals in Jeollanam-do, the southwestern part of Korea, from November 2006 through October 2007. Fifty-eight small mammals, including 57 Apodemus agrarius (98.3%) and 1 Crocidura lasiura (1.7%), were captured, and a total of 4,675 chigger mites representing 4 genera and 8 species were collected from them. The chigger infestation rate among small mammals was 69.0%. The most predominant species in A. agrarius was Leptotrombidium scutellare (54.0%), followed by Leptotrombidium pallidum (39.4%), Leptotrombidium orientale (4.4%), Leptotrombidium palpale (1.1%), Neotrombicula tamiyai (0.6%), Eushoengastia koreaensis (0.3%), Neotrombicula gardellai (0.3%), and Cheladonta ikaoensis (<0.1%). The chigger index of A. agrarius was the highest in October (740.0), followed by November (242.0), September (134.6), March (98.3), February (38.2), January (35.3), December (34.5), April (30.8), and May (1.7). The average antibody positive rate of scrub typhus in wild rodents was 50.0%. The seropositive rates were high in October (100.0%) and November (83.3%), whereas those in other months were relatively low (28.6-57.1%). The chigger index of L. scutellare rapidly increased in September to form an acuminate peak in October, followed by a gradual decline. These results suggest that the outbreak of scrub typhus in the southwestern part of Korean peninsula is mostly due to L. scutellare.

Interaction of BOP1, a protein for ribosome biogenesis, with EB1 in Giardia lamblia

A search for a protein(s) interacting with the block of proliferation 1 (Bop1) protein of Giardia lamblia led to the isolation of end binding (EB1) protein 1, a protein that is known to function as a microtubule (MT) plus-end-tracking protein in other organisms. Interaction between Bop1 and EB1 of G. lamblia was confirmed by co-immunoprecipitation of in vitro-synthesized Bop1 and EB1 proteins. This result suggests coordination between ribosome biogenesis and cell cycle-related processes such as mitosis.

Giardia lamblia EB1 is a functional homolog of yeast Bim1p that binds to microtubules

Giardia lamblia, with two nuclei and a distinct polarized morphology, is an interesting organism for investigating how distribution of its microtubule (MT) is controlled during its cell cycle. In this study, we identified the end-binding protein 1 (EB1) of G. lamblia, a well-known microtubule-associated protein that organizes MTs in eukaryotes. Immunofluorescence assays using recombinant EB1 (rEB1)-specific antibodies demonstrated EB1 localization in nuclear membrane as well as in some cytoskeletal structures such as axomenes and median bodies of trophozoites of G. lamblia. Complementation experiments using the BIM1 knock-out mutant of yeast, the yeast homolog of mammalian EB1, showed that giardial EB1 was able to carry out a homologous function in controlling MT dynamics. In addition, rEB1 of G. lamblia co-precipitated with MTs by an in vitro binding assay, thereby demonstrating that G. lamblia EB1 is a MT-associated protein. These results, taken together, suggest that G. lamblia EB1 is a functional homolog of eukaryotic EB1 and is likely to be a determinant for MT distribution.

Proliferation of prostate stromal cell induced by benign prostatic hyperplasia epithelial cell stimulated with Trichomonas vaginalis via crosstalk with mast cell.

Chronic inflammation has a role in the pathogenesis of benign prostatic hyperplasia (BPH) and prostate cancer. Mast cells have been detected in chronic inflammatory infiltrate of the prostate, and it is possible that the interaction between prostate epithelial cells and Trichomonas vaginalis influences the activity of mast cells in the prostate stroma. Activated mast cells might influence the biological functions of nearby tissues and cells. In this study, we investigated whether mast cells reacted with the culture supernatant of BPH epithelial cells infected with T. vaginalis may induce the proliferation of prostate stromal cells.

The Epigenetic Reader BRD2 as a Specific Modulator of PAI-1 Expression in Lipopolysaccharide-Stimulated Mouse Primary Astrocytes

The post translational modification of lysine acetylation is a key mechanism that regulates chromatin structure. Epigenetic readers, such as the BET domains, are responsible for reading histone lysine acetylation which is a hallmark of open chromatin structure, further providing a scaffold that can be accessed by RNA polymerases as well as transcription factors. Recently, several reports have assessed and highlighted the roles of epigenetic readers in various cellular contexts. However, little is known about their role in the regulation of inflammatory genes, which is critical in exquisitely tuning inflammatory responses to a variety of immune stimuli. In this study, we investigated the role of epigenetic readers BRD2 and BRD4 in the lipopolysaccharide (LPS)-induced immune responses in mouse primary astrocytes. Inflammatory stimulation by LPS showed that the levels of Brd2 mRNA and protein were increased, while Brd4 mRNA levels did not change. Knocking down of Brd2 mRNA using specific small interfering RNA (siRNA) in cultured mouse primary astrocytes inhibited LPS-induced mRNA expression and secretion of plasminogen activator inhibitor-1 (PAI-1). However, no other pro-inflammatory cytokines, such as Il-6, Il-1β and Tnf-α, were affected. Indeed, treatment with bromodomain-containing protein inhibitor, JQ1, blocked Pai-1 mRNA expression through the inhibition of direct BRD2 protein-binding and active histone modification on Pai-1 promoter. Taken together, our data suggest that BRD2 is involved in the modulation of neuroinflammatory responses through PAI-1 and via the regulation of epigenetic reader BET protein, further providing a potential novel therapeutic strategy in neuroinflammatory diseases.

Human Sting of Cephalonomia gallicola (Hymenoptera: Bethylidae) in Korea

Hymenoptera stings can cause serious injury to humans. We report the clinical findings of 6 cases of Hymenoptera stings. All patients developed painful erythematous papules at the sting sites and had a past history of parasitoid wasp sting. This is the first clinical report of the parasitoid wasp, Cephalonomia gallicola, causing human stings in Korea.